Form 8-K

8-K — Altimmune, Inc.

Accession: 0001104659-26-048552

Filed: 2026-04-24

Period: 2026-04-22

CIK: 0001326190

SIC: 2834 (PHARMACEUTICAL PREPARATIONS)

Item: Entry into a Material Definitive Agreement

Item: Financial Statements and Exhibits

Documents

8-K — tm2612493d2_8k.htm (Primary)

EX-1.1 — EXHIBIT 1.1 (tm2612493d2_ex1-1.htm)

EX-4.1 — EXHIBIT 4.1 (tm2612493d2_ex4-1.htm)

EX-4.2 — EXHIBIT 4.2 (tm2612493d2_ex4-2.htm)

EX-5.1 — EXHIBIT 5.1 (tm2612493d2_ex5-1.htm)

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8-K — FORM 8-K

8-K (Primary)

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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, DC 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d)

of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported):

April 22, 2026

ALTIMMUNE, Inc.

(Exact name of registrant as specified in its

charter)

Delaware

001-32587

20-2726770

(State or other jurisdiction

of incorporation)

(Commission

File Number)

(IRS Employer

Identification No.)

910 Clopper Road, Suite 201S

Gaithersburg, Maryland

20878

(Address of principal executive offices)

(Zip Code)

Registrant’s telephone number including

area code: (240) 654-1450

(Former name or former address, if changed since

last report)

Check the appropriate box below if the Form 8-K filing is intended

to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Title of each class

Trading Symbol(s)

Name of each exchange on which registered

Common stock, par value $0.0001 per share

ALT

The NASDAQ Global Market

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405

of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company ¨

If an emerging growth company, indicate by check mark if the registrant

has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant

to Section 13(a) of the Exchange Act. ¨

Item 1.01.

Entry into a Material Definitive Agreement.

On April 22, 2026, Altimmune, Inc. (the

“Company”) entered into an underwriting agreement (the “Underwriting Agreement”) with Leerink Partners

LLC and Barclays Capital Inc., as representatives of the several underwriters named therein (the “Underwriters”) pursuant

to which the Company agreed to issue and sell (i) 64,250,000 shares of the Company’s common stock, par value $0.0001 per share

(the “Common Stock”)

and accompanying common stock warrants to purchase shares of Common Stock

(the “Common Stock Warrants”), to the Underwriters at a public offering price

of $3.00 per share and (ii) in lieu of Common Stock to certain investors that so choose, pre-funded warrants (the “Pre-Funded

Warrants” and together with the Common Stock Warrants, the “Warrants”) to purchase up to 10,750,000 shares

of Common Stock to the Underwriters at a public offering price of $2.999 per Pre-Funded Warrant (the “Offering”). Each

share of Common Stock and Pre-Funded Warrant is being offered and sold with an accompanying Common Stock Warrant to purchase shares of

Common Stock (or Pre-Funded Warrants in lieu thereof). The Offering closed on April 24, 2026.

The net proceeds to the Company from the Offering

are expected to be approximately $211.2 million after deducting the underwriting discounts and commissions and estimated offering expenses

payable by the Company. The Company intends to use the net proceeds from the Offering, together with its existing cash, cash equivalents

and marketable securities assuming the closing of the Offering, to continue to advance the clinical development of pemvidutide, including

funding and preparation for its global pivotal Phase 3 trial in metabolic dysfunction-associated steatohepatitis (“MASH”),

to initiate pre-commercial activities for its lead program, and for general corporate purposes.

Each Common Stock Warrant is exercisable for one

share of Common Stock at an exercise price of $3.00 per share. The Common Stock Warrants are exercisable at any time after their original

issuance and may be exercised until the date that is the earlier of (i) the fifth anniversary of the original issuance date and (ii) 45

days following the Company’s public announcement of a successful data readout of Phase 3 trial of pemvidutide in MASH. The “Beneficial

Ownership Limitation” shall be either 4.99% or 9.99% (at the election of the holder of the Common Stock Warrant (the “Holder”))

of the number of shares of the Common Stock outstanding immediately after giving effect to the issuance of shares of Common Stock issuable

upon exercise of the Common Stock Warrant. The Holder, upon written notice to the Company, may increase or decrease the Beneficial Ownership

Limitation provisions, provided that the Beneficial Ownership Limitation in no event exceeds 19.99% of the number of shares of the Common

Stock outstanding immediately after giving effect to the issuance of shares of Common Stock upon exercise of the Common Stock Warrant,

with additional provisions continuing to apply. Any increase in the Beneficial Ownership Limitation will not be effective until the 61st

day after such notice is delivered to the Company.

Each Pre-Funded Warrant is exercisable for one

share of common stock. The purchase price of each Pre-Funded Warrant will equal the price per share at which shares of the Company’s

common stock are being sold to the public in this offering, less the $0.001 exercise price of each Pre-Funded Warrant. The Pre-Funded

Warrants do not expire, and each Pre-Funded Warrant will be exercisable at any time after the date of issuance, subject to an ownership

limitation. The “Beneficial Ownership Limitation” shall be 9.99% of the number of shares of the Common Stock outstanding immediately

after giving effect to the issuance of shares of Common Stock issuable upon exercise of the Pre-Funded Warrant. The Holder, upon written

notice to the Company, may increase or decrease the Beneficial Ownership Limitation provisions, provided that the Beneficial Ownership

Limitation in no event exceeds 19.99% of the number of shares of the Common Stock outstanding immediately after giving effect to the issuance

of shares of Common Stock upon exercise of the Pre-Funded Warrant, with additional provisions continuing to apply. Any increase in the

Beneficial Ownership Limitation will not be effective until the 61st day after such notice is delivered to the Company.

The Company does not intend to list the Warrants

on the Nasdaq Global Market, any other national securities exchange or any other nationally recognized trading system. The foregoing summaries

of the Common Stock Warrant and of the Pre-Funded Warrant are qualified in their entirety by reference to the form of Common Stock Warrant

and the form of Pre-Funded Warrant, copies of which are attached hereto as Exhibit 4.1 and Exhibit 4.2, respectively, and incorporated

herein by reference.

The Offering was made pursuant to the Company’s

registration statements on Form S-3 (File No. 333-291329) declared effective as of December 5, 2025, a registration statement

on Form S-3 (File No. 333-285355), effective March 13, 2025 and a registration statement on Form S-3MEF (File No. 333-295254)

effective as of April 22, 2026 and filed with the Securities and Exchange Commission (the “Commission”) pursuant

to Rule 462(b) (collectively, the “Registration Statements”), each of which contains a prospectus. The preliminary

prospectus supplement and accompanying prospectus relating to and describing the terms of the Offering were filed with the Commission

on April 22, 2026 and a final prospectus was filed on April 23, 2026.

The Underwriting Agreement contains customary

representations, warranties and covenants of the Company and also provides for customary indemnification obligations of the Company and

the Underwriters, including for liabilities under the Securities Act of 1933, as amended. The representations, warranties and covenants

contained in the Underwriting Agreement were made only for purposes of such agreement and as of specific dates and were solely for the

benefit of the parties to such agreement. The foregoing summary of the Underwriting Agreement is qualified in its entirety by reference

to the Underwriting Agreement, a copy of which is attached hereto as Exhibit 1.1 and incorporated herein by reference.

Goodwin Procter LLP, counsel to the Company, delivered

an opinion as to legality of the issuance and sale of the Common Stock and the Warrants in the Offering, a copy of which is attached hereto

as Exhibit 5.1 and is incorporated herein by reference.

Cautionary Note Regarding Forward Looking Statements

This Current Report on Form 8-K and certain of the materials filed

herewith contain forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995, as amended, including,

without limitation, statements regarding the Offering and anticipated closing, and expectations regarding our cash runway, use of capital,

expenses and other future financial results. The words “may,” “might,” “will,” “could,”

“would,” “should,” “expect,” “plan,” “anticipate,” “intend,” “believe,”

“expect,” “estimate,” “seek,” “predict,” “future,” “project,”

“potential,” “continue,” “target” and similar words or expressions are intended to identify forward-looking

statements, although not all forward-looking statements contain these identifying words. Any forward-looking statements, such as those

related to the anticipated use of net proceeds from the Offering, are subject to a number of risks, uncertainties and important factors

that may cause actual events or results to differ materially from those expressed or implied by any forward-looking statements contained

in this Current Report on Form 8-K or the materials furnished or filed herewith, including, without limitation, uncertainties related

to market conditions and the completion of the Offering on the anticipated terms or at all. These and other risks and uncertainties are

described in greater detail in the section entitled “Risk Factors” in the Company’s Annual Report on Form 10-K

for the year ended December 31, 2025 and any subsequent filings with the Securities and Exchange Commission. In addition, any forward-looking

statements represent the Company’s views only as of today and should not be relied upon as representing its views as of any subsequent

date. The Company explicitly disclaims any obligation to update any forward-looking statements. No representations or warranties (expressed

or implied) are made about the accuracy of any such forward-looking statements.

Item 9.01.

Financial Statements and Exhibits.

(d) Exhibits

1.1

Underwriting

Agreement, dated as of April 22, 2026, by and between the Company, Leerink Partners LLC and Barclays Capital Inc., as representatives

of the several underwriters named therein

4.1

Form of

Common Stock Warrant.

4.2

Form of

Pre-Funded Warrant.

5.1

Opinion

of Goodwin Procter LLP

23.1

Consent

of Goodwin Procter LLP (included in Exhibit 5.1)

104

Cover

Page Interactive Data File (embedded with Inline XBRL document)

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934,

the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

ALTIMMUNE, INC.

By:

/s/ Gregory Weaver

Name: Gregory Weaver

Title: Chief Financial Officer

Dated: April 24, 2026

EX-1.1 — EXHIBIT 1.1

EX-1.1

Filename: tm2612493d2_ex1-1.htm · Sequence: 2

Exhibit 1.1

Execution Version

64,250,000 SHARES OF COMMON STOCK (PAR VALUE

$0.0001 PER SHARE)

PRE-FUNDED WARRANTS TO PURCHASE 10,750,000 SHARES OF COMMON

STOCK

WARRANTS TO PURCHASE 75,000,000 SHARES OF COMMON STOCK (OR PRE-

FUNDED WARRANTS IN LIEU THEREOF)

ALTIMMUNE, INC.

UNDERWRITING AGREEMENT

April 22, 2026

Leerink Partners LLC

Barclays Capital Inc.

As Representatives of the several Underwriters

c/o Leerink Partners LLC

53 State Street, 40th Floor

Boston, Massachusetts 02109

c/o Barclays Capital Inc.

745 Seventh Avenue

New York, New York 10019

Ladies and Gentlemen:

Introductory. Altimmune, Inc., a Delaware

corporation (the “Company”), proposes to issue and sell to the several underwriters named in Schedule A (the

“Underwriters”) (i) an aggregate of 64,250,000 shares (the “Shares”) of its common stock,

par value $0.0001 per share (the “Common Stock”); (ii) pre-funded warrants of the Company to purchase an aggregate

of 10,750,000 shares of its Common Stock (the “Pre-Funded Warrants”) in a form to be mutually agreed upon by the Company

and the Representatives; and (iii) accompanying Common Stock warrants to purchase up to an aggregate of 75,000,000 shares of Common

Stock (or Pre-Funded Warrants in lieu thereof) at an exercise price of $3.00 per share in a form to be mutually agreed upon by the Company

and the Representatives (the “Common Warrants” and together with the Pre-Funded Warrants, the “Warrants”).

The Shares and the Warrants are collectively referred to as the “Offered Securities.” Leerink Partners LLC (“Leerink

Partners”) and Barclays Capital Inc. (“Barclays”) have agreed to act as representatives of the several Underwriters

(in such capacity, the “Representatives”) in connection with the offering and sale of the Offered Securities. To the

extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall

mean you, as Underwriter, and the term “Underwriters” shall mean either the singular or the plural, as the context requires.

As used herein, “Warrant Shares” means the shares of Common Stock issuable upon exercise of the Warrants.

The Company has prepared and filed with the Securities

and Exchange Commission (the “Commission”) registration statements on Form S-3, (File Nos. 333-291329 and

333-285355), each including a base prospectus (together, the “Base Prospectuses”) to be used in connection with the

offering and sale of the Offered Securities. Such registration statements, as amended, including the financial statements, exhibits and

schedules thereto, in the form in which they became effective under the Securities Act of 1933, as amended, and the rules and regulations

promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be

incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430B

under the Securities Act, are called, collectively, the “Registration Statements.” Any registration statement filed

by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Securities

is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any

such Rule 462(b) Registration Statement the term “Registration Statements” shall include the Rule 462(b) Registration

Statement. The preliminary prospectus supplement dated April 22, 2026, if any, describing the Offered Securities and the offering

thereof (the “Preliminary Prospectus Supplement”), together with the Base Prospectuses, is called the “Preliminary

Prospectus,” and the Preliminary Prospectus and any other prospectus supplement to the Base Prospectuses in preliminary form

that describes the Offered Securities and the offering thereof and is used prior to the filing of the Prospectus (as defined below),

together with the Base Prospectuses, is called a “preliminary prospectus.” As used herein, the term “Prospectus”

shall mean the final prospectus supplement to the Base Prospectuses that describes the Offered Securities and the offering thereof (the

“Final Prospectus Supplement”), together with the Base Prospectuses in the form first used by the Underwriters to

confirm sales of the Offered Securities or in the form first made available to the Underwriters by the Company to meet requests of purchasers

pursuant to Rule 173 under the Securities Act. References herein to the Preliminary Prospectus, any preliminary prospectus and the

Prospectus shall refer to both the prospectus supplement and the Base Prospectuses of such prospectus. As used herein, the “Applicable

Time” is [9:30] p.m. (New York City time) on April 22, 2026. As used herein, “free writing prospectus”

has the meaning set forth in Rule 405 under the Securities Act, and “Time of Sale Prospectus” means the Preliminary

Prospectus, as amended or supplemented immediately prior to the Applicable Time, together with the free writing prospectus identified

in Schedule B hereto, if any, and the pricing information identified in Schedule C hereto. As used herein, “Road

Show” means a “road show” (as defined in Rule 433 under the Securities Act) relating to the offering of the

Offered Securities contemplated hereby that is a “written communication” (as defined in Rule 405 under the Securities

Act). As used herein, “Marketing Materials” means any materials or information provided to investors by, or with the

approval of, the Company in connection with the marketing of the offering of the Offered Securities, including any roadshow or investor

presentations made to investors by the Company (whether in person or electronically).

All references in this Agreement to the Registration

Statements, the Preliminary Prospectus, any preliminary prospectus, the Base Prospectuses and the Prospectus shall include the documents

incorporated or deemed to be incorporated by reference therein. All references in this Agreement to financial statements and schedules

and other information which are “contained,” “included” or “stated” in, or “part of”

the Registration Statements, the Rule 462(b) Registration Statement, the Preliminary Prospectus, any preliminary prospectus,

the Base Prospectuses, the Time of Sale Prospectus or the Prospectus, and all other references of like import, shall be deemed to mean

and include all such financial statements and schedules and other information which is or is deemed to be incorporated by reference in

the Registration Statements, the Rule 462(b) Registration Statement, the Preliminary Prospectus, any preliminary prospectus,

the Base Prospectuses, the Time of Sale Prospectus or the Prospectus, as the case may be. All references in this Agreement to amendments

or supplements to the Registration Statements, the Preliminary Prospectus, any preliminary prospectus, the Base Prospectuses, the Time

of Sale Prospectus or the Prospectus shall be deemed to mean and include the filing of any document under the Securities Exchange Act

of 1934, as amended, and the rules and regulations promulgated thereunder (collectively, the “Exchange Act”)

that is or is deemed to be incorporated by reference in the Registration Statements, the Preliminary Prospectus, any preliminary prospectus,

the Base Prospectuses, or the Prospectus, as the case may be. All references in this Agreement to (i) the Registration Statements,

the Preliminary Prospectus, any preliminary prospectus, the Base Prospectuses or the Prospectus, any amendments or supplements to any

of the foregoing, or any free writing prospectus, shall include any copy thereof filed with the Commission pursuant to its Electronic

Data Gathering, Analysis and Retrieval System (“EDGAR”) and (ii) the Prospectus shall be deemed to include any

“electronic Prospectus” provided for use in connection with the offering of the Offered Securities as contemplated by Section 3(n) of

this Agreement.

In the event that the Company has only one subsidiary,

then all references herein to “subsidiaries” of the Company shall be deemed to refer to such single subsidiary, mutatis mutandis.

The Company hereby confirms its agreements with

the Underwriters as follows:

Section 1.               Representations

and Warranties.

The Company hereby represents, warrants and covenants

to each Underwriter, as of the date of this Agreement, as of the Closing Date (as hereinafter defined), as follows:

(a)            Compliance

with Registration Requirements. The Registration Statements have become effective under the Securities Act. The Company has complied,

to the Commission’s satisfaction, with all requests of the Commission for additional or supplemental information, if any. No stop

orders suspending the effectiveness of either registration statement comprising the Registration Statements is in effect and no proceedings

for such purpose have been instituted or are pending or, to the knowledge of the Company, are contemplated or threatened by the Commission.

At the time the Company’s Annual Report on Form 10-K for the year ended December 31, 2025 (the “Annual Report”)

was filed with the Commission, or, if later, at the time each registration statement comprising the Registration Statements was originally

filed with the Commission, the Company met the then applicable requirements for use of Form S-3 under the Securities Act. As of

the date of this Agreement, the Company meets the requirements for use of Form S-3 under the Securities Act specified in FINRA Conduct

Rule 5110(h)(1)(C). The Commission has not notified the Company of any objection to the use of the form of either registration statement

comprising the Registration Statements or any post-effective amendment thereto. The documents incorporated or deemed to be incorporated

by reference in the Registration Statements, the Time of Sale Prospectus and the Prospectus, at the time they were or hereafter are filed

with the Commission, or became effective under the Exchange Act, as the case may be, complied and will comply in all material respects

with the requirements of the Exchange Act.

(b)            Disclosure.

Each preliminary prospectus and the Prospectus when filed complied in all material respects with the Securities Act and, if filed by

electronic transmission pursuant to EDGAR, was identical (except as may be permitted by Regulation S-T under the Securities Act)

to the copy thereof delivered to the Underwriters for use in connection with the offer and sale of the Offered Securities. Each of the

registration statements comprising the Registration Statements and any post-effective amendment thereto, at the time it became or becomes

effective, complied and will comply in all material respects with the Securities Act and did not and will not contain any untrue statement

of a material fact or omit to state a material fact required to be stated therein or necessary to make the statements therein not misleading.

As of the Applicable Time, the Time of Sale Prospectus did not, and at the Closing Date, will not, contain any untrue statement of a

material fact or omit to state a material fact necessary to make the statements therein, in light of the circumstances under which they

were made, not misleading. The Prospectus, as of its date, did not, and at the Closing Date, will not, contain any untrue statement of

a material fact or omit to state a material fact necessary in order to make the statements therein, in light of the circumstances under

which they were made, not misleading. The representations and warranties set forth in the three immediately preceding sentences do not

apply to statements in or omissions from the Registration Statements or any post-effective amendment thereto, or the Prospectus or the

Time of Sale Prospectus, or any amendments or supplements thereto, made in reliance upon and in conformity with written information relating

to any Underwriter furnished to the Company in writing by the Representatives expressly for use therein, it being understood and agreed

that the only such information consists of the information described in Section 9(b) below. The documents incorporated by reference

in the Time of Sale Prospectus or the Prospectus did not, and any further documents filed and incorporated by reference therein will

not, when filed with the Commission, contain an untrue statement of a material fact or omit to state a material fact necessary to make

the statements therein, in the light of the circumstances under which they were made, not misleading. There are no contracts or other

documents required to be described in the Time of Sale Prospectus or the Prospectus or to be filed as an exhibit to either of registration

statement comprising the Registration Statements which have not been described or filed as required.

Writing Prospectuses; Road Show. As of the determination date referenced in Rule 164(h) under the Securities

Act, the Company was not, is not or will not be (as applicable) an “ineligible issuer”

in connection with the offering of the Offered Securities pursuant to Rules 164, 405

and 433 under the Securities Act. Each free writing prospectus that the Company is required to file pursuant to Rule 433(d) under

the Securities Act has been, or will be, filed with the Commission in accordance with the requirements of the Securities Act and the

applicable rules and regulations of the Commission thereunder. Each free writing prospectus that the Company has filed, or is required

to file, pursuant to Rule 433(d) under the Securities Act or that was prepared by or on behalf of or used or referred to by

the Company complies or will comply in all material respects with the requirements of Rule 433 under the Securities Act, including

timely filing with the Commission, retention and legending, as applicable, and each such free writing prospectus, as of its issue date

and at all subsequent times through the completion of the offer and sale of the Offered Securities did not, does not and will not include

any information that conflicted, conflicts or will conflict with the information contained in the Registration Statements, the Prospectus

or any preliminary prospectus unless such information has been superseded or modified as of such time. Except for the free writing prospectuses,

if any, identified in Schedule B, and electronic road shows, if any, each furnished to the Representatives before first use, the

Company has not prepared, used or referred to, and will not, without the Representatives’ prior written consent, prepare, use or

refer to, any free writing prospectus. Each Road Show, when considered together with the Time of Sale Prospectus, did not, as

of the Applicable Time, contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements

therein, in light of the circumstances under which they were made, not misleading.

(d)            Distribution

of Offering Material By the Company. Prior to the later of (i) the completion of the Underwriters’ distribution of

the Offered Securities and (ii) the expiration of 30 days after the date of the Prospectus, the Company has not distributed and

will not distribute any offering material in connection with the offering and sale of the Offered Securities other than the Registration

Statements, the Time of Sale Prospectus, the Prospectus or any free writing prospectus reviewed and consented to by the Representatives,

and free writing prospectuses, if any, identified on Schedule B hereto.

(e)            The

Underwriting Agreement. This Agreement has been duly authorized, executed and delivered by the Company.

(f)            Authorization

of the Shares. The Shares have been duly authorized for issuance and sale pursuant to this Agreement and, when issued and delivered

by the Company against payment therefor pursuant to this Agreement, will be duly and validly issued, fully paid and nonassessable, free

and clear of any pledge, lien, encumbrance, security interest or other claim, including any statutory or contractual preemptive rights,

resale rights, rights of first refusal or other similar rights, and will be registered pursuant to Section 12 of the Exchange Act.

(g)            Authorization

of the Warrants. The Warrants have been duly authorized and, when executed and delivered by the Company in accordance with this

Agreement, will be valid and legally binding agreements of the Company, enforceable against the Company in accordance with their terms

except as the enforcement thereof may be limited by applicable bankruptcy, insolvency, reorganization, moratorium or other similar laws

relating to or affecting the rights and remedies of creditors or by general equitable principles. The Warrant Shares to be issued by

the Company upon exercise of the Warrants in accordance therewith have been duly authorized and reserved for issuance upon exercise of

the Warrants in a number sufficient to meet the current exercise requirements. The Warrant Shares, when issued and delivered upon exercise

of the Warrants in accordance therewith, will be validly issued, fully paid and nonassessable, free and clear of any pledge, lien, encumbrance,

security interest or other claim, including any statutory or contractual preemptive rights, resale rights, rights of first refusal or

other similar rights, and will be registered pursuant to Section 12 of the Exchange Act.

(h)            No

Applicable Registration or Other Similar Rights. There are no persons with registration or other similar rights to have any equity

or debt securities registered for sale under the Registration Statements or included in the offering contemplated by this Agreement,

except for such rights as have been duly waived.

(i)            No

Material Adverse Change. Except as otherwise disclosed in the Registration Statements, the Time of Sale Prospectus and the Prospectus,

subsequent to the respective dates as of which information is given in the Registration Statements, the Time of Sale Prospectus and the

Prospectus: (i) there has been no material adverse change, or any development that could be reasonably expected to result in a material

adverse change, in (A) the condition, financial or otherwise, or in the earnings, business, properties, operations, operating results,

assets, liabilities or prospects, whether or not arising from transactions in the ordinary course of business, of the Company and its

subsidiaries, considered as one entity or (B) the ability of the Company to consummate the transactions contemplated by this Agreement

or perform its obligations hereunder (any such change being referred to herein as a “Material Adverse Change”); (ii) the

Company and its subsidiaries, considered as one entity, have not incurred any material liability or obligation, indirect, direct or contingent,

including without limitation any losses or interference with their business from fire, explosion, flood, earthquakes, accident or other

calamity, whether or not covered by insurance, or from any strike, labor dispute or court or governmental action, order or decree, that

are material, individually or in the aggregate, to the Company and its subsidiaries, considered as one entity, and have not entered into

any transactions not in the ordinary course of business; and (iii) there has not been any material decrease in the capital stock

or any material increase in any short-term or long-term indebtedness of the Company or its subsidiaries and there has been no dividend

or distribution of any kind declared, paid or made by the Company or, except for dividends paid to the Company or other subsidiaries,

by any of the Company’s subsidiaries on any class of capital stock, or any repurchase or redemption by the Company or any of its

subsidiaries of any class of capital stock.

(j)            Independent

Accountants. Ernst & Young LLP, which has expressed its opinion with respect to the financial statements (which term

as used in this Agreement includes the related notes thereto) filed with the Commission as a part of the Registration Statements, the

Time of Sale Prospectus and the Prospectus, is (i) an independent registered public accounting firm as required by the Securities

Act, the Exchange Act, and the rules of the Public Company Accounting Oversight Board (“PCAOB”), (ii) in

compliance with the applicable requirements relating to the qualification of accountants under Rule 2-01 of Regulation S-X under

the Securities Act and (iii) a registered public accounting firm as defined by the PCAOB whose registration has not been suspended

or revoked and who has not requested such registration to be withdrawn.

(k)          Financial

Statements. The financial statements filed with the Commission as a part of or incorporated by reference in the Registration

Statements, the Time of Sale Prospectus and the Prospectus present fairly, in all material respects, the consolidated financial position

of the Company and its subsidiaries as of the dates indicated and the results of their operations, changes in stockholders’ equity

and cash flows for the periods specified. Such financial statements comply as to form in all material respects with the requirements

of Regulation S-X under the Securities Act and have been prepared in conformity with generally accepted accounting principles applied

on a consistent basis throughout the periods involved, except as may be expressly stated in the related notes thereto. The interactive

data in eXtensible Business Reporting Language included or incorporated by reference in the Registration Statements fairly presents the

information called for in all material respects and has been prepared in accordance with the Commission’s rules and guidelines

applicable thereto. No other financial statements or supporting schedules are required to be included in the Registration Statements,

the Time of Sale Prospectus or the Prospectus. The financial data incorporated by reference into each of the registration statements

comprising the Registration Statements, the Time of Sale Prospectus and the Prospectus fairly presents the information set forth therein

on a basis consistent with that of the audited financial statements contained in the Registration Statements, the Time of Sale Prospectus

and the Prospectus. To the Company’s knowledge, no person who has been suspended or barred from being associated with a registered

public accounting firm, or who has failed to comply with any sanction pursuant to Rule 5300 promulgated by the PCAOB, has participated

in or otherwise aided in the preparation of, or audited, the financial statements, supporting schedules or other financial data filed

with the Commission as a part of the Registration Statements, the Time of Sale Prospectus, and the Prospectus.

(l)            Company’s

Accounting System. The Company and each of its subsidiaries make and keep accurate books and records and maintain a system of

internal accounting controls designed, and which the Company reasonably believes is sufficient, to provide reasonable assurance that:

(i) transactions are executed in accordance with management’s general or specific authorization; (ii) transactions are

recorded as necessary to permit preparation of financial statements in conformity with GAAP and to maintain accountability for assets;

(iii) access to assets is permitted only in accordance with management’s general or specific authorization; (iv) the

recorded accountability for assets is compared with existing assets at reasonable intervals and appropriate action is taken with respect

to any differences; and (v) the interactive data in eXtensible Business Reporting Language included or incorporated by reference

in the Registration Statements, the Time of Sale Prospectus and the Prospectus fairly presents the information called for in all material

respects and is prepared in accordance with the Commission's rules and guidelines applicable thereto.

(m)          Disclosure

Controls and Procedures; Deficiencies in or Changes to Internal Control Over Financial Reporting. The Company has established

and maintains disclosure controls and procedures (as defined in Rules 13a-15 and 15d-15 under the Exchange Act), which (i) are

designed to ensure that material information relating to the Company, including its consolidated subsidiaries, is made known to the Company’s

principal executive officer and its principal financial officer by others within those entities, particularly during the periods in which

the periodic reports required under the Exchange Act are being prepared; (ii) have been evaluated by management of the Company for

effectiveness as of the end of the Company’s most recent fiscal quarter; and (iii) are effective in all material respects

to perform the functions for which they were established. Since the end of the Company’s most recent audited fiscal year, there

have been no significant deficiencies or material weakness in the Company’s internal control over financial reporting (whether

or not remediated) and no change in the Company’s internal control over financial reporting that has materially affected, or is

reasonably likely to materially affect, the Company’s internal control over financial reporting. The Company is not aware of any

fraud, whether or not material, that involves management or other employees who have a significant role in the internal controls of the

Company and each of its subsidiaries or any change in its internal control over financial reporting that has occurred during its most

recent fiscal quarter that has materially affected, or is reasonably likely to materially affect, the Company’s internal control

over financial reporting.

(n)           Incorporation

and Good Standing of the Company. The Company has been duly incorporated and is validly existing as a corporation in good standing

under the laws of the jurisdiction of its incorporation and has the corporate power and authority to own, lease and operate its properties

and to conduct its business as described in the Registration Statements, the Time of Sale Prospectus and the Prospectus and to enter

into and perform its obligations under this Agreement. The Company is duly qualified as a foreign corporation to transact business and

is in good standing in the State of Delaware and each other jurisdiction in which such qualification is required, whether by reason of

the ownership or leasing of property or the conduct of business, except where the failure to be so qualified could not reasonably be

expected, individually or in the aggregate, to have a Material Adverse Change.

(o)            Subsidiaries.

Each of the Company’s “subsidiaries” (for purposes of this Agreement, as defined in Rule 405 under the Securities

Act) has been duly incorporated or organized, as the case may be, and is validly existing as a corporation, partnership or limited liability

company, as applicable, in good standing under the laws of the jurisdiction of its incorporation or organization and has the power and

authority (corporate or other) to own, lease and operate its properties and to conduct its business as described in the Registration

Statements, the Time of Sale Prospectus and the Prospectus, except where the failure to be in good standing could not reasonably be expected,

individually or in the aggregate, to have a Material Adverse Change. Each of the Company’s subsidiaries is duly qualified as a

foreign corporation, partnership or limited liability company, as applicable, to transact business and is in good standing in each jurisdiction

in which such qualification is required, whether by reason of the ownership or leasing of property or the conduct of business, except

where the failure to be so qualified could not reasonably be expected, individually or in the aggregate, to have a Material Adverse Change.

All of the issued and outstanding capital stock or other equity or ownership interests of each of the Company’s subsidiaries have

been duly authorized and validly issued, are fully paid and nonassessable and are owned by the Company, directly or through subsidiaries,

free and clear of any security interest, mortgage, pledge, lien, encumbrance or adverse claim. None

of the outstanding capital stock or equity interest in any subsidiary of the Company was issued in violation of preemptive or similar

rights of any security holder of such subsidiary. The constitutive or organizational documents of each of the Company’s subsidiaries

comply in all material respects with the requirements of applicable laws of its jurisdiction of incorporation or organization and are

in full force and effect. The Company does not own or control, directly or indirectly, any corporation, association or other entity

other than the subsidiaries listed in Exhibit 21 to the Company’s most recent Annual Report on Form 10-K.

(p)            Capitalization

and Other Capital Stock Matters. The authorized, issued and outstanding capital stock of the Company is as set forth in the Registration

Statements and the Time of Sale Prospectus (other than for subsequent issuances, if any, pursuant to employee benefit plans, or upon

the exercise of outstanding options or warrants, in each case described in the Registration Statements, the Time of Sale Prospectus and

the Prospectus). All of the issued and outstanding shares of Common Stock have been duly authorized and validly issued, are fully paid

and nonassessable and have been issued in compliance with all federal and state laws and conform to the description thereof contained

in the Time of Sale Prospectus. None of the outstanding shares of Common Stock was issued in violation of any preemptive rights, rights

of first refusal or other similar rights to subscribe for or purchase securities of the Company. There are no authorized or outstanding

options, warrants, preemptive rights, rights of first refusal or other rights to purchase, or equity or debt securities convertible into

or exchangeable or exercisable for, any capital stock of the Company or any of its subsidiaries other than those described in the Registration

Statements, the Time of Sale Prospectus and the Prospectus and, if any, they have been duly authorized and validly issued, conform to

the description thereof contained in the Registration Statements, the Time of Sale Prospectus and the Prospectus and were issued in compliance

with federal and state securities laws. The descriptions of the Company’s stock option, stock bonus and other stock plans or arrangements,

and the options or other rights granted thereunder, set forth in the Registration Statements, the Time of Sale Prospectus and the Prospectus

accurately and fairly presents, in all material respects, the information required to be shown with respect to such plans, arrangements,

options and rights. The description of the Offered Securities, including the Warrant Shares, in the Registration Statements, the Time

of Sale Prospectus and the Prospectus is complete and accurate in all material respects. Except as disclosed in or contemplated by the

Registration Statements, the Time of Sale Prospectus or Prospectus, as of the date referred to therein, the Company does not have outstanding

any options to purchase, or any rights or warrants to subscribe for, or any securities or obligations convertible into, or exchangeable

for, or any contracts or commitments to issue or sell, any shares of capital stock or other securities.

(q)            Stock

Exchange Listing. The Common Stock is registered pursuant to Section 12(b) or 12(g) of the Exchange Act and is

listed on The Nasdaq Global Market (“Nasdaq”), and the Company has taken no action designed to, or likely to have

the effect of, terminating the registration of the Common Stock under the Exchange Act or delisting the Common Stock from Nasdaq, nor

has the Company received any notification that the Commission or the Nasdaq is contemplating terminating such registration or listing.

To the Company’s knowledge, it is in compliance with all applicable listing requirements of Nasdaq.

(r)            Non-Contravention

of Existing Instruments; No Further Authorizations or Approvals Required. Neither the Company nor any of its subsidiaries is

in violation of its charter or by-laws, partnership agreement or operating agreement or similar organizational documents, as applicable,

or is in default (or, with the giving of notice or lapse of time, would be in default) (“Default”) under any indenture,

loan, credit agreement, note, lease, license agreement, contract, franchise or other instrument (including, without limitation, any pledge

agreement, security agreement, mortgage or other instrument or agreement evidencing, guaranteeing, securing or relating to indebtedness)

to which the Company or any of its subsidiaries is a party or by which it or any of them may be bound, or to which any of their respective

properties or assets are subject (each, an “Existing Instrument”), except for such Defaults as would not reasonably

be expected, individually or in the aggregate, to result in a Material Adverse Change. The Company’s execution, delivery and performance

of this Agreement and the Warrants, consummation of the transactions contemplated hereby and by the Registration Statements, the Time

of Sale Prospectus and the Prospectus and the issuance and sale of the Offered Securities (including the use of proceeds from the sale

of the Offered Securities as described in the Registration Statements, the Time of Sale Prospectus and the Prospectus under the caption

“Use of Proceeds”) and the issuance of the Warrant Shares upon exercise of the Warrants (i) have been duly authorized

by all necessary corporate action and will not result in any violation of the provisions of the charter or by-laws, partnership agreement

or operating agreement or similar organizational documents, as applicable, of the Company or any subsidiary, (ii) will not conflict

with or constitute a breach of, or Default or a Debt Repayment Triggering Event (as defined below) under, or result in the creation or

imposition of any lien, charge or encumbrance upon any property or assets of the Company or any of its subsidiaries pursuant to, or require

the consent of any other party to, any Existing Instrument, and (iii) will not result in any violation of any law, administrative

regulation or administrative or court decree applicable to the Company or any of its subsidiaries, except in the case of clauses (ii) and

(iii), as would not reasonably be expected, individually or in the aggregate, to have a Material Adverse Change. No consent, approval,

authorization or other order of, or registration or filing with, any court or other governmental or regulatory authority or agency, is

required for the Company’s execution, delivery and performance of this Agreement, the Warrants and consummation of the transactions

contemplated hereby and by the Registration Statements, the Time of Sale Prospectus and the Prospectus, except such as have been obtained

or made by the Company and are in full force and effect under the Securities Act and such as may be required under applicable state securities

or blue sky laws or the Financial Industry Regulatory Authority, Inc. (“FINRA”) or Nasdaq. As used herein, a

“Debt Repayment Triggering Event” means any event or condition which gives, or with the giving of notice or lapse

of time would give, the holder of any note, debenture or other evidence of indebtedness (or any person acting on such holder’s

behalf) the right to require the repurchase, redemption or repayment of all or a portion of such indebtedness by the Company or any of

its subsidiaries.

(s)            Compliance

with Laws. The Company and its subsidiaries have been and are in compliance with all applicable laws, rules and regulations,

except where failure to be so in compliance could not be expected, individually or in the aggregate, to have a Material Adverse Change.

(t)             No

Material Actions or Proceedings. Except as otherwise disclosed in the Registration Statements, the Time of Sale Prospectus and

the Prospectus, there is no action, suit, proceeding, inquiry or investigation brought by or before any legal or governmental entity

now pending or, to the knowledge of the Company, threatened, against or affecting the Company or any of its subsidiaries, which could

be expected, individually or in the aggregate, to have a Material Adverse Change or materially and adversely affect the consummation

of the transactions contemplated by this Agreement or the performance by the Company of its obligations hereunder; and the aggregate

of all pending legal or governmental proceedings to which the Company or any such subsidiary is a party or of which any of their respective

properties or assets is the subject, including ordinary routine litigation incidental to the business, if determined adversely to the

Company, would not reasonably be expected to have a Material Adverse Change. No material labor dispute with the employees of the Company

or any of its subsidiaries, or with the employees of any principal supplier, manufacturer, customer or contractor of the Company, exists

or, to the knowledge of the Company, is threatened or imminent.

(u)            Intellectual

Property Rights. The Company and its subsidiaries own, or have obtained valid and enforceable licenses for, the inventions, patent

applications, patents, trademarks, trade names, service names, copyrights, trade secrets and other intellectual property described in

the Registration Statements, the Time of Sale Prospectus and the Prospectus as being owned or licensed by them or which are necessary

for the conduct of their respective businesses as currently conducted or as currently proposed to be conducted (collectively, “Intellectual

Property”) except as could not reasonably be expected, individually or in the aggregate, to have a Material Adverse Change.

To the Company’s knowledge, and except for such third-party rights or infringements that could not reasonably be expected, individually

or in the aggregate, to have a Material Adverse Change, and the conduct of their respective businesses does not and will not infringe,

misappropriate or otherwise conflict in any material respect with any such rights of others. The Intellectual Property of the Company

has not been adjudged by a court of competent jurisdiction to be invalid or unenforceable, in whole or in part, and the Company is unaware

of any facts which would form a reasonable basis for any such adjudication. To the Company's knowledge: (i) there are no third parties

who have rights to any Intellectual Property, except for customary reversionary rights of third-party licensors with respect to Intellectual

Property that is disclosed in the Registration Statements, the Time of Sale Prospectus and the Prospectus as licensed to the Company

or one or more of its subsidiaries; and (ii) there is no infringement by third parties of any Intellectual Property. There is no

pending or, to the Company’s knowledge, threatened action, suit, proceeding or claim by others: (A) challenging the Company’s

rights in or to any Intellectual Property, and the Company is unaware of any facts which would form a reasonable basis for any such action,

suit, proceeding or claim; (B) challenging the validity, enforceability or scope of any Intellectual Property, and the Company is

unaware of any facts which would form a reasonable basis for any such action, suit, proceeding or claim; or (C) asserting that the

Company or any of its subsidiaries infringes or otherwise violates, or would, upon the commercialization of any product or service described

in the Registration Statements, the Time of Sale Prospectus or the Prospectus as under development, infringe or violate, any patent,

trademark, trade name, service name, copyright, trade secret or other proprietary rights of others, and the Company is unaware of any

facts which would form a reasonable basis for any such action, suit, proceeding or claim. The Company and its subsidiaries have complied

with the terms of each agreement pursuant to which Intellectual Property has been licensed to the Company or any subsidiary, and all

such agreements are in full force and effect. To the Company’s knowledge, there are no material defects in any of the patents or

patent applications included in the Intellectual Property. All employees or contractors engaged on behalf of the Company or any of its

subsidiaries in the development of Intellectual Property Rights have executed an invention assignment agreement whereby such employees

or contractors presently assign all of their right, title and interest in and to such Intellectual Property Rights to the Company or

the applicable subsidiary, and no such agreement has been breached or violated. The Company and its subsidiaries have taken all reasonable

steps to protect, maintain and safeguard their Intellectual Property, including the execution of appropriate employment contracts, patent

disclosure agreements, invention assignment agreements, invention assignments, non-competition agreements, non-solicitation agreements,

and nondisclosure agreements with their employees, and no employee of the Company is in or has been in violation of any term of any employment

contract, patent disclosure agreement, invention assignment agreement, non-competition agreement, non-solicitation agreement, nondisclosure

agreement, or any restrictive covenant to or with a former employer where the basis of such violation relates to such employee’s

employment with the Company. The duty of candor and good faith as required by the United States Patent and Trademark Office during the

prosecution of the United States patents and patent applications included in the Intellectual Property have been complied with; and in

all foreign offices having similar requirements, all such requirements have been complied with. None of the Company owned Intellectual

Property or technology (including information technology and outsourced arrangements) employed by the Company or its subsidiaries has

been obtained or is being used by the Company or its subsidiary in violation of any contractual obligation binding on the Company or

its subsidiaries or any of their respective officers, directors or employees or otherwise in violation of the rights of any persons.

The product candidates described in the Registration Statements, the Time of Sale Prospectus and the Prospectus as under development

by the Company or any subsidiary fall within the scope of the claims of one or more patents or patent applications owned by, or exclusively

licensed to, the Company or any subsidiary.

(v)             All

Necessary Permits, etc. The Company and its subsidiaries possess such valid and current certificates, authorizations or

permits required by state, federal or foreign regulatory agencies or bodies to conduct their respective businesses as currently conducted

and as described in the Registration Statements, the Time of Sale Prospectus or the Prospectus (“Permits”), except

where failure to so possess would not reasonably be expected to, individually or in the aggregate, result in a Material Adverse Change.

Neither the Company nor any of its subsidiaries is in violation of, or in default under, any of the Permits or has received any notice

of proceedings relating to the revocation or modification of, or non-compliance with, any such certificate, authorization or permit,

except as where such violation, default, revocation, modification or non-compliance could not reasonably be expected, individually or

in the aggregate, to have a Material Adverse Change.

(w)            Title

to Properties. The Company and its subsidiaries have good and marketable title to all of the real and personal property and other

assets reflected as owned in the financial statements referred to in Section 1(k) above (or elsewhere in the Registration Statements,

the Time of Sale Prospectus or the Prospectus), in each case free and clear of any security interests, mortgages, liens, encumbrances,

equities, adverse claims and other defects, except where failure to so possess would not reasonably be expected to, individually or in

the aggregate, result in a Material Adverse Change. The real property, improvements, equipment and personal property held under lease

by the Company or any of its subsidiaries are held under valid and enforceable leases, with such exceptions as are not material and do

not materially interfere with the use made or proposed to be made of such real property, improvements, equipment or personal property

by the Company or such subsidiary.

(x)            Tax

Law Compliance. The Company and its subsidiaries have filed all federal, state, local and foreign tax returns required to be

filed by the Company and its subsidiaries or have properly requested extensions thereof (and such returns were when filed complete and

correct in all material respects), and have paid all taxes required to be paid by any of them and, if due and payable, any related or

similar assessment, fine or penalty levied against any of them, except as may be being contested in good faith and by appropriate proceedings

or where the failure to file such tax returns or to pay such taxes would not, individually or in the aggregate, result in a Material

Adverse Change. The Company has made adequate charges, accruals and reserves in the applicable financial statements referred to in Section 1(k) in

respect of all taxes for all periods as to which the tax liability of the Company or any of its subsidiaries has not been finally determined.

The Company and its subsidiaries do not have any tax deficiencies or claims outstanding or assessed or, to the Company’s knowledge,

proposed against them, except as would not, individually or in the aggregate, result in a Material Adverse Change.

(y)            Insurance.

Each of the Company and its subsidiaries are insured by recognized, financially sound and reputable institutions with policies in such

amounts and with such deductibles and covering such risks as are generally deemed adequate and customary for their businesses including,

but not limited to, policies covering real and personal property owned or leased by the Company and its subsidiaries against theft, damage,

destruction, acts of vandalism and earthquakes and policies covering the Company and its subsidiaries for product liability claims and

clinical trial liability claims. The Company has no reason to believe that it or any of its subsidiaries will not be able (i) to

renew its existing insurance coverage as and when such policies expire or (ii) to obtain comparable coverage from similar institutions

as may be necessary or appropriate to conduct its business as now conducted and at a cost that could not be expected to have a Material

Adverse Change. Neither the Company nor any of its subsidiaries has been denied any insurance coverage which it has sought or for which

it has applied.

(z)            Compliance

with Environmental Laws. Except as could not be expected, individually or in the aggregate, to have a Material Adverse Change:

(i) neither the Company nor any of its subsidiaries is in violation of any federal, state, local or foreign statute, law, rule,

regulation, ordinance, code, policy or rule of common law or any judicial or administrative interpretation thereof, including any

judicial or administrative order, consent, decree or judgment, relating to pollution or protection of human health, the environment (including,

without limitation, ambient air, surface water, groundwater, land surface or subsurface strata) or wildlife, including, without limitation,

laws and regulations relating to the release or threatened release of chemicals, pollutants, contaminants, wastes, toxic substances,

hazardous substances, petroleum or petroleum products (collectively, “Hazardous Materials”) or to the manufacture,

processing, distribution, use, treatment, storage, disposal, transport or handling of Hazardous Materials (collectively, “Environmental

Laws”); (ii) the Company and its subsidiaries have all permits, authorizations and approvals required under any applicable

Environmental Laws and are each in compliance with their requirements; (iii) there are no pending or threatened administrative,

regulatory or judicial actions, suits, demands, demand letters, claims, liens, notices of non-compliance or violation, investigation

or proceedings relating to any Environmental Law against the Company or any of its subsidiaries; and (iv) to the Company’s

knowledge, there are no events or circumstances that might reasonably be expected to form the basis of an order for clean-up or remediation,

or an action, suit or proceeding by any private party or governmental body or agency, against or affecting the Company or any of its

subsidiaries relating to Hazardous Materials or any Environmental Laws.

(aa)           ERISA

Compliance. The Company and its subsidiaries and any “employee benefit plan” (as defined under the Employee Retirement

Income Security Act of 1974, as amended, and the regulations and published interpretations thereunder (collectively, “ERISA”))

established or maintained by the Company, its subsidiaries or, to the knowledge of the Company, their “ERISA Affiliates”

(as defined below) are in compliance in all material respects with ERISA. “ERISA Affiliate” means, with respect to

the Company or any of its subsidiaries, any member of any group of organizations described in Sections 414(b), (c), (m) or

(o) of the Internal Revenue Code of 1986, as amended, and the regulations and published interpretations thereunder (the “Code”)

of which the Company or such subsidiary is a member. No “reportable event” (as defined under ERISA) has occurred or is reasonably

expected to occur with respect to any “employee benefit plan” established or maintained by the Company, its subsidiaries

or any of their ERISA Affiliates. No “employee benefit plan” established or maintained by the Company, its subsidiaries or

any of their ERISA Affiliates, if such “employee benefit plan” were terminated, would have any “amount of unfunded

benefit liabilities” (as defined under ERISA). Neither the Company, its subsidiaries nor any of their ERISA Affiliates has incurred

or reasonably expects to incur any liability under (i) Title IV of ERISA with respect to termination of, or withdrawal from,

any “employee benefit plan” or (ii) Sections 412, 4971, 4975 or 4980B of the Code. Each employee benefit plan established

or maintained by the Company, its subsidiaries or any of their ERISA Affiliates that is intended to be qualified under Section 401(a) of

the Code is so qualified and, nothing has occurred, to the Company’s knowledge, whether by action or failure to act, which would

cause the loss of such qualification.

(bb)           Company

Not an “Investment Company.” The Company is not, and will not be, either after receipt of payment for the Offered

Securities or after the application of the proceeds therefrom as described under “Use of Proceeds” in the Registration Statements,

the Time of Sale Prospectus or the Prospectus, required to register as an “investment company” under the Investment Company

Act of 1940, as amended (the “Investment Company Act”).

(cc)           No

Price Stabilization or Manipulation; Compliance with Regulation M. Neither the Company nor any of its subsidiaries has taken,

directly or indirectly, any action designed to or that would reasonably be expected to cause or result in stabilization or manipulation

of the price of the Shares or of any “reference security” (as defined in Rule 100 of Regulation M under the Exchange

Act (“Regulation M”)) with respect to the Shares, whether to facilitate the sale or resale of the Offered Securities

or otherwise, and has taken no action which would directly or indirectly violate Regulation M.

(dd)           Related-Party

Transactions. There are no business relationships or related-party transactions involving the Company or any of its subsidiaries

or any other person required to be described in the Registration Statements, the Time of Sale Prospectus or the Prospectus that have

not been described as required.

(ee)           FINRA

Matters. All of the information provided to the Underwriters or to counsel for the Underwriters by the Company, its counsel,

its officers and directors and to the Company’s knowledge, the holders of any securities (debt or equity) or options to acquire

any securities of the Company in connection with the offering of the Offered Securities is true, complete, correct in all material respects

and compliant with FINRA’s rules and any letters, filings or other supplemental information provided to FINRA pursuant to

FINRA Rules or NASD Conduct Rules is true, complete and correct in all material respects. The Company meets the definition

of the term “experienced issuer” specified in FINRA Rule 5110(j)(6).

(ff)            Parties

to Lock-Up Agreements. The Company has furnished to the Underwriters a letter agreement in the form attached hereto as Exhibit A

(the “Lock-up Agreement”) from each of the persons listed on Exhibit B. Such Exhibit B lists

under an appropriate caption the directors and officers of the Company. If any additional persons shall become directors or officers

of the Company prior to the end of the Lock-up Period (as defined below), the Company shall cause each such person, prior to or contemporaneously

with their appointment or election as a director or officer of the Company, to execute and deliver to the Representatives a Lock-up Agreement.

(gg)          Statistical

and Market-Related Data. All statistical, demographic and market-related data included or incorporated by reference in the Registration

Statements, the Time of Sale Prospectus or the Prospectus are based on or derived from sources that the Company believes, after reasonable

inquiry, to be reliable and accurate in all material respects. To the extent required, the Company has obtained the written consent to

the use of such data from such sources.

(hh)          Sarbanes-Oxley

Act. There is, and has been, no failure on the part of the Company or any of the Company’s directors or officers, in their

capacities as such, to comply with any applicable provision of the Sarbanes-Oxley Act of 2002, as amended and the rules and regulations

promulgated in connection therewith (the “Sarbanes-Oxley Act”), including Section 402 related to loans and Sections

302 and 906 related to certifications.

(ii)            No

Unlawful Contributions or Other Payments. Neither the Company nor any of its subsidiaries nor, to the best of the Company’s

knowledge, any employee or agent of the Company or any subsidiary, has made any contribution or other payment to any official of, or

candidate for, any federal, state or foreign office in violation of any law or of the character required to be disclosed in the Registration

Statements, the Time of Sale Prospectus or the Prospectus.

(jj)            Anti-Corruption

and Anti-Bribery Laws. (A) None of the Company, any of its subsidiaries or affiliates, or any director, officer or employee

thereof, or, to the Company’s knowledge, any agent or representative of the Company or of any of its subsidiaries or affiliates,

has taken or will take any action in furtherance of an offer, payment, promise to pay, or authorization or approval of the payment, giving

or receipt of money, property, gifts or anything else of value, directly or indirectly, to any government official (including any officer

or employee of a government or government-owned or controlled entity or of a public international organization, or any person acting

in an official capacity for or on behalf of any of the foregoing, or any political party or party official or candidate for political

office) in order to influence official action, or to any person in violation of any applicable anti-corruption laws; (B) the Company

and each of its subsidiaries and affiliates have conducted their respective businesses in compliance with applicable anti-corruption

laws and have instituted and maintained and will continue to maintain policies and procedures designed to promote and achieve compliance

with such laws and with the representations and warranties contained herein; and (C) neither the Company nor any of its subsidiaries

will use, directly or indirectly, the proceeds of the offering in furtherance of an offer, payment, promise to pay, or authorization

of the payment or giving of money, or anything else of value, to any person in violation of any applicable anti-corruption laws.

(kk)         Money

Laundering Laws. The operations of the Company and each of its subsidiaries are and have been conducted at all times in compliance

with applicable financial recordkeeping and reporting requirements, including those of the Bank Secrecy Act, as amended by Title III

of the Uniting and Strengthening America by Providing Appropriate Tools Required to Intercept and Obstruct Terrorism Act of 2001 (USA

PATRIOT Act), and the applicable anti-money laundering statutes of all applicable jurisdictions, the rules and regulations thereunder

and any related or similar rules, regulations or guidelines, issued, administered or enforced by any governmental agency (collectively,

the “Anti-Money Laundering Laws”), and no action, suit or proceeding by or before any court or governmental agency,

authority or body or any arbitrator involving the Company or any of its subsidiaries with respect to the Anti-Money Laundering Laws is

pending or, to the best knowledge of the Company, threatened.

(ll)           Sanctions.

(A) None of the Company, any of its subsidiaries, or any director, officer, or employee thereof, or, to the Company’s

knowledge, any agent, affiliate or representative of the Company or any of its subsidiaries, is an individual or entity (“Person”)

that is, or is 50% or greater owned or, as applicable, controlled by one or more Persons that are:

(I)            the

subject of any sanctions administered or enforced by the U.S. Department of the Treasury’s Office of Foreign Assets Control, the

United Nations Security Council, the European Union, His Majesty’s Treasury, or other relevant sanctions authority (collectively,

“Sanctions”), or

(II)           located,

organized or ordinarily resident in a country or territory that is the subject or target of Sanctions (including, without limitation,

Crimea, Cuba, Iran, North Korea, Syria, so-called Donetsk People’s Republic, and so-called Luhansk People’s Republic

regions of Ukraine, each a “Sanctioned Country”).

(B)            The

Company will not, directly or indirectly, use the proceeds of this offering, or lend, contribute or otherwise make available such proceeds

to any subsidiary, joint venture partner or other Person:

(I)            to

fund or facilitate any activities or business of or with any Person or in any country or territory that, at the time of such funding

or facilitation, is the subject or target of Sanctions; or

(II)           in

any other manner that will result in a violation of Sanctions by any Person (including any Person participating in the transaction, whether

as underwriter, advisor, investor or otherwise).

Company and each of its subsidiaries have not knowingly engaged in, are not now knowingly engaged in, and will not engage in, any dealings

or transactions with any Person, or in any country or territory, that at the time of the dealing or transaction is or was the subject

or target of Sanctions.

(mm)        Brokers.

Except pursuant to this Agreement, there is no broker, finder or other party that is entitled to receive from the Company any brokerage

or finder’s fee or other fee or commission as a result of any transactions contemplated by this Agreement.

(nn)          Forward-Looking

Statements. Each financial or operational projection or other “forward-looking statement” (as defined by Section 27A

of the Securities Act or Section 21E of the Exchange Act) contained in the Registration Statements, the Time of Sale Prospectus

or the Prospectus (i) was so included by the Company in good faith and with reasonable basis after due consideration by the Company

of the underlying assumptions, estimates and other applicable facts and circumstances and (ii) is accompanied by meaningful cautionary

statements identifying those factors that could cause actual results to differ materially from those in such forward-looking statement.

No such statement was made with the knowledge of an executive officer or director of the Company that it was false or misleading.

(oo)          No

Outstanding Loans or Other Extensions of Credit. The Company does not have any outstanding extension of credit, in the form of

a personal loan, to or for any director or executive officer (or equivalent thereof) of the Company except for such extensions of credit

as are expressly permitted by Section 13(k) of the Exchange Act.

(pp)          Cybersecurity.

The Company and its subsidiaries’ information technology assets and equipment, computers, systems, networks, hardware, software,

websites, applications, and databases (collectively, “IT Systems”) are adequate for, and operate and perform in all

material respects as required in connection with the operation of the business of the Company and its subsidiaries as currently conducted,

free and clear of all material bugs, errors, defects, Trojan horses, time bombs, malware and other corruptants. The Company and its subsidiaries

have implemented and maintained commercially reasonable physical, technical and administrative controls, policies, procedures, and safeguards

to maintain and protect their material confidential information and data, including “Personal Data,” used in connection with

their businesses (collectively, “Data”) and the integrity, continuous operation, redundancy and security of

all IT Systems. “Personal Data” means (i) a natural person’s name, street address, telephone number, e-mail

address, photograph, social security number or tax identification number, driver’s license number, passport number, credit card

number, bank information, or customer or account number; (ii) any information which would qualify as “personally identifying

information” or similar term under applicable Privacy Laws; (iii) any information which would qualify as “protected

health information” under the Health Insurance Portability and Accountability Act of 1996, as amended by the Health Information

Technology for Economic and Clinical Health Act (collectively, “HIPAA”); and (iv) any other piece of information

that allows the identification of such natural person, or his or her family, or permits the collection or analysis of any data related

to an identified person’s health or sexual orientation. There have been no breaches, violations, outages or unauthorized uses of

or accesses to any IT Systems or Data, except for those that have been remedied without material cost or liability or the duty to notify

any other person, nor any incidents under internal review or investigations relating to the same. The Company and its subsidiaries are

presently in material compliance with all applicable laws or statutes and all judgments, orders, rules and regulations of any court

or arbitrator or governmental or regulatory authority, internal policies and contractual obligations relating to the privacy and security

of IT Systems and Data and to the protection of such IT Systems and Data from unauthorized use, access, misappropriation or modification.

(qq)          Compliance

with Data Privacy Laws. The Company and its subsidiaries are, and at all prior times were, in material compliance with all applicable

state, federal, and foreign data privacy and security laws and regulations, including without limitation HIPAA, the European Union General

Data Protection Regulation (“GDPR”) (EU 2016/679), and the GDPR as it forms part of United Kingdom (“UK”)

domestic law (“UK GDPR”) (collectively, the “Privacy Laws”). To ensure compliance with the Privacy

Laws, the Company and its subsidiaries have in place, comply with, and take appropriate steps reasonably designed to ensure compliance

in all material respects with their policies and procedures relating to data privacy and security and the collection, storage, use, disclosure,

handling, and analysis of Personal Data (the “Policies”). The Company and its subsidiaries have at all times made

all disclosures to users or customers required by applicable laws and regulatory rules or requirements, and none of such disclosures

made or contained in any Policy have, to the knowledge of the Company, been inaccurate or in violation of any applicable laws and regulatory

rules or requirements in any material respect. The Company further certifies that neither it nor any subsidiary: (i) has received

notice of any actual or potential liability under or relating to, or actual or potential violation of, any of the Privacy Laws, and has

no knowledge of any event or condition that would reasonably be expected to result in any such notice; (ii) is currently conducting

or paying for, in whole or in part, any investigation, remediation, or other corrective action pursuant to any Privacy Law; or (iii) is

a party to any order, decree, or agreement that imposes any obligation or liability under any Privacy Law.

(rr)           Clinical

Data and Regulatory Compliance. The preclinical tests and clinical trials, and other studies (collectively, “studies”)

involving the Company’s product candidates that are described in, or the results of which are referred to in, the Registration

Statements, the Time of Sale Prospectus or the Prospectus were and, if still pending, are being conducted in all material respects in

accordance with the protocols, procedures and controls designed and approved for such studies and with standard medical and scientific

research procedures; each description of the results of such studies is accurate and complete in all material respects and fairly presents

the data derived from such studies, and the Company and its subsidiaries have no knowledge of any other studies involving the Company’s

product candidates, the results of which are materially inconsistent with, or otherwise call into question, the results described or

referred to in the Registration Statements, the Time of Sale Prospectus or the Prospectus; the Company and its subsidiaries have made

all material filings and obtained all such approvals as may be required by the U.S. Food and Drug Administration of the U.S. Department

of Health and Human Services or from any other U.S. or foreign government or drug or medical device regulatory agency, or health care

facility Institutional Review Board or Ethics Committee (collectively, the “Regulatory Agencies”); neither the Company

nor any of its subsidiaries has received any written notice of, or correspondence from, any Regulatory Agency requiring the termination,

suspension or modification of any clinical trials that are described or referred to in the Registration Statements, the Time of Sale

Prospectus or the Prospectus; and the Company and its subsidiaries have each operated and currently are in compliance in all material

respects with all applicable laws, rules and regulations of the Regulatory Agencies.

(ss)          Compliance

with Health Care Laws. The Company and its subsidiaries are, and at all times have been, in compliance in all material respects

with all Health Care Laws, as applicable. For purposes of this Agreement, “Health Care Laws” means: (i) the Federal

Food, Drug, and Cosmetic Act (21 U.S.C. Section 301 et seq.), the Public Health Service Act (42 U.S.C. Section 201 et seq.),

and the regulations promulgated thereunder; (ii) all applicable federal, state, local and foreign health care fraud and abuse laws,

including, without limitation, the Anti-Kickback Statute (42 U.S.C. Section 1320a-7b(b)), the Civil False Claims Act (31 U.S.C.

Section 3729 et seq.), the criminal false statements law (42 U.S.C. Section 1320a-7b(a)), 18 U.S.C. Sections 286 and 287, the

health care fraud criminal provisions under HIPAA (42 U.S.C. Section 1320d et seq.), the Stark Law (42 U.S.C. Section 1395nn),

the civil monetary penalties law (42 U.S.C. Section 1320a-7a), the exclusion law (42 U.S.C. Section 1320a-7), and applicable

laws governing government funded or sponsored healthcare programs; (iii) HIPAA, as amended by the Health Information Technology

for Economic and Clinical Health Act (42 U.S.C. Section 17921 et seq.); (iv) the Patient Protection and Affordable Care Act

of 2010, as amended by the Health Care and Education Reconciliation Act of 2010; (v) licensure, quality, safety and accreditation

requirements under applicable federal, state, local or foreign laws or regulatory bodies; and (vi) all other local, state, federal,

national, supranational and foreign laws, relating to the regulation of the product candidates of the Company or its subsidiaries, and

(vii) the directives and regulations promulgated pursuant to such statutes. Neither the Company nor any of its subsidiaries has

received written notice of any claim, action, suit, proceeding, hearing, enforcement, investigation, arbitration or other action from

any court or arbitrator or governmental or regulatory authority or third party alleging that any product operation or activity is in

violation of any Health Care Laws nor, to the Company’s knowledge, is any such claim, action, suit, proceeding, hearing, enforcement,

investigation, arbitration or other action threatened. The Company and each of the subsidiaries possesses all licenses, certificates,

authorizations and permits issued by, and has made all declarations and filings with, the appropriate local, state, federal or foreign

regulatory agencies or bodies (including, without limitation, those administered by the FDA or by any foreign, federal, state or local

governmental or regulatory authority performing functions similar to those performed by the FDA) which are necessary for the ownership

of their respective properties or the conduct of their respective businesses (collectively, the “Governmental Authorizations”).

The Company and the subsidiaries are in material compliance with all such Governmental Authorizations and all such Governmental Authorizations

are valid and in full force. Neither the Company nor any Subsidiary has received written notification of any revocation, modification

in any material respect, suspension, termination or invalidation (or proceedings related thereto) of any such Governmental Authorizations

and to the knowledge of the Company, no event has occurred that allows or results in, or after notice or lapse of time or both would

allow or result in revocation, material modification, suspension, termination or invalidation (or proceedings related thereto) of any

such Governmental Authorization and the Company has no reason to believe that any such Governmental Authorization will not be renewed.

The Company and its subsidiaries have filed, maintained or submitted all material reports, documents, forms, notices, applications, records,

claims, submissions and supplements or amendments as required by any Health Care Laws and Governmental Authorizations, and all such reports,

documents, forms, notices, applications, records, claims, submissions and supplements or amendments were complete and accurate on the

date filed in all material respects (or were corrected or supplemented by a subsequent submission). Neither the Company nor any of its

subsidiaries is a party to any corporate integrity agreements, monitoring agreements, consent decrees, settlement orders, or similar

agreements with or imposed by any governmental or regulatory authority. Additionally, neither the Company, any of its subsidiaries nor

any of their respective employees, officers, directors, or agents has been excluded, suspended or debarred from participation in any

U.S. federal health care program or human clinical research or, to the knowledge of the Company, is subject to a governmental inquiry,

investigation, proceeding, or other similar action that could reasonably be expected to result in debarment, suspension, or exclusion.

(tt)            No

Rights to Purchase Preferred Stock. The issuance and sale of the Offered Securities as contemplated hereby will not cause any

holder of any shares of capital stock, securities convertible into or exchangeable or exercisable for capital stock or options, warrants

or other rights to purchase capital stock or any other securities of the Company to have any right to acquire any shares of preferred

stock of the Company.

(uu)          No

Contract Terminations. Neither the Company nor any of its subsidiaries has sent or received any communication regarding termination

of, or intent not to renew, any of the contracts or agreements referred to or described in any preliminary prospectus, the Prospectus

or any free writing prospectus, or referred to or described in, or filed as an exhibit to, the Registration Statements, or any document

incorporated by reference therein, and no such termination or non-renewal has been threatened by the Company or any of its subsidiaries

or, to the Company’s knowledge, any other party to any such contract or agreement, which threat of termination or non-renewal has

not been rescinded as of the date hereof.

(vv)           Dividend

Restrictions. No subsidiary of the Company is prohibited or restricted, directly or indirectly, from paying dividends to the

Company, or from making any other distribution with respect to such subsidiary’s equity securities or from repaying to the Company

or any other subsidiary of the Company any amounts that may from time to time become due under any loans or advances to such subsidiary

from the Company or from transferring any property or assets to the Company or to any other subsidiary.

(ww)         Outbound

Investment Security Program. Neither the Company nor any of its subsidiaries is a “covered foreign person,” as that

term is defined in 31 C.F.R. § 850.209. Neither the Company nor any of its subsidiaries currently engages, or has plans to engage,

directly or indirectly, in a “covered activity,” as that term is defined in in 31 C.F.R. § 850.208 (“Covered

Activity”). The Company does not have any joint ventures that engage in or plan to engage in any Covered Activity. The Company

also does not, directly or indirectly, hold a board seat on, have a voting or equity interest in, or have any contractual power to direct

or cause the direction of the management or policies of any person or persons that engages or plans to engage in any Covered Activity.

Any certificate signed by any officer of the Company

or any of its subsidiaries and delivered to any Underwriter or to counsel for the Underwriters in connection with the offering, or the

purchase and sale, of the Offered Securities shall be deemed a representation and warranty by the Company to each Underwriter as to the

matters covered thereby.

The Company has a reasonable basis for making

each of the representations set forth in this Section 1. The Company acknowledges that the Underwriters and, for purposes of the

opinions to be delivered pursuant to Section 6 hereof, counsel to the Company and counsel to the Underwriters, will rely upon the

accuracy and truthfulness of the foregoing representations and hereby consents to such reliance.

Section 2.               Purchase,

Sale and Delivery of the Offered Securities.

(a)            The

Offered Securities. Upon the terms herein set forth, the Company agrees to issue and sell to the several Underwriters an aggregate

of 64,250,000 Shares, Pre-Funded Warrants to purchase an aggregate of 10,750,000 shares of Common Stock and accompanying Common Warrants

to purchase an aggregate of 75,000,000 shares of Common Stock (or Pre-Funded Warrants in lieu thereof). On the basis of the representations,

warranties and agreements herein contained, and upon the terms but subject to the conditions herein set forth, the Underwriters agree,

severally and not jointly, to purchase from the Company the respective number of Shares, Pre-Funded Warrants and accompanying Common

Warrants set forth opposite their names on Schedule A. The purchase price per Share and accompanying Common Warrant to be paid

by the several Underwriters to the Company shall be $2.82 per unit, which shall be allocated as $2.8199999 per Share and $0.0000001 per

Common Warrant (the “Share Purchase Price”) and the purchase price per Pre-Funded Warrant and accompanying Common

Warrant to be paid by the several Underwriters to the Company shall be $2.819, which shall be allocated as $2.8189999 per Pre-Funded

Warrant and $0.0000001 per Common Warrant (the “Warrant Purchase Price”).

(b)            The

Closing Date. Delivery of certificates for the Offered Securities to be purchased by the Underwriters and payment therefor shall

be made at the offices of Cooley LLP (or such other place as may be agreed to by the Company and the Representatives) at 9:00 a.m. New

York City time, on April 24, 2026 or such other time and date not later than 1:30 p.m. New York City time, on May 1,

2026 as the Representatives shall designate by notice to the Company (the time and date of such closing are called the “Closing

Date”). The Company hereby acknowledges that circumstances under which the Representatives may provide notice to postpone the

Closing Date as originally scheduled include, but are not limited to, any determination by the Company or the Representatives to recirculate

to the public copies of an amended or supplemented Prospectus or a delay as contemplated by the provisions of Section 11.

of the Offered Securities. The Representatives hereby advise the Company that the Underwriters intend to offer for sale to the

purchasers, initially on the terms set forth in the Registration Statements, the Time of Sale Prospectus and the Prospectus, their respective

portions of the Offered Securities as soon after this Agreement has been executed as the Representatives, in their sole judgment, have

determined is advisable and practicable.

(d)            Payment

for the Offered Securities. Payment for the Offered Securities shall be made at the Closing Date by wire transfer of immediately

available funds to the order of the Company. It is understood that the Representatives have been authorized, for their own accounts and

the accounts of the several Underwriters, to accept delivery of and receipt for, and make payment of the purchase price for, the Shares,

the Pre-Funded Warrants and the accompanying Common Warrants, the Underwriters have agreed to purchase. Each of Leerink Partners and

Barclays, individually and not as the Representatives of the Underwriters, may (but shall not be obligated to) make payment for any Offered

Securities to be purchased by any Underwriter whose funds shall not have been received by the Representatives by the Closing Date for

the account of such Underwriter, but any such payment shall not relieve such Underwriter from any of its obligations under this Agreement.

(e)            Delivery

of the Offered Securities. The Company shall (i) deliver, or cause to be delivered through the facilities of Depositary

Trust Company (“DTC”) unless the Representatives shall otherwise instruct, to the Representatives for the accounts

of the several Underwriters the Shares at the Closing Date and (ii) deliver, or cause to be delivered, to the Representatives or

to the purchasers thereof the Pre-Funded Warrants and Common Warrants in definitive form, in accordance with the Underwriters’

instruction at the Closing Date, in each case, against release of a wire transfer of immediately available funds for the amount of the

purchase price therefor. If the Representatives so elect, delivery of the Offered Securities may be made by credit to the accounts designated

by the Representatives through DTC’s full fast transfer or DWAC programs. The Offered Securities shall be registered in such names

and denominations as the Representatives shall have requested at least one full business days prior to the Closing Date. Time shall be

of the essence, and delivery at the time and place specified in this Agreement is a further condition to the obligations of the Underwriters.

Notwithstanding the foregoing, the Company and the Representatives shall instruct purchasers of the Pre-Funded Warrants to make payment

for the Pre-Funded Warrants and accompanying Common Warrants on the Closing Date to the Company by wire transfer in immediately available

funds to the account specified by the Company at a purchase price of $2.999 per Pre-Funded Warrant and accompanying Common Warrant, in

lieu of payment by the Underwriters for such Pre-Funded Warrants and accompanying Common Warrants, and the Company shall deliver the

Pre-Funded Warrants and accompanying Common Warrants to such purchasers on the Closing Date in definitive form against such payment,

in lieu of the Company’s obligation to deliver the Pre-Funded Warrants and accompanying Common Warrants to the Representatives;

provided that, the Underwriters shall withhold $0.18 per Pre-Funded Warrant and accompanying Common Warrant with respect to such Pre-Funded

Warrants and accompanying Common Warrant as an offset against the payment owed by the Underwriters to the Company for the Shares against

the Company’s obligation to pay the amount so withheld with respect to such Pre-Funded Warrants and accompanying Common Warrant

to the Underwriters. In the event that any purchaser of the Pre-Funded Warrants and accompanying Common Warrant fails to make payment

to the Company for all or part of the Pre-Funded Warrants and accompanying Common Warrant on the Closing Date, the Representatives shall

either (i) make payment to the Company for such Pre-Funded Warrants and accompanying Common Warrant at the Warrant Purchase Price

or (ii) elect, by written notice to the Company, to receive Shares at the Share Purchase Price in lieu of all or a portion of such

Pre-Funded Warrants and accompanying Common Warrant contemplated to be sold under this Agreement.

Section 3.               Additional

Covenants

The Company further covenants and agrees with

each Underwriter as follows:

(a)            Delivery

of Registration Statements, Time of Sale Prospectus and Prospectus. The Company shall furnish to you in New York City, without

charge, prior to 10:00 a.m. New York City time on the first business day following the date of this Agreement and during the period

when a prospectus relating to the Offered Securities is required by the Securities Act to be delivered (whether physically or through

compliance with Rule 172 under the Securities Act or any similar rule) in connection with sales of the Offered Securities, as many

copies of the Time of Sale Prospectus, the Prospectus and any supplements and amendments thereto or to the Registration Statements as

you may reasonably request.

(b)            Representatives’

Review of Proposed Amendments and Supplements. During the period when a prospectus relating to the Offered Securities is required

by the Securities Act to be delivered (whether physically or through compliance with Rule 172 under the Securities Act or any similar

rule), the Company (i) will furnish to the Representatives for review, a reasonable period of time prior to the proposed time of

filing of any proposed amendment or supplement to either registration statement comprising the Registration Statement, a copy of each

such amendment or supplement and (ii) will not amend or supplement either registration statement comprising the Registration Statement

(including any amendment or supplement through incorporation of any report filed under the Exchange Act) without the Representatives’

prior written consent, which will not be unreasonably withheld, conditioned or delayed. Prior to amending or supplementing any preliminary

prospectus, the Time of Sale Prospectus or the Prospectus (including any amendment or supplement through incorporation of any report

filed under the Exchange Act), the Company shall furnish to the Representatives for review, a reasonable amount of time prior to the

time of filing or use of the proposed amendment or supplement, a copy of each such proposed amendment or supplement. The Company shall

not file or use any such proposed amendment or supplement without the Representatives’ prior written consent, which will not be

unreasonably withheld, conditioned or delayed. The Company shall file with the Commission within the applicable period specified in Rule 424(b) under

the Securities Act any prospectus required to be filed pursuant to such Rule.

Writing Prospectuses. The Company shall furnish to the Representatives for review, a reasonable amount of time prior to the proposed

time of filing or use thereof, a copy of each proposed free writing prospectus or any amendment or supplement thereto prepared by or

on behalf of, used by, or referred to by the Company, and the Company shall not file, use or refer to any proposed free writing prospectus

or any amendment or supplement thereto without the Representatives’ prior written consent, which will not be unreasonably withheld,

conditioned or delayed. The Company shall furnish to each Underwriter, without charge, as many copies of any free writing prospectus

prepared by or on behalf of, used by or referred to by the Company as such Underwriter may reasonably request. If at any time when a

prospectus is required by the Securities Act to be delivered (whether physically or through compliance with Rule 172 under the Securities

Act or any similar rule) in connection with sales of the Offered Securities (but in any event if at any time through and including the

Closing Date) there occurred or occurs an event or development as a result of which any free writing prospectus prepared by or on behalf

of, used by, or referred to by the Company conflicted or would conflict with the information contained in the Registration Statements

or included or would include an untrue statement of a material fact or omitted or would omit to state a material fact necessary in order

to make the statements therein, in light of the circumstances prevailing at such time, not misleading, the Company shall promptly amend

or supplement such free writing prospectus to eliminate or correct such conflict or so that the statements in such free writing prospectus

as so amended or supplemented will not include an untrue statement of a material fact or omit to state a material fact necessary in order

to make the statements therein, in light of the circumstances prevailing at such time, not misleading, as the case may be; provided,

however, that prior to amending or supplementing any such free writing prospectus, the Company shall furnish to the Representatives

for review, a reasonable amount of time prior to the proposed time of filing or use thereof, a copy of such proposed amended or supplemented

free writing prospectus, and the Company shall not file, use or refer to any such amended or supplemented free writing prospectus without

the Representatives’ prior written consent, which will not be unreasonably withheld, conditioned or delayed.

(d)            Filing

of Underwriter Free Writing Prospectuses. The Company shall not take any action that would result in an Underwriter or the Company

being required to file with the Commission pursuant to Rule 433(d) under the Securities Act a free writing prospectus prepared

by or on behalf of such Underwriter that such Underwriter otherwise would not have been required to file thereunder.

(e)            Amendments

and Supplements to Time of Sale Prospectus. If the Time of Sale Prospectus is being used to solicit offers to buy the Offered

Securities at a time when the Prospectus is not yet available to prospective purchasers, and any event shall occur or condition exist

as a result of which it is necessary to amend or supplement the Time of Sale Prospectus so that the Time of Sale Prospectus does not

include an untrue statement of a material fact or omit to state a material fact necessary in order to make the statements therein, in

light of the circumstances when delivered to a prospective purchaser, not misleading, or if any event shall occur or condition exist

as a result of which the Time of Sale Prospectus conflicts with the information contained in the Registration Statements, or if, in the

opinion of counsel for the Underwriters, it is necessary to amend or supplement the Time of Sale Prospectus to comply with applicable

law, the Company shall (subject to Section 3(b) and Section 3(c) hereof) promptly prepare, file with the Commission

and furnish, at its own expense, to the Underwriters and to any dealer upon request, either amendments or supplements to the Time of

Sale Prospectus so that the statements in the Time of Sale Prospectus as so amended or supplemented will not include an untrue statement

of a material fact or omit to state a material fact necessary in order to make the statements therein, in light of the circumstances

when delivered to a prospective purchaser, not misleading or so that the Time of Sale Prospectus, as amended or supplemented, will no

longer conflict with the information contained in the Registration Statements, or so that the Time of Sale Prospectus, as amended or

supplemented, will comply with applicable law.

(f)            Certain

Notifications and Required Actions. After the date of this Agreement, the Company shall promptly advise the Representatives in

writing of: (i) the receipt of any comments of, or requests for additional or supplemental information from, the Commission; (ii) the

time and date of any filing of any post-effective amendment to the Registration Statements or any amendment or supplement to any preliminary

prospectus, the Time of Sale Prospectus, any free writing prospectus or the Prospectus; (iii) the time and date that any post-effective

amendment to the Registration Statements becomes effective; and (iv) the issuance by the Commission of any stop order suspending

the effectiveness of either registration statement comprising the Registration Statements or any post-effective amendment thereto or

any amendment or supplement to any preliminary prospectus, the Time of Sale Prospectus or the Prospectus or of any order preventing or

suspending the use of any preliminary prospectus, the Time of Sale Prospectus, any free writing prospectus or the Prospectus, or of any

proceedings to remove, suspend or terminate from listing or quotation the Common Stock from any securities exchange upon which they are

listed for trading or included or designated for quotation, or of the threatening or initiation of any proceedings for any of such purposes.

If the Commission shall enter any such stop order at any time, the Company will use its best efforts to obtain the lifting of such order

at the earliest possible moment. Additionally, the Company agrees that it shall comply with all applicable provisions of Rule 424(b),

Rule 433 and Rule 430B under the Securities Act and will use its reasonable efforts to confirm that any filings made by the

Company under Rule 424(b) or Rule 433 were received in a timely manner by the Commission.

(g)            Amendments

and Supplements to the Prospectus and Other Securities Act Matters. If any event shall occur or condition exist as a result of

which it is necessary to amend or supplement the Prospectus so that the Prospectus does not include an untrue statement of a material

fact or omit to state a material fact necessary in order to make the statements therein, in light of the circumstances when the Prospectus

is delivered (whether physically or through compliance with Rule 172 under the Securities Act or any similar rule) to a purchaser,

not misleading, or if in the opinion of the Representatives or counsel for the Underwriters it is otherwise necessary to amend or supplement

the Prospectus to comply with applicable law, the Company agrees (subject to Section 3(b) and Section 3(c)) hereof to

promptly prepare, file with the Commission and furnish, at its own expense, to the Underwriters and to any dealer upon request, amendments

or supplements to the Prospectus so that the statements in the Prospectus as so amended or supplemented will not include an untrue statement

of a material fact or omit to state a material fact necessary in order to make the statements therein, in light of the circumstances

when the Prospectus is delivered (whether physically or through compliance with Rule 172 under the Securities Act or any similar

rule) to a purchaser, not misleading or so that the Prospectus, as amended or supplemented, will comply with applicable law. Neither

the Representatives’ consent to, nor delivery of, any such amendment or supplement shall constitute a waiver of any of the Company’s

obligations under Section 3(b) or Section 3(c).

(h)            Blue

Sky Compliance. The Company shall cooperate with the Representatives and counsel for the Underwriters to qualify or register

the Offered Securities for sale under (or obtain exemptions from the application of) the state securities or blue sky laws or Canadian

provincial securities laws (or other foreign laws) of those jurisdictions designated by the Representatives, shall comply with such laws

and shall continue such qualifications, registrations and exemptions in effect so long as required for the distribution of the Offered

Securities. The Company shall not be required to qualify as a foreign corporation or to take any action that would subject it to general

service of process in any such jurisdiction where it is not presently qualified or where it would be subject to taxation as a foreign

corporation. The Company will advise the Representatives promptly of the suspension of the qualification or registration of (or any such

exemption relating to) the Offered Securities for offering, sale or trading in any jurisdiction or any initiation or threat of any proceeding

for any such purpose, and in the event of the issuance of any order suspending such qualification, registration or exemption, the Company

shall use its best efforts to obtain the withdrawal thereof at the earliest possible moment.

(i)            Use

of Proceeds. The Company shall apply the net proceeds from the sale of the Offered Securities sold by it substantially in the

manner described under the caption “Use of Proceeds” in the Registration Statements, the Time of Sale Prospectus and the

Prospectus.

(j)            Transfer

Agent. The Company shall engage and maintain, at its expense, a registrar and transfer agent for the Shares and the Warrant Shares.

(k)            Earnings

Statement. The Company will make generally available to its security holders and to the Representatives as soon as practicable

an earnings statement (which need not be audited) covering a period of at least twelve months beginning with the first fiscal quarter

of the Company commencing after the date of this Agreement that will satisfy the provisions of Section 11(a) of the Securities

Act and the rules and regulations of the Commission thereunder.

(l)            Continued

Compliance with Securities Laws. The Company will comply with the Securities Act and the Exchange Act so as to permit the completion

of the distribution of the Offered Securities as contemplated by this Agreement, the Registration Statements, the Time of Sale Prospectus

and the Prospectus. Without limiting the generality of the foregoing, the Company will, during the period when a prospectus relating

to the Offered Securities is required by the Securities Act to be delivered (whether physically or through compliance with Rule 172

under the Securities Act or any similar rule), file on a timely basis with the Commission and Nasdaq all reports and documents required

to be filed under the Exchange Act.

(m)            Listing.

The Company will use its best efforts to list, subject to notice of issuance, the Shares and the Warrant Shares on Nasdaq.

(n)            Company

to Provide Copy of the Prospectus in Form That May be Downloaded from the Internet. If requested by the Representatives,

the Company shall cause to be prepared and delivered, at its expense, within one business day from the effective date of this Agreement,

to the Representatives an “electronic Prospectus” to be used by the Underwriters in connection with the offering and

sale of the Offered Securities. As used herein, the term “electronic Prospectus” means a form of Prospectus, and any

amendment or supplement thereto, that meets each of the following conditions: (i) it shall be encoded in an electronic format, satisfactory

to the Representatives, that may be transmitted electronically by the Representatives and the other Underwriters to offerees and purchasers

of the Offered Securities; (ii) it shall disclose the same information as the paper Prospectus, except to the extent that graphic

and image material cannot be disseminated electronically, in which case such graphic and image material shall be replaced in the electronic

Prospectus with a fair and accurate narrative description or tabular representation of such material, as appropriate; and (iii) it

shall be in or convertible into a paper format or an electronic format, satisfactory to the Representatives, that will allow investors

to store and have continuously ready access to the Prospectus at any future time, without charge to investors (other than any fee charged

for subscription to the Internet as a whole and for on-line time). The Company hereby confirms that it has included or will include in

the Prospectus filed pursuant to EDGAR or otherwise with the Commission and in the Registration Statements at the time it was declared

effective an undertaking that, upon receipt of a request by an investor or his or her representative, the Company shall transmit or cause

to be transmitted promptly, without charge, a paper copy of the Prospectus.

(o)            Agreement

Not to Offer or Sell Additional Shares. During the period commencing on and including the date hereof and continuing through

and including the 90th day following the date of the Prospectus (such period, as extended as described below, being referred to herein

as the “Lock-up Period”), the Company will not, without the prior written consent of Leerink Partners and Barclays

(which consent may be withheld in their sole discretion), directly or indirectly: (i) sell, offer to sell, contract to sell or lend

any Common Stock or Related Securities (as defined below); (ii) effect any short sale, or establish or increase any “put equivalent

position” (as defined in Rule 16a-1(h) under the Exchange Act) or liquidate or decrease any “call equivalent position”

(as defined in Rule- 16a-1(b) under the Exchange Act) of any Common Stock or Related Securities; (iii) pledge, hypothecate

or grant any security interest in any Common Stock or Related Securities; (iv) in any other way transfer or dispose of any Common

Stock or Related Securities; (v) enter into any swap, hedge or similar arrangement or agreement that transfers, in whole or in part,

the economic risk of ownership of any Common Stock or Related Securities, regardless of whether any such transaction is to be settled

in securities, in cash or otherwise; (vi) announce the offering of any shares of Common Stock or Related Securities (other than

as contemplated by this Agreement with respect to the Offered Securities and the Warrant Shares); (vii) submit or file any registration

statement under the Securities Act in respect of any Common Stock or Related Securities (other than as contemplated by this Agreement

with respect to the Offered Securities and the Warrant Shares); (viii) effect a reverse stock split, recapitalization, share consolidation,

reclassification or similar transaction affecting the outstanding Common Stock; or (ix) publicly announce the intention to do any

of the foregoing; provided, however, that the Company may (A) effect the transactions contemplated hereby (including the

issuance of Warrant Shares upon exercise of the Warrants), (B) issue shares of Common Stock or options to purchase shares of Common

Stock, or issue shares of Common Stock upon exercise of options, pursuant to any stock option, stock bonus or other stock plan or arrangement

described in the Registration Statements, the Time of Sale Prospectus and the Prospectus, (C) file one or more registration statements

on Form S-8, (D) issue and sell shares pursuant to the Equity Distribution Agreement, dated November 6, 2025, by and between

the Company and Leerink Partners, following the date that is 30 days following the date of the Prospectus and (E) offer, or issue

securities exercisable or exchangeable for, shares of Common Stock in connection with any merger, acquisition or strategic investment

(including any joint venture, strategic alliance or partnership) as long as (x) the aggregate number of shares of Common Stock issued

or issuable does not exceed 5.0% of the number of shares of Common Stock outstanding immediately after the issuance and sale of the Offered

Securities (after giving effect to the Warrant Shares issuable upon the exercise of the Warrants) and (y) each recipient of any

such shares of Common Stock issued or issuable agrees to the restrictions on the resale of securities that are consistent with the lock-up

letters described in Section 6(i) hereof for the remainder of the Lock-up Period. For purposes of the foregoing, “Related

Securities” shall mean any options or warrants or other rights to acquire shares of Common Stock or any securities exchangeable

or exercisable for or convertible into shares of Common Stock, or to acquire other securities or rights ultimately exchangeable or exercisable

for, or convertible into, shares of Common Stock.

(p)            Future

Reports to the Representatives. During the period of five years hereafter, the Company will furnish to the Representatives: (i) as

soon as practicable after the end of each fiscal year, copies of the Annual Report of the Company containing the balance sheet of the

Company as of the close of such fiscal year and statements of income, stockholders’ equity and cash flows for the year then ended

and the opinion thereon of the Company’s independent public or certified public accountants; (ii) as soon as practicable after

the filing thereof, copies of each proxy statement, Annual Report on Form 10-K, Quarterly Report on Form 10-Q, Current Report

on Form 8-K or other report filed by the Company with the Commission, FINRA or any securities exchange; and (iii) as soon as

available, copies of any report or communication of the Company furnished or made available generally to holders of its capital stock;

provided, however, that the requirements of this Section 3(p) shall be satisfied to the extent that such reports, statement,

communications, financial statements or other documents are available on EDGAR.

(q)            Investment

Limitation. The Company shall not invest or otherwise use the proceeds received by the Company from its sale of the Offered Securities

in such a manner as would require the Company or any of its subsidiaries to register as an investment company under the Investment Company

Act.

(r)            No

Stabilization or Manipulation; Compliance with Regulation M. The Company will not take, and will ensure that no affiliate of

the Company will take, directly or indirectly, any action designed to or that might cause or result in stabilization or manipulation

of the price of the Common Stock or any reference security with respect to the Common Stock, whether to facilitate the sale or resale

of the Offered Securities or otherwise, and the Company will, and shall cause each of its affiliates to, comply with all applicable provisions

of Regulation M.

(s)            Enforce

Lock-Up Agreements. During the Lock-up Period, the Company will enforce all agreements between the Company and any of its securityholders

that restrict or prohibit, expressly or in operation, the offer, sale or transfer of Common Stock or Related Securities or any of the

other actions restricted or prohibited under the terms of the form of Lock-up Agreement. In addition, the Company will direct the transfer

agent to place stop transfer restrictions upon any such securities of the Company that are bound by such “lock-up” agreements

for the duration of the periods contemplated in such agreements, including, without limitation, “lock-up” agreements entered

into by the Company’s officers and directors pursuant to Section 6(i) hereof.

(t)            Company

to Provide Interim Financial Statements. Prior to the Closing Date, the Company will furnish the Underwriters, as soon as they

have been prepared by or are available to the Company, a copy of any unaudited interim financial statements of the Company for any period

subsequent to the period covered by the most recent financial statements appearing in the Registration Statements and the Prospectus,

provided, however, that the requirements of this Section 3(t) shall be satisfied to the extent that such financial statements

are available on EDGAR.

(u)            Warrant

Shares Reserved. The Company shall, at all times while any Warrants are outstanding, reserve and keep available out of its authorized

but unissued and otherwise unreserved shares of Common Stock, solely for the purpose of enabling it to issue Warrant Shares upon exercise

of such Warrants, the number of Warrant Shares that are initially issuable and deliverable upon the exercise of the then outstanding

Warrants.

(v)            Registration

Statement for Common Warrants. The Company shall, at all times while any Common Warrants are outstanding, use its commercially reasonable

efforts to maintain a registration statement covering the issue and sale of the Warrant Shares upon exercise of the Common Warrants such

that the Warrant Shares, when issued, will not be subject to resale and restrictions under the Securities Act except to the extent that

the Warrant Shares are owned by affiliates.

The Representatives, on behalf of the several

Underwriters, may, in their sole discretion, waive in writing the performance by the Company of any one or more of the foregoing covenants

or extend the time for their performance.

Section 4.               Payment

of Expenses. The Company agrees to pay all costs, fees and expenses incurred in connection with the performance of its obligations

hereunder and in connection with the transactions contemplated hereby, including without limitation (i) all expenses incident to

the issuance and delivery of the Offered Securities, including the costs of reproducing and distributing each of the Warrants, if necessary,

and the Warrant Shares (including all printing and engraving costs), (ii) all fees and expenses of the registrar and transfer agent

of the Offered Securities, including the Warrant Shares, (iii) all necessary issue, transfer, stamp and other similar taxes in connection

with the issuance and sale of the Offered Securities to the Underwriters, (iv) all fees and expenses of the Company’s counsel,

independent public or certified public accountants and other advisors, (v) all costs and expenses incurred in connection with the

preparation, printing, filing, shipping and distribution of the Registration Statements (including financial statements, exhibits, schedules,

consents and certificates of experts), the Time of Sale Prospectus, the Prospectus, each free writing prospectus prepared by or on behalf

of, used by, or referred to by the Company, and each preliminary prospectus and all amendments and supplements thereto, and this Agreement,

(vi) all filing fees, attorneys’ fees and expenses incurred by the Company or the Underwriters in connection with qualifying

or registering (or obtaining exemptions from the qualification or registration of) all or any part of the Offered Securities for offer

and sale under the state securities or blue sky laws or the provincial securities laws of Canada, and, if requested by the Representatives,

preparing and printing a “Blue Sky Survey” or memorandum and a “Canadian wrapper”, and any supplements thereto,

advising the Underwriters of such qualifications, registrations and exemptions, in an amount not to exceed $10,000, (vii) the costs,

fees and expenses incurred by the Underwriters in connection with any FINRA filings made related to the Underwriters’ participation

in the offering and distribution of the Offered Securities, including any related filing fees and the legal fees of, and disbursements

by, counsel to the Underwriters, in an amount, together with the fees incurred in connection with (vi) above, not to exceed $15,000,

(viii) the costs and expenses of the Company relating to investor presentations on any “road show”, including, without

limitation, expenses associated with the preparation or dissemination of any electronic road show, expenses associated with the production

of road show slides and graphics, fees and expenses of any consultants engaged in connection with the road show presentations with the

prior approval of the Company, travel and lodging expenses of the representatives, employees and officers of the Company and any such

consultants, (ix) the fees and expenses associated with listing the Shares and Warrant Shares on Nasdaq, and (x) all other

fees, costs and expenses of the nature referred to in Item 14 of Part II of the Registration Statements. Except as provided in this

Section 4 or in Section 7, Section 9 or Section 10 hereof, the Underwriters shall pay their own expenses, including

the fees and disbursements of their counsel and any transfer, stamp and other similar taxes in connection with the sale of the Offered

Securities by the Underwriters.

Section 5.               Covenant

of the Underwriters. Each Underwriter severally and not jointly covenants with the Company not to take any action that would result

in the Company being required to file with the Commission pursuant to Rule 433(d) under the Securities Act a free writing prospectus

prepared by or on behalf of such Underwriter that otherwise would not, but for such actions, be required to be filed by the Company under

Rule 433(d).

Section 6.             Conditions

of the Obligations of the Underwriters. The respective obligations of the several Underwriters hereunder to purchase and pay for

the Offered Securities as provided herein on the Closing Date shall be subject to the accuracy of the representations and warranties

on the part of the Company set forth in Section 1 hereof as of the date hereof and as of the Closing Date as though then made, and

to each of the following additional conditions:

(a)            Comfort

Letter. On the date hereof, the Representatives shall have received from Ernst & Young LLP, independent registered public

accountants for the Company, a letter dated the date hereof addressed to the Underwriters, in form and substance satisfactory to the

Representatives, containing statements and information of the type ordinarily included in accountant’s “comfort letters”

to underwriters, delivered according to Statement of Auditing Standards No. 72 (or any successor bulletin), with respect to the

audited and unaudited financial statements and certain financial information contained in the Registration Statements, the Time of Sale

Prospectus, and each free writing prospectus, if any.

(b)            Compliance

with Registration Requirements; No Stop Order; No Objection from FINRA. For the period from and after the date of this Agreement

and through and including the Closing Date: (i) the Company shall have filed the Prospectus with the Commission (including the information

previously omitted from the Registration Statements pursuant to Rule 430B under the Securities Act) in the manner and within the

time period required by Rule 424(b) under the Securities Act; or the Company shall have filed a post-effective amendment to

the Registration Statements containing the information previously omitted from the Registration Statements pursuant to such Rule 430B,

and such post-effective amendment shall have become effective; and the Company shall have complied with all filing requirements applicable

to any free writing prospectus used or referred to after the date hereof; (ii) no stop order suspending the effectiveness of either

registration statement comprising the Registration Statements or any post-effective amendment thereto shall be in effect, and no proceedings

for such purpose shall have been instituted or threatened by the Commission and the Commission shall not have notified the Company of

any objection to the use of the form of either registration statement comprising the Registration Statements or any post-effective amendment

thereto; and (iii) if a filing has been made with FINRA, FINRA shall have raised no objection to the fairness and reasonableness

of the underwriting terms and arrangements.

Material Adverse Change or Ratings Agency Change. For the period from and after the date of this Agreement and through and including

the Closing Date: (i) in the judgment of the Representatives there shall not have occurred any Material Adverse Change; and (ii) there

shall not have occurred any downgrading, nor shall any notice have been given of any intended or potential downgrading or of any review

for a possible change that does not indicate the direction of the possible change, in the rating accorded any securities of the Company

or any of its subsidiaries by any “nationally recognized statistical rating organization” as that term is used in Rule 15c3-1(c)(2)(vi)(F) under

the Exchange Act.

(d)            Opinion

of Counsel for the Company. On the Closing Date, the Representatives shall have received the opinion and negative assurance letter

of Goodwin Procter LLP, counsel for the Company, dated as of such date, in the form and substance satisfactory to the Representatives.

(e)            Opinion

of Intellectual Property Counsel for the Company. On the Closing Date, the Representatives shall have received the opinion of

Duane Morris LLP, intellectual property counsel for the Company with respect to intellectual property matters, dated as of such date,

in the form and substance satisfactory to the Representatives.

(f)             Opinion

of Counsel for the Underwriters. On the Closing Date, the Representatives shall have received the opinion and negative assurance

letter of Cooley LLP, counsel for the Underwriters in connection with the offer and sale of the Offered Securities, in the form and substance

satisfactory to the Representatives.

(g)            Officers’

Certificate. On the Closing Date, the Representatives shall have received a certificate executed by the Chief Executive Officer

or President of the Company and the Chief Financial Officer of the Company, dated as of such date, to the effect set forth in Section 6(b)(ii) and

further to the effect that:

(i)            for

the period from and including the date of this Agreement through and including such date, there has not occurred any Material Adverse

Change;

(ii)           the

representations, warranties and covenants of the Company set forth in Section 1 of this Agreement are true and correct with the

same force and effect as though expressly made on and as of such date;

(iii)         the

Company has complied with all the agreements hereunder and satisfied all the conditions on its part to be performed or satisfied hereunder

at or prior to such date; and

(iv)          to

the effect of 6(c)(ii).

(h)            Bring-down

Comfort Letter. On the Closing Date, the Representatives shall have received from Ernst & Young LLP, independent registered

public accountants for the Company, a letter dated such date, in form and substance satisfactory to the Representatives, which letter

shall: (i) reaffirm the statements made in the letter furnished by them pursuant to Section 6(a), except that the specified

date referred to therein for the carrying out of procedures shall be no more than three business days prior to the Closing Date; and

(ii) cover certain financial information contained in the Prospectus.

(i)            Lock-Up

Agreements. On or prior to the date hereof, the Company shall have furnished to the Representatives an agreement in the form

of Exhibit A hereto from each of the persons listed on Exhibit B hereto, and each such agreement shall be in

full force and effect on the Closing Date.

(j)            Reserved.

(k)            Rule 462(b) Registration

Statement. In the event that a Rule 462(b) Registration Statement is filed in connection with the offering contemplated

by this Agreement, such Rule 462(b) Registration Statement shall have been filed with the Commission on the date of this Agreement

and shall have become effective automatically upon such filing.

(l)            Additional

Documents. On the Closing Date, the Representatives and counsel for the Underwriters shall have received such information, documents

and opinions as they may reasonably request for the purposes of enabling them to pass upon the issuance and sale of the Offered Securities

as contemplated herein, or in order to evidence the accuracy of any of the representations and warranties, or the satisfaction of any

of the conditions or agreements, herein contained; and all proceedings taken by the Company in connection with the issuance and sale

of the Offered Securities as contemplated herein and in connection with the other transactions contemplated by this Agreement shall be

satisfactory in form and substance to the Representatives and counsel for the Underwriters.

(m)           Form of

Warrant. The Representatives shall have received a form of each of the Pre-Funded Warrant and the Common Warrant, in form and

substance reasonably satisfactory to the Representatives.

(n)            Accurate

Disclosure. No Underwriter shall have discovered and disclosed to the Company on or prior to the Closing Date, that the Registration

Statements, the Prospectus or the Time of Sale Prospectus, or any amendment or supplement thereto, contains an untrue statement of a

fact which, in the opinion of counsel for the Underwriters, is material or omits to state a fact which, in the opinion of such counsel,

is material and is required to be stated therein or is necessary to make the statements therein not misleading.

If any condition specified in this Section 6

is not satisfied when and as required to be satisfied, this Agreement may be terminated by the Representatives by notice from the Representatives

to the Company at any time on or prior to the Closing Date, which termination shall be without liability on the part of any party to

any other party, except that Section 4, Section 7, Section 9 and Section 10 shall at all times be effective and shall

survive such termination.

Section 7.               Reimbursement

of Underwriters’ Expenses. If this Agreement is terminated by the Representatives pursuant to Section 6, Section 11

or Section 12(i) or (v), or if the sale to the Underwriters of the Offered Securities on the Closing Date is not consummated

because of any refusal, inability or failure on the part of the Company to perform any agreement herein or to comply with any provision

hereof, the Company agrees to reimburse the Representatives and the other Underwriters (or such Underwriters as have terminated this

Agreement with respect to themselves), severally, upon demand for all out-of-pocket expenses that shall have been reasonably incurred

by the Representatives and the Underwriters in connection with the proposed purchase and the offering and sale of the Offered Securities,

including, but not limited to, fees and disbursements of counsel, printing expenses, travel expenses, postage, facsimile and telephone

charges.

Section 8.               Effectiveness

of this Agreement. This Agreement shall become effective upon the execution and delivery hereof by the parties hereto.

Section 9.               Indemnification.

(a)            Indemnification

of the Underwriters. The Company agrees to indemnify and hold harmless each Underwriter, its affiliates, directors, officers,

employees and agents, and each person, if any, who controls any Underwriter within the meaning of the Securities Act or the Exchange

Act against any loss, claim, damage, liability or expense, as incurred, to which such Underwriter or such affiliate, director, officer,

employee, agent or controlling person may become subject, under the Securities Act, the Exchange Act, other federal or state statutory

law or regulation, or the laws or regulations of foreign jurisdictions where Offered Securities have been offered or sold or at common

law or otherwise (including in settlement of any litigation, if such settlement is effected with the written consent of the Company),

insofar as such loss, claim, damage, liability or expense (or actions in respect thereof as contemplated below) arises out of or is based

upon (i) any untrue statement or alleged untrue statement of a material fact contained in the Registration Statements, or any amendment

thereto, or the omission or alleged omission to state therein a material fact required to be stated therein or necessary to make the

statements therein not misleading; or (ii) any untrue statement or alleged untrue statement of a material fact included in any preliminary

prospectus, the Time of Sale Prospectus, any free writing prospectus that the Company has used, referred to or filed, or is required

to file, pursuant to Rule 433(d) of the Securities Act, any Marketing Material or the Prospectus (or any amendment or supplement

to the foregoing), or the omission or alleged omission to state therein a material fact necessary in order to make the statements, in

light of the circumstances under which they were made, not misleading; or (iii) any act or failure to act or any alleged act or

failure to act by any Underwriter in connection with, or relating in any manner to, the Offered Securities or the offering contemplated

hereby, and which is included as part of or referred to in any loss, claim, damage, liability or action arising out of or based upon

any matter covered by clause (i) or (ii) above; and to reimburse each Underwriter and each such affiliate, director, officer,

employee, agent and controlling person for any and all reasonable expenses (including the reasonable and documented fees and disbursements

of counsel) as such expenses are incurred by such Underwriter or such affiliate, director, officer, employee, agent or controlling person

in connection with investigating, defending, settling, compromising or paying any such loss, claim, damage, liability, expense or action;

provided, however, that the foregoing indemnity agreement shall not apply to any loss, claim, damage, liability or expense to

the extent, but only to the extent, arising out of or based upon any untrue statement or alleged untrue statement or omission or alleged

omission made in reliance upon and in conformity with information relating to any Underwriter furnished to the Company by the Representatives

in writing expressly for use in the Registration Statements, any preliminary prospectus, the Time of Sale Prospectus, any such free writing

prospectus, any Marketing Material or the Prospectus (or any amendment or supplement thereto), it being understood and agreed that the

only such information consists of the information described in Section 9(b) below. The indemnity agreement set forth in this

Section 9(a) shall be in addition to any liabilities that the Company may otherwise have.

(b)            Indemnification

of the Company, its Directors and Officers. Each Underwriter agrees, severally and not jointly, to indemnify and hold harmless

the Company, each of its directors, each of its officers who signed the Registration Statements and each person, if any, who controls

the Company within the meaning of the Securities Act or the Exchange Act, against any loss, claim, damage, liability or expense, as incurred,

to which the Company, or any such director, officer or controlling person may become subject, under the Securities Act, the Exchange

Act, or other federal or state statutory law or regulation, or at common law or otherwise (including in settlement of any litigation,

if such settlement is effected with the written consent of such Underwriter), insofar as such loss, claim, damage, liability or expense

(or actions in respect thereof as contemplated below) arises out of or is based upon (i) any untrue statement or alleged untrue

statement of a material fact contained in the Registration Statements, or any amendment thereto, or any omission or alleged omission

to state therein a material fact required to be stated therein or necessary to make the statements therein not misleading or (ii) any

untrue statement or alleged untrue statement of a material fact included or incorporated by reference in any preliminary prospectus,

the Time of Sale Prospectus, any free writing prospectus that the Company has used, referred to or filed, or is required to file, pursuant

to Rule 433 of the Securities Act or the Prospectus (or any such amendment or supplement) or the omission or alleged omission to

state therein a material fact necessary in order to make the statements, in light of the circumstances under which they were made, not

misleading, in each case to the extent, but only to the extent, that such untrue statement or alleged untrue statement or omission or

alleged omission was made in the Registration Statements, such preliminary prospectus, the Time of Sale Prospectus, such free writing

prospectus or the Prospectus (or any such amendment or supplement), in reliance upon and in conformity with information relating to such

Underwriter furnished to the Company by the Representatives in writing expressly for use therein; and to reimburse the Company, or any

such director, officer or controlling person for any and all reasonable expenses (including the reasonable and documented fees and disbursements

of counsel) as such expenses are incurred by the Company, or any such director, officer or controlling person in connection with investigating,

defending, settling, compromising or paying any such loss, claim, damage, liability, expense or action. The Company hereby acknowledges

that the only information that the Representatives have furnished to the Company expressly for use in the Registration Statements, any

preliminary prospectus, the Time of Sale Prospectus, any free writing prospectus that the Company has filed, or is required to file,

pursuant to Rule 433(d) of the Securities Act or the Prospectus (or any amendment or supplement to the foregoing) are the concession

figure appearing in the third paragraph under the caption “Underwriting” and the information contained in the thirteenth

paragraph under the caption “Underwriting” in the Prospectus. The indemnity agreement set forth in this Section 9(b) shall

be in addition to any liabilities that each Underwriter may otherwise have.

and Other Indemnification Procedures. Promptly after receipt by an indemnified party under this Section 9 of notice of the

commencement of any action, such indemnified party will, if a claim in respect thereof is to be made against an indemnifying party under

this Section 9, notify the indemnifying party in writing of the commencement thereof, but the omission to so notify the indemnifying

party will not relieve the indemnifying party from any liability which it may have to any indemnified party to the extent the indemnifying

party is not materially prejudiced as a proximate result of such failure and shall not in any event relieve the indemnifying party from

any liability that it may have otherwise than on account of this indemnity agreement. In case any such action is brought against any

indemnified party and such indemnified party seeks or intends to seek indemnity from an indemnifying party, the indemnifying party will

be entitled to participate in, and, to the extent that it shall elect, jointly with all other indemnifying parties similarly notified,

by written notice delivered to the indemnified party promptly after receiving the aforesaid notice from such indemnified party, to assume

the defense thereof with counsel reasonably satisfactory to such indemnified party; provided, however, that if the defendants

in any such action include both the indemnified party and the indemnifying party and the indemnified party shall have reasonably concluded

that a conflict may arise between the positions of the indemnifying party and the indemnified party in conducting the defense of any

such action or that there may be legal defenses available to it and/or other indemnified parties which are different from or additional

to those available to the indemnifying party, the indemnified party or parties shall have the right to select separate counsel to assume

such legal defenses and to otherwise participate in the defense of such action on behalf of such indemnified party or parties. Upon receipt

of notice from the indemnifying party to such indemnified party of such indemnifying party’s election to so assume the defense

of such action and approval by the indemnified party of counsel, the indemnifying party will not be liable to such indemnified party

under this Section 9 for any legal or other expenses subsequently incurred by such indemnified party in connection with the defense

thereof unless (i) the indemnified party shall have employed separate counsel in accordance with the proviso to the preceding sentence

(it being understood, however, that the indemnifying party shall not be liable for the fees and expenses of more than one separate counsel

(together with local counsel), representing the indemnified parties who are parties to such action), which counsel (together with any

local counsel) for the indemnified parties shall be selected by the Representatives (in the case of counsel for the indemnified parties

referred to in Section 9(a) above) or by the Company (in the case of counsel for the indemnified parties referred to in Section 9(b) above)

or (ii) the indemnifying party shall not have employed counsel satisfactory to the indemnified party to represent the indemnified

party within a reasonable time after notice of commencement of the action or (iii) the indemnifying party has authorized in writing

the employment of counsel for the indemnified party at the expense of the indemnifying party, in each of which cases the fees and expenses

of counsel shall be at the expense of the indemnifying party and shall be paid as they are incurred.

(d)            Settlements.

The indemnifying party under this Section 9 shall not be liable for any settlement of any proceeding effected without its written

consent, but if settled with such consent or if there be a final judgment for the plaintiff, the indemnifying party agrees to indemnify

the indemnified party against any loss, claim, damage, liability or expense by reason of such settlement or judgment. Notwithstanding

the foregoing sentence, if at any time an indemnified party shall have requested an indemnifying party to reimburse the indemnified party

for fees and expenses of counsel as contemplated by Section 9(c) hereof, the indemnifying party shall be liable for any settlement

of any proceeding effected without its written consent if (i) such settlement is entered into more than 30 days after receipt

by such indemnifying party of the aforesaid request and (ii) such indemnifying party shall not have reimbursed the indemnified party

in accordance with such request prior to the date of such settlement. No indemnifying party shall, without the prior written consent

of the indemnified party, effect any settlement, compromise or consent to the entry of judgment in any pending or threatened action,

suit or proceeding in respect of which any indemnified party is or could have been a party and indemnity was or could have been sought

hereunder by such indemnified party, unless such settlement, compromise or consent includes an unconditional release of such indemnified

party from all liability on claims that are the subject matter of such action, suit or proceeding and does not include an admission of

fault or culpability or a failure to act by or on behalf of such indemnified party.

Section 10.             Contribution.

If the indemnification provided for in Section 9 is for any reason held to be unavailable to or otherwise insufficient to hold harmless

an indemnified party in respect of any losses, claims, damages, liabilities or expenses referred to therein, then each indemnifying party

shall contribute to the aggregate amount paid or payable by such indemnified party, as incurred, as a result of any losses, claims, damages,

liabilities or expenses referred to therein (i) in such proportion as is appropriate to reflect the relative benefits received by

the Company, on the one hand, and the Underwriters, on the other hand, from the offering of the Offered Securities pursuant to this Agreement

or (ii) if the allocation provided by clause (i) above is not permitted by applicable law, in such proportion as is appropriate

to reflect not only the relative benefits referred to in clause (i) above but also the relative fault of the Company, on the

one hand, and the Underwriters, on the other hand, in connection with the statements or omissions which resulted in such losses, claims,

damages, liabilities or expenses, as well as any other relevant equitable considerations. The relative benefits received by the Company,

on the one hand, and the Underwriters, on the other hand, in connection with the offering of the Offered Securities pursuant to this

Agreement shall be deemed to be in the same respective proportions as the total proceeds from the offering of the Offered Securities

pursuant to this Agreement (before deducting expenses) received by the Company, and the total underwriting discounts and commissions

received by the Underwriters, in each case as set forth on the front cover page of the Prospectus, bear to the aggregate initial

offering price of the Offered Securities as set forth on such cover. The relative fault of the Company, on the one hand, and the Underwriters,

on the other hand, shall be determined by reference to, among other things, whether any such untrue or alleged untrue statement of a

material fact or omission or alleged omission to state a material fact relates to information supplied by the Company, on the one hand,

or the Underwriters, on the other hand, and the parties’ relative intent, knowledge, access to information and opportunity to correct

or prevent such statement or omission.

The amount paid or payable by a party as a result

of the losses, claims, damages, liabilities and expenses referred to above shall be deemed to include, subject to the limitations set

forth in Section 9(c), any legal or other fees or expenses reasonably incurred by such party in connection with investigating or

defending any action or claim. The provisions set forth in Section 9(c) with respect to notice of commencement of any action

shall apply if a claim for contribution is to be made under this Section 10; provided, however, that no additional notice

shall be required with respect to any action for which notice has been given under Section 9(c) for purposes of indemnification.

The Company and the Underwriters agree that it

would not be just and equitable if contribution pursuant to this Section 10 were determined by pro rata allocation (even if the

Underwriters were treated as one entity for such purpose) or by any other method of allocation which does not take account of the equitable

considerations referred to in this Section 10.

Notwithstanding the provisions of this Section 10,

no Underwriter shall be required to contribute any amount in excess of the underwriting discounts and commissions received by such Underwriter

in connection with the Offered Securities underwritten by it and distributed to the purchasers. No person guilty of fraudulent misrepresentation

(within the meaning of Section 11(f) of the Securities Act) shall be entitled to contribution from any person who was not guilty

of such fraudulent misrepresentation. The Underwriters’ obligations to contribute pursuant to this Section 10 are several,

and not joint, in proportion to their respective underwriting commitments as set forth opposite their respective names on Schedule

A. For purposes of this Section 10, each affiliate, director, officer, employee and agent of an Underwriter and each person,

if any, who controls an Underwriter within the meaning of the Securities Act or the Exchange Act shall have the same rights to contribution

as such Underwriter, and each director of the Company, each officer of the Company who signed any registration statement comprising the

Registration Statements, and each person, if any, who controls the Company within the meaning of the Securities Act and the Exchange

Act shall have the same rights to contribution as the Company.

Section 11.             Default

of One or More of the Several Underwriters. If, on the Closing Date, any one or more of the several Underwriters shall fail

or refuse to purchase Offered Securities that it or they have agreed to purchase hereunder on such date, and the aggregate number of

Offered Securities which such defaulting Underwriter or Underwriters agreed but failed or refused to purchase does not exceed 10% of

the aggregate number of the Offered Securities to be purchased on such date, the Representatives may make arrangements satisfactory to

the Company for the purchase of such Offered Securities by other persons, including any of the Underwriters, but if no such arrangements

are made by such date, the other Underwriters shall be obligated, severally and not jointly, in the proportions that the number of Offered

Securities set forth opposite their respective names on Schedule A bears to the aggregate number of Offered Securities set forth opposite

the names of all such non-defaulting Underwriters, or in such other proportions as may be specified by the Representatives with the consent

of the non-defaulting Underwriters, to purchase the Offered Securities which such defaulting Underwriter or Underwriters agreed but failed

or refused to purchase on such date. If, on the Closing Date, any one or more of the Underwriters shall fail or refuse to purchase Offered

Securities and the aggregate number of Offered Securities with respect to which such default occurs exceeds 10% of the aggregate number

of Offered Securities to be purchased on such date, and arrangements satisfactory to the Representatives and the Company for the purchase

of such Offered Securities are not made within 48 hours after such default, this Agreement shall terminate without liability of any party

to any other party except that the provisions of Section 4, Section 7, Section 9 and Section 10 shall at all times

be effective and shall survive such termination. In any such case either the Representatives or the Company shall have the right to postpone

the Closing Date, but in no event for longer than seven days in order that the required changes, if any, to the Registration Statements

and the Prospectus or any other documents or arrangements may be effected.

As used in this Agreement,

the term “Underwriter” shall be deemed to include any person substituted for a defaulting Underwriter under this Section 11.

Any action taken under this Section 11 shall not relieve any defaulting Underwriter from liability in respect of any default of

such Underwriter under this Agreement.

Section 12.            Termination

of this Agreement. Prior to the purchase of the Offered Securities by the Underwriters on the Closing Date, this Agreement

may be terminated by the Representatives by notice given to the Company if at any time: (i) trading or quotation in any of the Company’s

securities shall have been suspended or limited by the Commission or by Nasdaq, or trading in securities generally on either the Nasdaq

or the New York Stock Exchange shall have been suspended or limited, or minimum or maximum prices shall have been generally established

on any of such stock exchanges; (ii) a general banking moratorium shall have been declared by any of federal, New York or Maryland

authorities; (iii) there shall have occurred any outbreak or escalation of national or international hostilities or any crisis or

calamity, or any change in the United States or international financial markets, or any substantial change or development involving a

prospective substantial change in United States’ or international political, financial or economic conditions, as in the judgment

of the Representatives is material and adverse and makes it impracticable to market the Offered Securities in the manner and on the terms

described in the Time of Sale Prospectus or the Prospectus or to enforce contracts for the sale of securities; (iv) in the judgment

of the Representatives there shall have occurred any Material Adverse Change; or (v) the Company shall have sustained a loss by

strike, fire, flood, earthquake, accident or other calamity of such character as in the judgment of the Representatives may interfere

materially with the conduct of the business and operations of the Company regardless of whether or not such loss shall have been insured.

Any termination pursuant to this Section 12 shall be without liability on the part of (a) the Company to any Underwriter, except

that the Company shall be obligated to reimburse the expenses of the Representatives and the Underwriters pursuant to Section 4

or Section 7 hereof or (b) any Underwriter to the Company; provided, however, that the provisions of Section 9

and Section 10 shall at all times be effective and shall survive such termination.

Section 13.             No

Advisory or Fiduciary Relationship; Research Analyst Independence. The Company acknowledges and agrees that (a) the purchase

and sale of the Offered Securities pursuant to this Agreement, including the determination of the offering price of the Offered Securities

and any related discounts and commissions, is an arm’s-length commercial transaction between the Company, on the one hand, and

the several Underwriters, on the other hand, and does not constitute a recommendation, investment advice, or solicitation of any actions

by the Underwriters, (b) in connection with the offering contemplated hereby and the process leading to such transaction, each Underwriter

is and has been acting solely as a principal and is not the agent or fiduciary of the Company, or its stockholders, creditors, employees

or any other party, (c) no Underwriter has assumed or will assume an advisory or fiduciary responsibility in favor of the Company

with respect to the offering contemplated hereby or the process leading thereto (irrespective of whether such Underwriter has advised

or is currently advising the Company on other matters) and no Underwriter has any obligation to the Company with respect to the offering

contemplated hereby except the obligations expressly set forth in this Agreement, (d) the Underwriters and their respective affiliates

may be engaged in a broad range of transactions that involve interests that differ from those of the Company, (e) the Underwriters

have not provided any legal, accounting, regulatory or tax advice with respect to the offering contemplated hereby, and the Company has

consulted its own legal, accounting, regulatory and tax advisors to the extent it deemed appropriate, and (f) none of the activities

of the Underwriters in connection with the transactions contemplated herein constitutes a recommendation, investment advice or solicitation

of any action by the Underwriters with respect to any entity or natural person.

The Company acknowledges

that the Underwriters’ research analysts and research departments are required to be independent from their respective investment

banking divisions and are subject to certain regulations and internal policies, and that such Underwriters’ research analysts may

hold views and make statements or investment recommendations and/or publish research reports with respect to the Company and/or the offering

that differ from the views of their respective investment banking divisions. The Company hereby waives and releases, to the fullest extent

permitted by law, any claims that the Company may have against the Underwriters with respect to any conflict of interest that may arise

from the fact that the views expressed by their independent research analysts and research departments may be different from or inconsistent

with the views or advice communicated to the Company by such Underwriters’ investment banking divisions. The Company acknowledges

that each of the Underwriters is a full service securities firm and as such from time to time, subject to applicable securities laws,

may effect transactions for its own account or the account of its customers and hold long or short positions in debt or equity securities

of the companies that may be the subject of the transactions contemplated by this Agreement.

Section 14.            Representations

and Indemnities to Survive Delivery. The respective indemnities, agreements, representations, warranties and other statements

of the Company, of its officers and of the several Underwriters set forth in or made pursuant to this Agreement will remain in full force

and effect, regardless of any investigation made by or on behalf of any Underwriter or the Company or any of its or their partners, officers

or directors or any controlling person, as the case may be, and, anything herein to the contrary notwithstanding, will survive delivery

of and payment for the Offered Securities sold hereunder and any termination of this Agreement.

Section 15.            Notices.

All communications hereunder shall be in writing and effective only upon receipt and if to the Underwriters shall be delivered, mailed

or sent to Leerink Partners LLC, 1301 Avenue of the Americas, 5th Floor, New York, New York 10019, Attention: Stuart R. Nayman; to Barclays

Capital Inc., 745 Seventh Avenue, New York, New York 10019, Attention: Syndicate Registration (Fax: (646) 834-8133), with a copy, in

the case of any notice pursuant to Section 9(c), to the Director of Litigation, Office of the General Counsel, Barclays Capital

Inc., 745 Seventh Avenue, New York, NY 10019; with a copy to Cooley LLP, 55 Hudson Yards, New York, New York 10001, Attention: Daniel

I. Goldberg and Eric Blanchard; and if to the Company shall be delivered, mailed or sent to Altimmune, Inc., 910 Clopper Road, Suite 201S,

Gaithersburg, Maryland 20878, Attention: Gregory Weaver with a copy to Goodwin Procter LLP, 100 Northern Avenue, Boston, Massachusetts

02210, Attention: Joseph C. Theis, Jr. and Justin Anslow. Any party hereto may change the address for receipt of communications

by giving written notice to the others.

Section 16.            Successors.

This Agreement will inure to the benefit of and be binding upon the parties hereto, including any substitute Underwriters pursuant to

Section 11 hereof, and to the benefit of the affiliates, directors, officers, employees, agents and controlling persons referred

to in Section 9 and Section 10, and in each case their respective successors, and no other person will have any right or obligation

hereunder. The term “successors” shall not include any purchaser of the Offered Securities as such from any of the

Underwriters merely by reason of such purchase.

Section 17.            Partial

Unenforceability. The invalidity or unenforceability of any section, paragraph or provision of this Agreement shall not affect the

validity or enforceability of any other section, paragraph or provision hereof. If any section, paragraph or provision of this Agreement

is for any reason determined to be invalid or unenforceable, there shall be deemed to be made such minor changes (and only such minor

changes) as are necessary to make it valid and enforceable.

Section 18.            Recognition

of the U.S. Special Resolution Regimes.

(a)            In

the event that any Underwriter that is a Covered Entity becomes subject to a proceeding under a U.S. Special Resolution Regime, the transfer

from such Underwriter of this Agreement, and any interest and obligation in or under this Agreement, will be effective to the same extent

as the transfer would be effective under the U.S. Special Resolution Regime if this Agreement, and any such interest and obligation,

were governed by the laws of the United States or a state of the United States.

(b)            In

the event that any Underwriter that is a Covered Entity or a BHC Act Affiliate of such Underwriter becomes subject to a proceeding under

a U.S. Special Resolution Regime, Default Rights under this Agreement that may be exercised against such Underwriter are permitted to

be exercised to no greater extent than such Default Rights could be exercised under the U.S. Special Resolution Regime if this Agreement

were governed by the laws of the United States or a state of the United States.

For purposes of this Agreement, (A) “BHC

Act Affiliate” has the meaning assigned to the term “affiliate” in, and shall be interpreted in accordance with,

12 U.S.C. § 1841(k); (B) “Covered Entity” means any of the following: (i) a “covered entity”

as that term is defined in, and interpreted in accordance with, 12 C.F.R. § 252.82(b); (ii) a “covered bank” as

that term is defined in, and interpreted in accordance with, 12 C.F.R. § 47.3(b); or (iii) a “covered FSI” as that

term is defined in, and interpreted in accordance with, 12 C.F.R. § 382.2(b); (C) “Default Right” has the

meaning assigned to that term in, and shall be interpreted in accordance with, 12 C.F.R. §§ 252.81, 47.2 or 382.1, as applicable;

and (D) “U.S. Special Resolution Regime” means each of (i) the Federal Deposit Insurance Act and the regulations

promulgated thereunder and (ii) Title II of the Dodd-Frank Wall Street Reform and Consumer Protection Act and the regulations promulgated

thereunder.

Section 19.            Governing

Law Provisions. This Agreement shall be governed by and construed in accordance with the internal laws of the State of New

York applicable to agreements made and to be performed in such state. Any legal suit, action or proceeding arising out of or based upon

this Agreement or the transactions contemplated hereby (“Related Proceedings”) may be instituted in the federal courts

of the United States of America located in the Borough of Manhattan in the City of New York or the courts of the State of New York in

each case located in the Borough of Manhattan in the City of New York (collectively, the “Specified Courts”), and

each party irrevocably submits to the exclusive jurisdiction (except for proceedings instituted in regard to the enforcement of a judgment

of any such court (a “Related Judgment”), as to which such jurisdiction is non-exclusive) of such courts in any such

suit, action or proceeding. Service of any process, summons, notice or document by mail to such party’s address set forth above

shall be effective service of process for any suit, action or other proceeding brought in any such court. The parties irrevocably and

unconditionally waive any objection to the laying of venue of any suit, action or other proceeding in the Specified Courts and irrevocably

and unconditionally waive and agree not to plead or claim in any such court that any such suit, action or other proceeding brought in

any such court has been brought in an inconvenient forum. The Company and the Underwriters hereby irrevocably waive, to the fullest extent

permitted by applicable law, any and all right to trial by jury in any legal proceeding arising out of or relating to this Agreement

or the transactions contemplated hereby.

Section 20.            General

Provisions. This Agreement constitutes the entire agreement of the parties to this Agreement and supersedes all prior written or

oral and all contemporaneous oral agreements, understandings and negotiations with respect to the subject matter hereof. This Agreement

may be executed in any number of counterparts, each of which shall be deemed to be an original, but all such counterparts shall together

constitute one and the same agreement. Counterparts may be delivered via facsimile, electronic mail (including any electronic signature

covered by the U.S. federal ESIGN Act of 2000, Uniform Electronic Transactions Act, the Electronic Signatures and Records Act or other

applicable law, e.g., www.docusign.com) or other transmission method and any counterpart so delivered shall be deemed to have been duly

and validly delivered and be valid and effective for all purposes. This Agreement may not be amended or modified unless in writing by

all of the parties hereto, and no condition herein (express or implied) may be waived unless waived in writing by each party whom the

condition is meant to benefit. The section headings herein are for the convenience of the parties only and shall not affect the construction

or interpretation of this Agreement.

Each of the parties hereto acknowledges that it

is a sophisticated business person who was adequately represented by counsel during negotiations regarding the provisions hereof, including,

without limitation, the indemnification provisions of Section 9 and the contribution provisions of Section 10, and is fully

informed regarding said provisions. Each of the parties hereto further acknowledges that the provisions of Section 9 and Section 10

hereof fairly allocate the risks in light of the ability of the parties to investigate the Company, its affairs and its business in order

to assure that adequate disclosure has been made in the Registration Statements, any preliminary prospectus, the Time of Sale Prospectus,

each free writing prospectus and the Prospectus (and any amendments and supplements to the foregoing), as contemplated by the Securities

Act and the Exchange Act.

[Signature Pages Follow]

Very truly yours,

ALTIMMUNE, INC.

By:

/s/

Gregory Weaver

Name: Gregory Weaver

Title:   Chief

Financial Officer

[Signature page to the altimmune, inc. Underwriting

agreement]

Restricted - External

Accepted as of the date hereof

Leerink Partners LLC

Acting severally on behalf of itself and the

several Underwriters named in Schedule A

hereto.

By:

Leerink

Partners LLC

By:

/s/ Jon Civitarese

Name: Jon Civitarese

Title:   Senior Managing Director

[Signature Page To The Altimmune, Inc. Underwriting Agreement]

Accepted as of the date hereof

BARCLAYS CAPITAL INC.

Acting severally on behalf of itself and the

several Underwriters named in Schedule A

hereto.

By:

BARCLAYS CAPITAL INC.

By:

/s/ Dan Cocks

Name: Dan Cocks

Title:   Managing Director

[Signature Page To The Altimmune, Inc. Underwriting

Agreement]

Schedule A

Underwriter

Number of

To Be

Purchased

Number of Pre-

Funded

Warrants To Be

Purchased

Number of

Common

Warrants To Be

Purchased

Leerink Partners LLC

34,052,500

5,697,500

39,750,000

Barclays Capital Inc.

20,560,000

3,440,000

24,000,000

Titan Partners Group LLC, a division of American Capital Partners,

LLC

9,637,500

1,612,500

11,250,000

Total:

64,250,000

10,750,000

75,000,000

Schedule B

Free Writing Prospectuses Included in the

Time of Sale Prospectus

None

Schedule C

Time of Sale Information

1. The Company is selling 64,250,000 Shares and 64,250,000 accompanying Common

Warrants.

2. The Company is selling 10,750,000 Pre-Funded Warrants and 10,750,000 accompanying

Common Warrants.

3. The offering price shall be $3.00 per Share and accompanying Common Warrant

and $2.999 per Pre-Funded Warrant and accompanying Common Warrant.

4. The exercise price per underlying share of Common Stock exercisable pursuant

to the Common Warrants is $3.00.

Exhibit A

Form of Lock-up Agreement

April , 2026

Leerink Partners LLC

Barclays Capital Inc.

As Representatives of the Several Underwriters

c/o Leerink Partners LLC

53 State Street, 40th Floor

Boston, Massachusetts 02109

c/o Barclays Capital Inc.

745 Seventh Avenue

New York, New York 10019

RE: Altimmune, Inc. (the “Company”)

Ladies and Gentlemen:

The undersigned is a holder of shares of common stock, par value $0.0001

per share, of the Company (“Shares”) or of Related Securities. The Company proposes to conduct an offering (the “Offering”)

of Shares and Related Securities for which Leerink Partners LLC and Barclays Capital Inc. will act as the representatives (the “Representatives”)

of the underwriters (the “Underwriters”). The undersigned recognizes that the Offering will benefit each of the Company

and the undersigned. The undersigned acknowledges that the Underwriters are relying on the representations and agreements of the undersigned

contained in this letter agreement in conducting the Offering and, at a subsequent date, in entering into an underwriting agreement (the

“Underwriting Agreement”) and other underwriting arrangements with the Company with respect to the Offering.

Annex A sets forth definitions for capitalized terms used in

this letter agreement that are not defined in the body of this letter agreement. Those definitions are a part of this letter agreement.

In consideration of the foregoing, and for other good and valuable

consideration, the receipt and sufficiency of which are hereby acknowledged, the undersigned hereby agrees that, during the Lock-up Period,

the undersigned will not (and will cause any Family Member not to), without the prior written consent of the Representatives, which may

withhold their consent in their sole discretion:

· Sell

or Offer to Sell any Shares or Related Securities currently or hereafter owned either of

record or beneficially (as defined in Rule 13d-3 under the Exchange Act) by the undersigned

or such Family Member,

· enter

into any Swap,

· make

any demand for, or exercise any right with respect to, the registration under the Securities

Act of the offer and sale of any Shares or Related Securities, or cause to be filed a registration

statement, prospectus or prospectus supplement (or an amendment or supplement thereto) with

respect to any such registration, or

· publicly

announce any intention to do any of the foregoing.

The foregoing will not apply to the registration of the offer and

sale of the Shares and the Related Securities, and the sale of the Shares and the Related Securities to the Underwriters, in each case

as contemplated by the Underwriting Agreement. In addition, the foregoing restrictions shall not apply to:

(i) transactions relating to Shares and Related

Securities acquired in the Offering or in open market transactions after the completion of the Offering;

(ii) transfers of Shares or Related Securities

by gift, including, without limitation, to a charitable organization, or by will or intestate succession to the legal representative,

heir, beneficiary or any Family Member of the undersigned, or to a trust whose beneficiaries consist exclusively of one or more of the

undersigned and/or a Family Member;

(iii) transfers or dispositions of Shares

or Related Securities to a Family Member, a trust formed for the direct or indirect benefit of the undersigned or an Immediate Family

Member or any corporation, partnership, limited liability company or other entity all of the beneficial ownership interests of which,

in each case, are held by the undersigned or any Family Member;

(iv) transfers of Shares or Related Securities

by operation of law pursuant to a qualified domestic order or other court order or in connection with a divorce settlement;

(v) if the undersigned is a corporation,

partnership, limited liability company, trust or other business entity, transfers or distributions of Shares or Related Securities to

(x) another corporation, partnership, limited liability company, trust or other business entity that is a direct or indirect affiliate

(as defined in Rule 405 promulgated under the Securities Act) of the undersigned, (y) any investment fund or other entity controlling,

controlled by, managing or managed by or under common control with the undersigned or affiliates of the undersigned, or (z) limited

partners, general partners, members, managers, managing members, directors, officers, employees, stockholders or other equity holders

of the undersigned or of the entities described in the preceding clauses (x) and (y);

(vi) transfers or dispositions of Shares

as (x) forfeitures to satisfy tax withholding and remittance obligations of the undersigned in connection with the vesting or exercise

of equity awards granted pursuant to the Company’s equity incentive plans, (y) forfeitures pursuant to a net exercise or cashless

exercise by the undersigned of outstanding equity awards pursuant to the Company’s equity incentive plans or (z) open market

sales of Shares to the extent necessary to satisfy tax and fee obligations of the undersigned in connection with the exercise of stock

options granted pursuant to the Company’s equity incentive plans expiring during the Lock-up Period;

(vii) transfers of Shares or Related Securities

pursuant to a change of control of the Company (meaning the consummation of any bona fide third party tender offer, merger, consolidation

or other similar transaction made to all holders of Shares the result of which is that any “person” (as defined in Section 13(d)(3) of

the Exchange Act), or group of persons, becomes the beneficial owner (as defined in Rules 13d-3 and 13d-5 of the Exchange Act) of

more than 50% of the voting capital stock of the Company) after the Offering that has been approved by the independent members of the

Company’s board of directors, provided, that in the event that such change of control is not completed, the Shares or Related

Securities owned by the undersigned shall remain subject to the restrictions herein;

(viii) transfers of Shares or Related Securities

arising as a result of the termination of employment of the undersigned to the Company pursuant to agreements under which the Company

has the option to repurchase such Shares or Related Securities or a right of first refusal with respect to transfers of such Shares or

Related Securities; or

(ix) transfers or dispositions of Shares

under a trading plan pursuant to Rule 10b5-1 under the Exchange Act for the transfer or disposition of Shares that is existing as

of the date hereof provided that to the extent a public announcement or filing under the Exchange Act, if any, is required of

or voluntarily made by or on behalf of the undersigned such transfer, such announcement or filing shall include a statement to the effect

that such dispositions were made pursuant to such plan.

Notwithstanding the foregoing, it shall be a condition to such transfer

that:

· in

any such case as provided in clauses (ii) through (v), each transferee or distributee

executes and delivers to the Representatives an agreement in form and substance satisfactory

to the Representatives stating that such transferee or distributee is receiving and holding

such Shares and/or Related Securities subject to the provisions of this letter agreement

and agrees not to Sell or Offer to Sell such Shares and/or Related Securities, engage in

any Swap or engage in any other activities restricted under this letter agreement except

in accordance with this letter agreement (as if such transferee or distribute had been an

original signatory hereto), and

· in

any such case as provided in clauses (i) through (iii), (v) and (viii), prior to

the expiration of the Lock-up Period, no public disclosure or filing under the Exchange Act

by any party to the transfer (donor, donee, transferor or transferee) shall be required,

or made voluntarily, reporting a reduction in beneficial ownership of Shares in connection

with such transfer (other than, in connection with a repurchase of Shares or Related Securities

by the Company pursuant to clause (viii), a Form 4 or Form 5 required to be filed

under the Exchange Act if the undersigned is subject to Section 16 reporting with respect

to the Company under the Exchange Act, provided, however, that if such Form 4

or Form 5 is filed during the Lock-up Period, such Form 4 or Form 5 shall

indicate by footnote disclosure or otherwise that such Form 4 or Form 5 relates

to a repurchase of Shares or Related Securities by the Company in connection with the termination

of the undersigned’s employment with the Company, and that any Shares or Related Securities

subject to this letter agreement that continue to be held by the undersigned remain subject

to the terms of this letter agreement), and

· in

any such case as provided in clauses (ii), (iii) and (v), each such transfer does not

involve a disposition for value, and

· in

any such case as provided in clauses (iv) and (vi) and, prior to the expiration

of the Lock-up Period, (1) that if a Form 4 or Form 5 is required to be filed

during the Lock-up Period, such Form 4 or Form 5 shall clearly indicate in the

footnotes thereto that (A) the filing relates to the circumstances described in such

clause and (B) no securities were sold by the undersigned, except for as allowed by

clause (vi)(z), and (2) the undersigned does not otherwise voluntarily effect any other

public filing or report regarding such transfers during the Lock-up Period.

Furthermore, notwithstanding the restrictions imposed by this letter

agreement, the undersigned may (i) exercise an option to purchase Shares granted under any equity incentive plan or stock purchase

plan of the Company, provided that the Shares issued upon such exercise shall continue to be subject to the restrictions on transfer

set forth in this letter agreement and (ii) establish a trading plan pursuant to Rule 10b5-1 under the Exchange Act (a “10b5-1

Plan”) for the transfer of Shares, provided that (x) such 10b5-1 Plan shall not provide for or permit any transfers,

sales or other dispositions of Shares during the Lock-up Period and (y) to the extent a public announcement or filing under the

Exchange Act, if any, is required of or voluntarily made by or on behalf of the undersigned or the Company regarding the establishment

of such plan, such announcement or filing shall include a statement to the effect that no transfer of Shares may be made under such plan

during the Lock-up Period. In addition, the undersigned agrees that, without the prior written consent of the Representatives on behalf

of the Underwriters, it will not, during the Lock-up Period, make any demand for or exercise any right with respect to, the registration

of any Shares or Related Securities. The undersigned also agrees and consents to the entry of stop transfer instructions with the Company’s

transfer agent and registrar against the transfer of Shares or Related Securities held by the undersigned and the undersigned’s

Family Members, if any, except in compliance with the foregoing restrictions. With respect to the Offering only, the undersigned waives

any registration rights relating to registration under the Securities Act of the offer and sale of any Shares and/or any Related Securities

owned either of record or beneficially by the undersigned, including any rights to receive notice of the Offering.

The undersigned confirms that the undersigned has not, and has no

knowledge that any Family Member has, directly or indirectly, taken any action designed to or that might reasonably be expected to cause

or result in the stabilization or manipulation of the price of any security of the Company to facilitate the sale of the Shares. The

undersigned will not, and will cause any Family Member not to take, directly or indirectly, any such action.

The undersigned understands that the Company and the Underwriters

are relying upon this letter agreement in proceeding toward consummation of the Offering. The undersigned further understands that this

letter agreement is irrevocable and shall be binding upon the undersigned’s heirs, legal representatives, successors and assigns.

The undersigned acknowledges and agrees that, although the Underwriters

may provide certain Regulation Best Interest and Form CRS disclosures or other related documentation to the undersigned in connection

with the Offering, the Underwriters have not provided any recommendation or investment advice nor have the Underwriters solicited any

action from the undersigned with respect to the Offering and the undersigned has consulted their own legal, accounting, financial, regulatory

and tax advisors to the extent deemed appropriate.

Whether or not the Offering occurs as currently contemplated or at

all depends on a number of factors, including market conditions. The Offering will only be made pursuant to the Underwriting Agreement,

the terms of which are subject to negotiation between the Company and the Underwriters.

If (i) prior to the execution of the Underwriting Agreement,

the Company, on the one hand, or the Representatives, on the other hand, notify the other in writing that they do not intend to proceed

with the Offering, (ii) the Company files an application to withdraw the registration statement related to the Offering, (iii) the

Underwriting Agreement is not executed on or before May 15, 2026, or (iv) the Underwriting Agreement (other than the provisions

thereof that survive termination) terminates or is terminated prior to the closing date of the Offering, then in each case, this letter

agreement shall automatically, and without any action on the part of any other party, terminate and be of no further force and effect,

and the undersigned shall automatically be released from the obligations under this letter agreement.

The undersigned hereby represents and warrants that the undersigned

has full power, capacity and authority to enter into this letter agreement. This letter agreement is irrevocable and will be binding

on the undersigned and the successors, heirs, personal representatives and assigns of the undersigned.

This letter agreement shall be governed by, and construed in accordance

with, the laws of the State of New York.

[Signature Page Follows]

Signature

Printed

Name of Person Signing

(Indicate

capacity of person signing if

signing as custodian or trustee, or on behalf

of an entity)

[Signature Page to Lock-up Agreement]

Annex A

Certain Defined Terms

Used in Lock-up Agreement

For purposes of the letter agreement to which

this Annex A is attached and of which it is made a part:

· “Call

Equivalent Position” shall have the meaning set forth in Rule 16a-1(b) under

the Exchange Act.

· “Exchange

Act” shall mean the Securities Exchange Act of 1934, as amended.

· “Family

Member” shall mean the spouse of the undersigned, an immediate family member of

the undersigned or an immediate family member of the undersigned’s spouse, in each

case living in the undersigned’s household or whose principal residence is the undersigned’s

household (regardless of whether such spouse or family member may at the time be living elsewhere

due to educational activities, health care treatment, military service, temporary internship

or employment or otherwise). “Immediate family member” as used above shall

have the meaning set forth in Rule 16a-1(e) under the Exchange Act.

· “Lock-up

Period” shall mean the period beginning on the date hereof and continuing through

the close of trading on the date that is 90 days after the date of the Prospectus (as defined

in the Underwriting Agreement).

· “Put

Equivalent Position” shall have the meaning set forth in Rule 16a-1(h) under

the Exchange Act.

· “Related

Securities” shall mean any options or warrants or other rights to acquire Shares

or any securities exchangeable or exercisable for or convertible into Shares, or to acquire

other securities or rights ultimately exchangeable or exercisable for or convertible into

Shares.

· “Securities

Act” shall mean the Securities Act of 1933, as amended.

· “Sell

or Offer to Sell” shall mean to:

– sell, offer to sell, contract to sell or lend,

– effect any short sale or establish or increase a Put Equivalent

Position or liquidate or decrease any Call Equivalent Position,

– pledge, hypothecate or grant any security interest in, or

– in any other way transfer or dispose of,

in each case whether effected directly

or indirectly.

· “Swap”

shall mean any swap, hedge or similar arrangement or agreement that transfers, in whole or

in part, the economic risk of ownership of Shares or Related Securities, regardless of whether

any such transaction is to be settled in securities, in cash or otherwise.

Capitalized terms not defined in this Annex

A shall have the meanings given to them in the body of this lock-up agreement.

Exhibit B

Directors and Officers

Signing Lock-up Agreement

Directors:

· Mitchel

Sayare

· Jerome

Durso

· John

Gill

· Philip

Hodges

· Diane

K. Jorkasky

· Teri

Lawver

· Wayne

Pisano

· Klaus

O. Schafer

· Catherine

Sohn

Executive Officers:

· Gregory

Weaver

· M.

Scot Roberts

· Linda

Richardson

· Christophe

Arbet-Engels

EX-4.1 — EXHIBIT 4.1

EX-4.1

Filename: tm2612493d2_ex4-1.htm · Sequence: 3

Exhibit 4.1

The Company has filed a registration statement (including a prospectus)

with the SEC for the offering to which this communication relates. Before you invest, you should read the prospectus in that registration

statement and other documents the issuer has filed with the SEC for more complete information about the issuer and this offering. You

may get these documents for free by visiting EDGAR on the SEC Web site at www.sec.gov.

FORM OF WARRANT TO PURCHASE COMMON STOCK

OR PRE-FUNDED WARRANTS

ALTIMMUNE, INC.

Number of Shares: [ ]

(subject to adjustment as provided herein)

Warrant

No.

Initial Exercise Date: As defined herein

Altimmune, Inc., a Delaware corporation (the

“Company”), hereby certifies that, for good and valuable consideration, the receipt and sufficiency of which are hereby

acknowledged, [ ] or its registered assigns (the “Holder”) is entitled, subject to the terms set forth below,

to purchase from the Company up to a total of [ ] shares of common stock, $0.0001 par value per share (the “Common Stock”),

of the Company (each such share, a “Warrant Share” and all such shares, the “Warrant Shares”), or

Pre-Funded Warrants as contemplated by Section 4(b), at an exercise price per share equal to $[___] (the “Exercise

Price”), in each case as adjusted from time to time as provided in Section 9, at any time and from time to time

on or after the date hereof (the “Initial Exercise Date”) and on or prior to 5:00 p.m. (New York City time) on

the Termination Date (as defined below)but not thereafter, subject to the following terms and conditions:

1. Definitions. For purposes of this Warrant

to Purchase Common Stock or Pre-Funded Warrants (including any Warrants to Purchase Common Stock or Pre-Funded Warrants issued in exchange,

transfer or replacement hereof, the “Warrant”), the following terms shall have the following meanings:

(a) “Affiliate”

means any Person directly or indirectly controlled by, controlling or under common control with, a Holder, but only for so long as such

control shall continue. For purposes of this definition, “control” (including, with correlative meanings, “controlled

by,” “controlling” and “under common control with”) means, with respect to a Person, possession, direct

or indirect, of (a) the power to direct or cause direction of the management and policies of such Person (whether through ownership

of securities or partnership or other ownership interests, by contract or otherwise), or (b) at least 50% of the voting securities

(whether directly or pursuant to any option, warrant or other similar arrangement) or other comparable equity interests.

(b) “Attribution

Parties” means, collectively, the following Persons and entities: (i) any direct or indirect Affiliates of the Holder,

(ii) any investment vehicle, including, any funds, feeder funds or managed accounts, currently, or from time to time after the date

hereof, directly or indirectly managed or advised by the Holder’s investment manager, (iii) any Person acting or who could

be deemed to be acting as a Group together with the Holder or any Attribution Parties and (iv) any other Persons whose beneficial

ownership of the Company’s Common Stock would or could be aggregated with the Holder’s and/or any other Attribution Parties

for purposes of Section 13(d) or Section 16 of the Exchange Act. For clarity, the purpose of the foregoing is to subject

collectively the Holder and all other Attribution Parties to the Maximum Percentage.

Shares” means authorized but unissued shares of Common Stock that are available for issuance by the Company (excluding any shares

that are issuable upon exercise, conversion or exchange of outstanding options, warrants or other securities or are reserved under any

equity plan maintained by the Company).

(d) “Closing

Sale Price” means, for any security as of any date, the last trade price for such security on the Principal Trading Market for

such security, as reported by Bloomberg Financial Markets, or, if such Principal Trading Market begins to operate on an extended hours

basis and does not designate the last trade price, then the last trade price of such security prior to 4:00 P.M., New York City time,

as reported by Bloomberg Financial Markets, or if the foregoing do not apply, the last trade price of such security in the over-the-counter

market on the electronic bulletin board for such security as reported by Bloomberg Financial Markets. If the Closing Sale Price cannot

be calculated for a security on a particular date on any of the foregoing bases, the Closing Sale Price of such security on such date

shall be the fair market value as mutually determined by the Company and the Holder. If the Company and the Holder are unable to agree

upon the fair market value of such security, then the board of directors of the Company shall use its good faith judgment to determine

the fair market value. The determination of the board of directors of the Company shall be binding upon all parties absent demonstrable

error. All such determinations shall be appropriately adjusted for any stock dividend, stock split, stock combination or other similar

transaction during the applicable calculation period.

(e) “Commission”

means the U.S. Securities and Exchange Commission.

(f) “Exchange

Act” means the U.S. Securities Exchange Act of 1934, as amended, and all of the rules and regulations promulgated thereunder.

(g) “Group”

shall have the meaning ascribed to it in Section 13(d) of the Exchange Act, and all related rules, regulations and jurisprudence.

(h) “Milestone

Event” means the Company publicly announcing a successful data readout of the Phase 3 trial of pemvidutide in metabolic dysfunction-associated

steatohepatitis (MASH).

(i) “Person”

means an individual, partnership, corporation, limited liability company, business trust, joint stock company, trust, incorporated or

unincorporated association, joint venture, government (or an agency or subdivision thereof) or any other entity or organization.

(j) “Principal

Trading Market” means the national securities exchange or other trading market on which the Common Stock is primarily listed

on and quoted for trading, which, as of the Initial Exercise Date, shall be the Nasdaq Global Select Market.

(k) “Registration

Statement” means the Company’s Registration Statement on Form S-3 (File No. 333-291329), as amended, initially

filed by the Company with the Commission on November 6, 2025 in the form which it became effective on December 5, 2025.

(l) “Securities

Act” means the U.S. Securities Act of 1933, as amended, and all of the rules and regulations promulgated thereunder.

(m) “Standard

Settlement Period” means the standard settlement period, expressed in a number of Trading Days, for the Principal Trading Market

with respect to the Common Stock that is in effect on the date of delivery of an applicable Exercise Notice, which as of the Initial Exercise

Date was “T+1.”

(n) “Termination

Date” means the earlier of (i) the fifth (5th) anniversary of the date hereof or (ii) forty-five (45) days after the

date the Milestone Event occurs, provided that, in each case, if such date falls on a day other than a Business Day or on a date on which

trading does not take place on the Principal Market (a “Holiday”), the Termination Date shall be the next day that

is not a Holiday.

(o) “Trading

Day” means any weekday on which the Principal Trading Market is normally open for trading.

(p) “Trading

Market” means any of the following markets or exchanges on which the Common Stock is listed or quoted for trading on the date

in question: the NYSE American, the Nasdaq Capital Market, the Nasdaq Global Market, the Nasdaq Global Select Market or the New York Stock

Exchange (or any successors to any of the foregoing).

(q) “Transfer

Agent” means Continental Stock Transfer & Trust Company, the Company’s transfer agent and registrar for the Common

Stock, and any successor appointed in such capacity.

(r) “VWAP”

means, for any date, the price determined by the first of the following clauses that applies: (a) if the Common Stock is then listed

or quoted on a Trading Market, the daily volume weighted average price of the Common Stock for such date (or the nearest preceding date)

on the Trading Market on which the Common Stock is then listed or quoted as reported by Bloomberg (based on a Trading Day from 9:30 a.m. (New

York City time) to 4:02 p.m. (New York City time)), (b) if OTCQB or OTCQX is not a Trading Market, the volume weighted average

price of the Common Stock for such date (or the nearest preceding date) on OTCQB or OTCQX as applicable, (c) if the Common Stock

is not then listed or quoted for trading on OTCQB or OTCQX and if prices for the Common Stock are then reported on The Pink Open Market

(or a similar organization or agency succeeding to its functions of reporting prices), the most recent bid price per share of the Common

Stock so reported, or (d) in all other cases, the fair market value of a share of Common Stock as determined by an independent appraiser

selected in good faith by the holders of a majority in interest of the Warrants then outstanding and reasonably acceptable to the Company,

the fees and expenses of which shall be paid by the Company.

2. Issuance of Securities; Registration of

Warrants. The Warrant, as initially issued by the Company, is offered and sold pursuant to the Registration Statement. As of the Initial

Exercise Date, the Warrant Shares are issuable under the Registration Statement. Accordingly, the Warrant and, assuming issuance pursuant

to the Registration Statement or an exchange meeting the requirements of Section 3(a)(9) of the Securities Act as in effect

on the Initial Exercise Date, the Warrant Shares, are not “restricted securities” under Rule 144 promulgated under the

Securities Act. The Company shall register ownership of this Warrant, upon records to be maintained by the Company for that purpose (the

“Warrant Register”), in the name of the record Holder (which shall include the initial Holder or, as the case may be,

any assignee to which this Warrant is permissibly assigned hereunder) from time to time. The Company may deem and treat the registered

Holder of this Warrant as the absolute owner hereof for the purpose of any exercise hereof or any distribution to the Holder, and for

all other purposes, absent actual notice to the contrary.

3. Registration of Transfers. Subject to

compliance with all applicable securities laws, the Company shall, or will cause its Transfer Agent to, register the transfer of all or

any portion of this Warrant in the Warrant Register, together with a written assignment of this Warrant substantially in the form attached

hereto as Schedule 2 duly executed by the Holder, and payment for all applicable transfer taxes (if any). Upon any such registration

or transfer, a new warrant in substantially the form of this Warrant (any such new warrant, a “New Warrant”) evidencing

the portion of this Warrant so transferred shall be issued to the transferee, and a New Warrant evidencing the remaining portion of this

Warrant not so transferred, if any, shall be issued to the transferring Holder. The acceptance of the New Warrant by the transferee thereof

shall be deemed the acceptance by such transferee of all of the rights and obligations in respect of the New Warrant that the Holder has

in respect of this Warrant. The Company shall, or will cause its Transfer Agent to, prepare, issue and deliver at the Company’s

own expense any New Warrant under this Section 3. Until due presentment for registration of transfer, the Company may treat

the registered Holder hereof as the owner and holder for all purposes, and the Company shall not be affected by any notice to the contrary.

4. Exercise of Warrants.

(a) All or any part

of this Warrant shall be exercisable by the registered Holder in any manner permitted by this Warrant (including Section 11)

at any time and from time to time on or after the Initial Exercise Date and on or before the Termination Date.

(b) The Holder may exercise

this Warrant by delivering to the Company (i) an exercise notice, in the form attached as Schedule 1 hereto (the “Exercise

Notice”), completed and duly signed by an authorized officer of the Holder, of the Holder’s election to exercise this

Warrant for, at the Holder’s sole discretion, either (A) Warrant Shares or (B) Pre-Funded Warrants to purchase a number

of shares of Common Stock equal to the number of Warrant Shares as to which this Warrant would otherwise be exercised in substantially

the same form of Pre-Funded Warrant attached hereto as Schedule 3 (“Pre-Funded Warrants”) with an exercise price

of $0.0001 per share of Common Stock and (ii) payment of the Exercise Price for the number of Warrant Shares as to which this Warrant

is being exercised (which may take the form of a “cashless exercise” under certain limited circumstances pursuant to the terms

of Section 10 below), or, if this Warrant is being exercised for Pre-Funded Warrants, the Exercise Price, less $0.0001, multiplied

by the number of Warrant Shares as to which this Warrant would otherwise be exercised, and the date on which the last of such items is

delivered to the Company (as determined in accordance with the notice provisions hereof) is an “Exercise Date.” The

Holder shall not be required to deliver the original Warrant in order to effect an exercise hereunder. Execution and delivery of the Exercise

Notice shall have the same effect as cancellation of the original Warrant and issuance of a New Warrant evidencing the right to purchase

the remaining number of Warrant Shares or Pre-Funded Warrants, if any. The Holder and the Company shall maintain records showing

the number of Warrant Shares and/or Pre-Funded Warrants purchased and the dates of such purchases. The Company shall deliver any objection

to any Exercise Notice within one (1) Trading Day of receipt of such notice. The Holder and any assignee, by acceptance of this

Warrant, acknowledge and agree that, by reason of the provisions of this paragraph, following the purchase of a portion of the Warrant

Shares and Pre-Funded Warrants hereunder, the number of Warrant Shares and Pre-Funded Warrants available for purchase hereunder at any

given time may be less than the amount stated on the face hereof.

5. Delivery of Warrant Shares.

(a) If this Warrant

is being exercised for Warrant Shares, upon exercise of this Warrant, the Company shall, or shall cause the Transfer Agent to, promptly

(but in no event later than the number of Trading Days comprising the Standard Settlement Period following the Exercise Date), upon the

request of the Holder, credit such aggregate number of shares of Common Stock specified by the Holder in the Exercise Notice and to which

the Holder is entitled pursuant to such exercise (the “Exercise Shares”) to (i) the Holder’s or its designee’s

balance account with The Depository Trust Company (“DTC”) through its Deposit Withdrawal At Custodian system or (ii) in

book-entry form via a direct registration system (“DRS”) maintained by or on behalf of the Transfer Agent, in each

case, so long as either (A) there is an effective registration statement permitting the issuance of the Warrant Shares to or the

resale of such Warrant Shares by the Holder, or (B) the Exercise Shares are eligible for resale by the Holder without volume or manner-of-sale

restrictions pursuant to Rule 144 promulgated under the Securities Act. If (A) and (B) above are not true, the Company

shall cause the Transfer Agent to either (i) record the Exercise Shares in the name of the Holder or its designee on the certificates

reflecting the Exercise Shares with an appropriate legend regarding restriction on transferability, which shall be issued and dispatched

by overnight courier to the address as specified in the Exercise Notice, and on the Company’s share register or (ii) issue

such Exercise Shares in the name of the Holder or its designee in restricted book-entry form in the Company’s share register. If

this Warrant is being exercised for Pre-Funded Warrants, the Company shall issue and dispatch by overnight courier to the address specified

in the Exercise Notice, Pre-Funded Warrants to purchase a number of shares of Common Stock equal to the number of Warrant Shares with

respect to which this Warrant would otherwise be exercised. The Holder, or any Person so designated by the Holder to receive Warrant Shares

or Pre-Funded Warrants, shall be deemed to have become the holder of record of such Warrant Shares or Pre-Funded Warrants as of the Exercise

Date, irrespective of the date such Warrant Shares or Pre-Funded Warrants are credited to the Holder’s DTC account, the date of

the book entry positions or the date of delivery of the certificates evidencing such Exercise Shares or Pre-Funded Warrants, as the case

may be.

(b) In addition to any

other rights available to the Holder, if this Warrant is being exercised for Warrant Shares and if the Company fails to deliver, or cause

the Transfer Agent to deliver, to the Holder or its designee Exercise Shares in the manner required pursuant to Section 5(a) within

the Standard Settlement Period following the Exercise Date (other than a failure caused by incorrect or incomplete information provided

by Holder to the Company) and the Holder or the Holder’s broker on its behalf purchases (in an open market transaction or otherwise)

shares of Common Stock to deliver in satisfaction of a sale by the Holder of the Warrant Shares which the Holder anticipated receiving

upon such exercise (a “Buy-In”) but did not receive within the Standard Settlement Period, then the Company shall,

within two (2) Trading Days after the Holder’s request and in the Holder’s sole discretion, promptly honor its obligation

to deliver to the Holder or its designee the Exercise Shares pursuant to Section 5(a) and pay cash to the Holder in an

amount equal to the excess (if any) of the Holder’s total purchase price (including brokerage commissions, if any) for the shares

of Common Stock so purchased in the Buy-In, less the product of (A) the number of shares of Common Stock purchased in the Buy-In,

times (B) the Closing Sale Price of a share of Common Stock on the Exercise Date. The Holder shall provide the Company with written

notice promptly after the occurrence of a Buy-In, indicating the amounts payable to the Holder in respect of the Buy-In together with

the applicable confirmations and other evidence reasonably requested by the Company. For the avoidance of doubt, the cash payment contemplated

by this Section 5(b) constitutes a damages remedy for the Company's failure to timely deliver Exercise Shares and does

not constitute a cash settlement of this Warrant or any portion thereof; the Company's primary obligation to deliver Exercise Shares upon

exercise of this Warrant remains absolute and unconditional in accordance with Section 5(c); and no payment made pursuant

to this Section 5(b) shall reduce, extinguish or otherwise affect the number of Warrant Shares issuable upon any future

exercise of this Warrant.

by law and subject to Section 5(b), the Company’s obligations to issue and deliver Warrant Shares or Pre-Funded Warrants,

as the case may be, in accordance with and subject to the terms hereof (including the limitations set forth in Section 11

below) are absolute and unconditional, irrespective of any action or inaction by the Holder to enforce the same, any waiver or consent

with respect to any provision hereof, the recovery of any judgment against any Person or any action to enforce the same, or any setoff,

counterclaim, recoupment, limitation or termination, or any breach or alleged breach by the Holder or any other Person of any obligation

to the Company or any violation or alleged violation of law by the Holder or any other Person, and irrespective of any other circumstance

that might otherwise limit such obligation of the Company to the Holder in connection with the issuance of Warrant Shares or Pre-Funded

Warrants. Subject to Section 5(b), nothing herein shall limit the Holder’s right to pursue any other remedies available

to it hereunder, at law or in equity including, without limitation, a decree of specific performance and/or injunctive relief with respect

to the Company’s failure to timely deliver Exercise Shares; provided, however, that the Holder shall not be entitled to both (i) require

the Company to reinstate the portion of the Warrant and equivalent number of Warrant Shares or Pre-Funded Warrants for which such exercise

was not timely honored and (ii) receive the number of shares of Common Stock that would have been issued if the Company had timely

complied with its delivery requirements under Section 5(a).

6. Charges, Taxes and Expenses. Issuance

and delivery of Exercise Shares or Pre-Funded Warrants shall be made without charge to the Holder for any issue or transfer tax, transfer

agent fee or other incidental tax or expense (excluding any applicable stamp duties) in respect of the issuance of such shares, all of

which taxes and expenses shall be paid by the Company; provided, however, that the Company shall not be required to pay

any tax that may be payable in respect of any transfer involved in the registration of any Exercise Shares or Pre-Funded Warrants or the

Warrants in a name other than that of the Holder or an Affiliate thereof. The Holder shall be responsible for all other tax liability

that may arise as a result of holding or transferring this Warrant or receiving Exercise Shares or Pre-Funded Warrants upon exercise hereof.

7. Replacement of Warrant. If this Warrant

is mutilated, lost, stolen or destroyed, the Company shall issue or cause to be issued in exchange and substitution for and upon cancellation

hereof, or in lieu of and substitution for this Warrant, a New Warrant, but only upon receipt of evidence reasonably satisfactory to the

Company of such loss, theft or destruction (in such case) and, in each case, a customary and reasonable contractual indemnity, if requested

by the Company. If a New Warrant is requested as a result of a mutilation of this Warrant, then the Holder shall deliver such mutilated

Warrant to the Company as a condition precedent to the Company’s obligation to issue the New Warrant.

8. Reservation of Warrant Shares.

(a) The Company covenants

that it will, at all times while this Warrant is outstanding, reserve and keep available out of the aggregate of its authorized but unissued

and otherwise unreserved Common Stock, solely for the purpose of enabling it to issue Warrant Shares upon exercise of this Warrant as

herein provided (or upon the exercise of Pre-Funded Warrants issued as contemplated hereby), the number of Warrant Shares that are initially

issuable and deliverable upon the exercise of this entire Warrant, free from preemptive rights or any other contingent purchase rights

of persons other than the Holder (taking into account the adjustments and restrictions of Section 9). The Company covenants that

all Warrant Shares so issuable and deliverable shall, upon delivery of this Warrant and the issuance and the payment of the applicable

Exercise Price in accordance with the terms hereof (and the terms of the Pre-Funded Warrants, if applicable), be duly and validly authorized,

issued and fully paid and non-assessable. The Company will take all such action as may be reasonably necessary to assure that such shares

of Common Stock may be issued as provided herein without violation of any applicable law or regulation, or of any requirements of any

securities exchange or automated quotation system upon which the Common Stock may be listed. The Company further covenants that it will

not, without the prior written consent of the Holder, take any actions to increase the par value of the Common Stock at any time while

this Warrant is outstanding.

9. Certain Adjustments. The Exercise Price

and number of Warrant Shares issuable upon exercise of this Warrant (the “Number of Warrant Shares”) are subject to

adjustment from time to time as set forth in this Section 9.

(a) Stock Dividends

and Splits. If the Company, at any time while this Warrant is outstanding, (i) pays a stock dividend on its Common Stock or otherwise

makes a distribution on any class of capital stock issued and outstanding on the Initial Exercise Date and in accordance with the terms

of such stock on the Initial Exercise Date or as amended, that is payable in shares of Common Stock, (ii) subdivides its outstanding

shares of Common Stock into a larger number of shares of Common Stock, (iii) combines its outstanding shares of Common Stock into

a smaller number of shares of Common Stock or (iv) issues by reclassification of shares of capital stock any additional shares of

Common Stock of the Company, then in each such case the Number of Warrant Shares shall be multiplied by a fraction, the numerator of which

shall be the number of shares of Common Stock outstanding immediately after such event and the denominator of which shall be the number

of shares of Common Stock outstanding immediately before such event. Any adjustment made pursuant to clause (i) of this paragraph

shall become effective immediately after the record date for the determination of stockholders entitled to receive such dividend or distribution,

provided, however, that if such record date shall have been fixed and such dividend is not fully paid on the date fixed therefor, the

Number of Warrant Shares shall be recomputed accordingly as of the close of business on such record date and thereafter the Number of

Warrant Shares shall be adjusted pursuant to this paragraph as of the time of actual payment of such dividends. Any adjustment pursuant

to clause (ii), (iii) or (iv) of this paragraph shall become effective immediately after the effective date of such subdivision,

combination or issuance.

(b) Pro Rata Distributions.

If, at any time while this Warrant is outstanding, the Company shall declare or make any dividend or other pro rata distribution of its

assets (or rights to acquire its assets) to holders of shares of Common Stock, by way of return of capital or otherwise (including, without

limitation, any distribution of cash, stock or other securities, property, options, evidence of indebtedness or any other assets by way

of a dividend, spin off, reclassification, corporate rearrangement, scheme of arrangement or other similar transaction, but, for the avoidance

of doubt, excluding any distribution of shares of Common Stock subject to Section 9(a), any distribution of Purchase Rights

(as defined below) subject to Section 9(c) and any Fundamental Transaction (as defined below) subject to Section 9(d))

(a “Distribution”) then, in each such case, the Holder shall be entitled to participate in such Distribution to the

same extent that the Holder would have participated therein if the Holder had held the number of shares of Common Stock acquirable upon

complete exercise of this Warrant (without regard to any limitations or restrictions on exercise of this Warrant, including without limitation,

the Maximum Percentage (as defined below)) immediately before the date on which a record is taken for such Distribution, or, if no such

record is taken, the date as of which the record holders of shares of Common Stock are to be determined for the participation in such

Distribution; provided that to the extent that the Holder’s right to participate in any such Distribution would result in the Holder

and the other Attribution Parties exceeding the Maximum Percentage, then the Holder shall not be entitled to participate in such Distribution

to such extent (and shall not be entitled to beneficial ownership of such shares of Common Stock as a result of such Distribution (and

beneficial ownership) to such extent) and the portion of such Distribution shall be held in abeyance for the benefit of the Holder until

such time or times as its right thereto would not result in the Holder and the other Attribution Parties exceeding the Maximum Percentage,

at which time or times the Holder shall be granted such Distribution (and any Distributions declared or made on such initial Distribution

or on any subsequent Distribution held similarly in abeyance) to the same extent as if there had been no such limitation.

If, at any time while this Warrant is outstanding, the Company grants, issues or sells any Options, Convertible Securities or rights to

purchase stock, warrants, securities or other property, in each case pro rata to the record holders of any class of Common Stock (the

“Purchase Rights”), then the Holder will be entitled to acquire, upon the terms applicable to such Purchase Rights,

the aggregate Purchase Rights which the Holder could have acquired if the Holder had held the number of shares of Common Stock acquirable

upon complete exercise of this Warrant (without regard to any limitations or restrictions on exercise of this Warrant, including without

limitation, the Maximum Percentage) immediately before the date on which a record is taken for the grant, issuance or sale of such Purchase

Rights, or, if no such record is taken, the date as of which the record holders of Common Stock are to be determined for the grant, issuance

or sale of such Purchase Rights; provided that to the extent that the Holder’s right to participate in any such Purchase Right would

result in the Holder and the other Attribution Parties exceeding the Maximum Percentage, then the Holder shall not be entitled to participate

in such Purchase Right to such extent (and shall not be entitled to beneficial ownership of such Common Stock as a result of such Purchase

Right (and beneficial ownership) to such extent) and such Purchase Right to such extent shall be held in abeyance for the benefit of the

Holder until such time or times as its right thereto would not result in the Holder and the other Attribution Parties exceeding the Maximum

Percentage, at which time or times the Holder shall be granted such right (and any Purchase Right granted, issued or sold on such initial

Purchase Right or on any subsequent Purchase Right to be held similarly in abeyance) to the same extent as if there had been no such limitation.

As used in this Section 9(c), (i) “Options” means any rights, warrants or options to subscribe for or purchase

shares of Common Stock or Convertible Securities and (ii) “Convertible Securities” mean any stock or securities (other

than Options) directly or indirectly convertible into or exercisable or exchangeable for shares of Common Stock.

(d) Fundamental Transactions. If,

at any time while this Warrant is outstanding (i) the Company effects any merger or consolidation of the Company with or into another

Person, in which the Company is not the surviving entity or in which the stockholders of the Company immediately prior to such merger

or consolidation do not own, directly or indirectly, at least 50% of the voting power of the surviving entity immediately after such merger

or consolidation, (ii) the Company effects any sale to another Person of all or substantially all of its assets in one transaction

or a series of related transactions, (iii) pursuant to any tender offer or exchange offer (whether by the Company or another Person),

holders of capital stock tender shares representing more than 50% of the voting power of the capital stock of the Company and the Company

or such other Person, as applicable, accepts such tender for payment, (iv) the Company consummates a stock purchase agreement or

other business combination (including, without limitation, a reorganization, recapitalization, spin-off or scheme of arrangement) with

another Person whereby such other Person acquires more than 50% of the voting power of the capital stock of the Company (except for any

such transaction in which the stockholders of the Company immediately prior to such transaction maintain, in substantially the same proportions,

the voting power of such Person immediately after the transaction), or (v) the Company effects any reclassification of the Common

Stock or any compulsory share exchange pursuant to which the Common Stock is effectively converted into or exchanged for other securities,

cash or property (other than as a result of a subdivision or combination of shares of Common Stock covered by Section 9(a) above)

and, in connection with or following such reclassification or share exchange, any Person or Group acquires more than 50% of the voting

power of the capital stock of the Company or any successor entity (in any such case, a “Fundamental Transaction”),

then following such Fundamental Transaction the Holder shall have the right to receive, upon exercise of this Warrant, the same amount

and kind of securities, cash or property as it would have been entitled to receive upon the occurrence of such Fundamental Transaction

if it had been, immediately prior to such Fundamental Transaction, the holder of the number of Warrant Shares then issuable upon exercise

in full of this Warrant (including any Distributions or Purchase Rights then held in abeyance pursuant to Sections 9(b) or

9(c) above) without regard to any limitations on exercise contained herein (the “Alternate Consideration”).

The Company shall not effect any Fundamental Transaction in which the Company is not the surviving entity or the Alternate Consideration

includes securities of another Person unless (i) the Alternate Consideration is solely cash and the Company provides for the simultaneous

“cashless exercise” of this Warrant pursuant to Section 10 below or (ii) prior to or simultaneously with

the consummation thereof, any successor to the Company, surviving entity or other Person (including any purchaser of assets of the Company)

shall assume the obligation to deliver to the Holder such Alternate Consideration as, in accordance with the foregoing provisions, the

Holder may be entitled to receive, and the other obligations under this Warrant. The provisions of this paragraph (d) shall similarly

apply to subsequent transactions analogous to a Fundamental Transaction. If the Company undertakes a Fundamental Transaction in which

the Company is not the surviving entity and the Alternate Consideration includes securities of another Person, then the Company shall

provide that, prior to or simultaneously with the consummation of such Fundamental Transaction, any successor to the Company, surviving

entity or other Person (including any purchaser of assets of the Company) (“the Successor Entity”) shall assume the

obligation to deliver to the Holder such Alternate Consideration as the Holder is entitled to receive in accordance with the foregoing

provisions, and to assume the other obligations under this Warrant. The provisions of this paragraph (d) shall similarly apply to

subsequent transactions analogous to a Fundamental Transaction.

Notwithstanding anything

to the contrary, in the event of a Fundamental Transaction, the Company or any Successor Entity shall, at the Holder’s option, exercisable

at any time concurrently with, or within thirty (30) days after, the consummation of the Fundamental Transaction (or, if later, the date

of the public announcement of the applicable Fundamental Transaction), purchase this Warrant from the Holder by paying to the Holder an

amount of cash equal to the Black Scholes Value (as defined below) of the remaining unexercised portion of this Warrant on the date of

the consummation of such Fundamental Transaction; provided, however, that, if the Fundamental Transaction is not within the Company’s

control, including a transaction that is not approved by the Company’s board of directors, then the Holder shall only be entitled

to receive from the Company or any Successor Entity the same type or form of consideration (and in the same proportion) delivered in the

Fundamental Transaction. “Black Scholes Value” means the value of this Warrant based on the Black-Scholes Option Pricing

Model obtained from the “OV” function on Bloomberg determined as of the day of consummation of the applicable Fundamental

Transaction for pricing purposes and reflecting (A) a risk-free interest rate corresponding to the U.S. Treasury rate for a period

equal to the time between the date of the public announcement of the applicable Fundamental Transaction and the Termination Date, (B) an

expected volatility equal to the 100 day volatility obtained from the HVT function on Bloomberg (determined utilizing a 365 day annualization

factor) as of the Trading Day immediately following the public announcement of the applicable Fundamental Transaction, (C) the underlying

price per share used in such calculation shall be the last VWAP immediately prior to the consummation of such Fundamental Transaction,

(D) a remaining option time equal to the time between the date of the public announcement of the applicable Fundamental Transaction

and the Termination Date and (E) a zero cost of borrow. The payment of the Black Scholes Value will be made by wire transfer of immediately

available funds within five Trading Days of the Holder’s election (or, if later, on the effective date of the Fundamental Transaction).

The terms of any agreement

pursuant to which a Fundamental Transaction is effected shall include terms requiring any such successor or surviving entity to comply

with the provisions of this Section 9(d) and ensuring that this Warrant (or any such replacement security) will be similarly

adjusted upon any subsequent Fundamental Transaction. The Company shall cause any Successor Entity to assume in writing all of the obligations

of the Company under this Warrant in accordance with the provisions of this Section 9(d) pursuant to written agreements

in form and substance reasonably satisfactory to and approved by the Holder (without unreasonable delay) prior to such Fundamental Transaction

and shall, at the option of the Holder, deliver to the Holder in exchange for this Warrant a security of the Successor Entity evidenced

by a written instrument substantially similar in form and substance to this Warrant which is exercisable for a corresponding number of

shares of capital stock of such Successor Entity (or its parent entity) equivalent to the shares of Common Stock acquirable and receivable

upon exercise of this Warrant (without regard to any limitations on the exercise of this Warrant) prior to such Fundamental Transaction,

and with an exercise price which applies the exercise price hereunder to such shares of capital stock (but taking into account the relative

value of the shares of Common Stock pursuant to such Fundamental Transaction and the value of such shares of capital stock, such adjustments

to the number of shares of capital stock and such exercise price being for the purpose of protecting the economic value of this Warrant

immediately prior to the consummation of such Fundamental Transaction), and which is reasonably satisfactory in form and substance to

the Holder. Upon the occurrence of any such Fundamental Transaction, the Successor Entity shall succeed to, and be substituted for the

Company (so that from and after the date of such Fundamental Transaction, the provisions of this Warrant referring to the “Company”

shall refer instead to the Successor Entity), and may exercise every right and power of the Company and shall assume all of the obligations

of the Company under this Warrant with the same effect as if such Successor Entity had been named as the Company herein. Notwithstanding

the foregoing, and without limiting Section 11 hereof, the Holder may elect, at its sole option, by delivery of written notice

to the Company to waive this Section 9(d) to permit a Fundamental Transaction without the assumption of this Warrant.

(e) Number of Warrant

Shares. Simultaneously with any adjustment to the Number of Warrant Shares pursuant to Section 9, the Exercise Price shall

be increased or decreased proportionately, so that after such adjustment the aggregate Exercise Price payable hereunder for the increased

or decreased Number of Warrant Shares shall be the same as the aggregate Exercise Price in effect immediately prior to such adjustment.

Notwithstanding the foregoing, in no event may the Exercise Price be adjusted below the par value of the Common Stock then in effect.

(f) Calculations.

All calculations under this Section 9 shall be made to the nearest one-tenth of one cent or the nearest share in accordance

with Section 12.

(g) Notice of Adjustments.

Upon the occurrence of each adjustment pursuant to this Section 9, the Company at its expense will promptly compute such adjustment,

in good faith, in accordance with the terms of this Warrant and prepare a certificate setting forth such adjustment, including a statement

of the adjusted Exercise Price and adjusted number or type of Warrant Shares or other securities issuable upon exercise of this Warrant

(as applicable), describing the transactions giving rise to such adjustments and showing in detail the facts upon which such adjustment

is based. The Company will promptly deliver a copy of each such certificate to the Holder and to the Transfer Agent.

(h) Notice of Corporate

Events. If, while this Warrant is outstanding, the Company (i) declares a dividend or any other distribution of cash, securities

or other property in respect of its Common Stock, including, without limitation, any granting of rights or warrants to subscribe for or

purchase any capital stock of the Company or any subsidiary, (ii) authorizes or approves, enters into any agreement contemplating

or solicits stockholder approval for any Fundamental Transaction or (iii) authorizes the voluntary dissolution, liquidation or winding

up of the affairs of the Company, then, except if such notice and the contents thereof shall be deemed to constitute material non-public

information, the Company shall deliver to the Holder a notice of such transaction at least ten (10) days prior to the applicable

record or effective date on which a Person would need to hold Common Stock in order to participate in or vote with respect to such transaction;

provided, however, that the failure to deliver such notice or any defect therein shall not affect the validity of the corporate action

required to be described in such notice. In addition, if while this Warrant is outstanding, the Company authorizes or approves, enters

into any agreement contemplating or solicits stockholder approval for any Fundamental Transaction contemplated by Section 9(d),

other than a Fundamental Transaction under clause (iii) of Section 9(d), then, except if such notice and the contents

thereof shall be deemed to constitute material non-public information, the Company shall deliver to the Holder a notice of such Fundamental

Transaction at least ten (10) days prior to the date such Fundamental Transaction is consummated.

(i) Notice of Milestone

Event. Promptly following (and in any event within one (1) Trading Day after) the occurrence of the Milestone Event, the

Company shall deliver written notice thereof to the Holder at the electronic mail address previously provided by the Holder to the Company

(or, if no such address has been provided, at such address as may appear in the Warrant Register or such other address as the Holder shall

have specified by written notice to the Company). The failure to deliver such notice or any defect therein shall not affect the validity

of the Milestone Event or the commencement of the Termination Date as set forth in the definition thereof;. Any such failure shall not

impair the Holder's right to exercise this Warrant during the applicable exercise period.

(j) Voluntary Adjustment

By Company. Subject to the rules and regulations of the Principal Trading Market, the Company may at any time during the term

of this Warrant, reduce the then-current Exercise Price to any amount and for any period of time deemed appropriate by the board of directors

of the Company.

10. Payment of Exercise Price. This Warrant

may only be exercised for cash; provided, however, if at the time of exercise hereof there is no effective Registration Statement registering,

with a current prospectus available for, the issuance of the Warrant Shares to the Holder, then this Warrant may be exercised, in whole

or in part, at such time by means of a “cashless exercise.” In the event of a “cashless exercise,” the Company

shall issue to the Holder the number of Warrant Shares (which term, for all purposes of this Section 10, shall be deemed to include

Pre-Funded Warrants, mutatis mutandis, if this Warrant is being exercised for Pre-Funded Warrants) in an exchange of securities

effected pursuant to Section 3(a)(9) of the Securities Act, determined as follows:

X = Y [(A-B)/A]

where:

“X” equals the

number of Warrant Shares to be issued to the Holder;

“Y” equals the

total number of Warrant Shares with respect to which this Warrant is then being exercised;

“A” equals the

Closing Sale Price as of the Trading Day immediately preceding the Exercise Date; and

“B” equals the

Exercise Price then in effect for the applicable Warrant Shares at the time of such exercise.

For purposes of Rule 144 promulgated under

the Securities Act, it is intended, understood and acknowledged that the Warrant Shares issued in a “cashless exercise” transaction

shall be deemed to have been acquired by the Holder, and the holding period for the Warrant Shares shall be deemed to have commenced,

on the Initial Exercise Date (provided that the Commission continues to take the position that such treatment is proper at the time of

such exercise). If the Registration Statement or another registration statement registering the issuance of Warrant Shares is, for any

reason, not effective at the time of exercise of this Warrant, then the Warrant may only be exercised through a cashless exercise, as

set forth in this Section 10. If the Warrant Shares are issued in such a cashless exercise, the Company acknowledges and agrees

that, in accordance with Section 3(a)(9) of the Securities Act, the Exercise Shares issued in such exercise shall take on the

registered characteristics of the Warrants being exercised and may be tacked on to the holding period of the Warrants being exercised.

Except as set forth in Section 5(b) (Buy-In) and Section 12 (No Fractional Shares), in no event will the

exercise of this Warrant be settled in cash.

11. Limitations on Exercise.

(a) Notwithstanding

anything to the contrary contained herein, the Company shall not effect the exercise of any portion of this Warrant (other than for Pre-Funded

Warrants), and the Holder of the Warrant shall not have the right to exercise any portion of the Warrant (other than for Pre-Funded Warrants),

and any such exercise shall be null and void ab initio and treated as if the exercise had not been made, to the extent that immediately

prior to or following such exercise, the Holder, together with the Attribution Parties, beneficially owns or would beneficially own as

determined in accordance with Section 13(d) of the Exchange Act and the rules promulgated thereunder, in excess of [4.99%][9.99%]

(the “Maximum Percentage”) of the Common Stock that would be issued and outstanding following such exercise. For purposes

of calculating beneficial ownership for determining whether the Maximum Percentage is or will be exceeded, the aggregate number of shares

of Common Stock held and/or beneficially owned by the Holder together with the Attribution Parties, shall include the number of shares

of Common Stock held and/or beneficially owned by the Holder together with the Attribution Parties plus the number of shares of Common

Stock issuable upon exercise of the relevant Warrant with respect to which the determination is being made but shall exclude the number

of shares of Common Stock which would be issuable upon (i) exercise of the remaining, unexercised Warrant held and/or beneficially

owned by the Holder or the Attribution Parties and (ii) exercise or conversion of the unexercised or unconverted portion of any

other securities of the Company held and/or beneficially owned by such Holder or any Attribution Party (including, without limitation,

any convertible notes, convertible stock or warrants) that are subject to a limitation on conversion or exercise analogous to the limitation

contained herein. For purposes of this Section 11(a), beneficial ownership of the Holder or the Attribution Parties shall,

except as set forth in the immediately preceding sentence, be calculated and determined in accordance with Section 13(d) of

the Exchange Act and the rules promulgated thereunder. For purposes of this Warrant, in determining the number of outstanding shares

of Common Stock, a Holder of this Warrant may rely on the number of outstanding shares of Common Stock as reflected in (1) the Company’s

most recent Form 10-K, Form 10-Q, Current Report on Form 8-K or other public filing with the Securities and Exchange Commission,

as the case may be, (2) a more recent public announcement by the Company or (3) any other notice by the Company or the Transfer

Agent setting forth the number of shares of Common Stock outstanding (such issued and outstanding shares, the “Reported Outstanding

Share Number”). For any reason at any time, upon the written or oral request of the Holder, the Company shall within three

(3) Trading Days confirm orally and in writing or by electronic mail to the Holder the number of shares of Common Stock then outstanding.

The Holder shall disclose to the Company the number of shares of Common Stock that it, together with the Attribution Parties, holds and/or

beneficially owns and has the right to acquire through the exercise of derivative securities and any limitations on exercise or conversion

analogous to the limitation contained herein contemporaneously or immediately prior to submitting an Exercise Notice. If the Company

receives an Exercise Notice from the Holder at a time when the actual number of outstanding shares of Common Stock is less than the Reported

Outstanding Share Number, the Company shall (i) notify the Holder in writing of the number of shares of Common Stock then outstanding

and, to the extent that such Exercise Notice would otherwise cause the Holder’s, together with the Attribution Parties’,

beneficial ownership, as determined pursuant to this Section 11(a), to exceed the Maximum Percentage, the Holder must notify

the Company of a reduced number of Warrant Shares to be purchased pursuant to such Exercise Notice (the number of shares by which such

purchase is reduced, the “Reduction Shares”) and (ii) as soon as reasonably practicable, the Company shall return

to the Holder any exercise price paid by the Holder for the Reduction Shares. In any case, the number of outstanding shares of Common

Stock shall be determined after giving effect to the conversion or exercise of securities of the Company, including this Warrant, by

the Holder and the Attribution Parties since the date as of which the Reported Outstanding Share Number was reported. If the issuance

of Common Stock to the Holder upon exercise of this Warrant results in the Holder, together with the Attribution Parties, being deemed

to beneficially own, in the aggregate, more than the Maximum Percentage of the number of outstanding shares of Common Stock (as determined

under Section 13(d) of the Exchange Act), the number of shares so issued by which the Holder’s, together with the Attribution

Parties’, aggregate beneficial ownership exceeds the Maximum Percentage (the “Excess Shares”) shall be deemed

null and void and shall be cancelled ab initio, and the Holder and/or the Attribution Parties shall not have the power to vote or to

transfer the Excess Shares. As soon as reasonably practicable after the issuance of the Excess Shares has been deemed null and void,

the Company shall return to the Holder the exercise price paid by the Holder for the Excess Shares. By written notice to the Company,

the Holder may from time to time increase or decrease the Maximum Percentage to any other percentage not in excess of 19.99% specified

in such notice; provided that any increase in the Maximum Percentage will not be effective until the sixty-first (61st) day after such

notice is delivered to the Company and shall not negatively affect any partial exercise effected prior to such change.

(b) This Section 11

shall not restrict the number of shares of Common Stock which a Holder or the Attribution Parties may receive or beneficially own in order

to determine the amount of securities or other consideration that such Holder or the Attribution Parties may receive in the event of a

Fundamental Transaction as contemplated in Section 9(d) of this Warrant. For purposes of clarity, the shares of Common

Stock issuable pursuant to the terms of this Warrant in excess of the Maximum Percentage shall not be deemed to be beneficially owned

by the Holder or the Attribution Parties for any purpose including for purposes of Section 13(d) of the Exchange Act or Section 16

of the Exchange Act and Rule 16a-1(a)(1) promulgated thereunder. No prior inability to exercise this Warrant pursuant to this

Section 11 shall have any effect on the applicability of the provisions of this Section 11 with respect to any

subsequent determination of exercisability. The provisions of this Section 11 shall be construed and implemented in a manner

otherwise than in strict conformity with the terms of this Section 11 to the extent necessary to correct this Section 11

or any portion of this Section 11 which may be defective or inconsistent with the intended beneficial ownership limitation

contained in this Section 11 or to make changes or supplements necessary or desirable to properly give effect to such limitation.

The limitation contained in this Section 11 may not be waived and shall apply to a successor holder of this Warrant.

12. No Fractional Shares or Pre-Funded Warrants.

No fractional Warrant Shares or fractional Pre-Funded Warrants will be issued in connection with any exercise of this Warrant. In lieu

of any fractional shares or fractional Pre-Funded Warrants that would otherwise be issuable, the number of Warrant Shares or Pre-Funded

Warrants to be issued shall be rounded down to the next whole number (after aggregating all Warrant Shares or Pre-Funded Warrants so issued)

and the Company shall pay the Holder in cash the fair market value (based on the Closing Sale Price) for any such fractional share or

fractional Pre-Funded Warrant.

13. Notices.

Any and all notices or other communications or deliveries hereunder (including, without limitation, any Exercise Notice) shall be in writing

and shall be deemed given and effective on the earliest of (i) the date of transmission, if such notice or communication is delivered

confirmed e-mail at the e-mail address specified in the books and records of the Transfer Agent prior to 5:30 P.M., New York City time,

on a Trading Day, (ii) the next Trading Day after the date of transmission, if such notice or communication is delivered via confirmed

e-mail at the e-mail address specified in the books and records of the Transfer Agent on a day that is not a Trading Day or later than

5:30 P.M., New York City time, on any Trading Day, (iii) the Trading Day following the date of mailing, if sent by nationally recognized

overnight courier service specifying next business day delivery, or (iv) upon actual receipt by the Person to whom such notice is

required to be given, if by hand delivery. Notice to the Company shall be delivered, mailed or sent to Altimmune, Inc., at 910 Clopper

Road, Suite 201S, Gaithersburg, MD 20878, Attention: Gregory Weaver and Robin Abrams, E-mail: gweaver@altimmune.com and rabrams@altimmune.com;

with a copy to Goodwin Procter LLP, 100 Northern Avenue, Boston, MA 02210, Attention: Joseph Theis, Justin Anslow E-mail: jtheis@goodwinlaw.com;

janslow@goodwinlaw.com.

14. Warrant Agent. The Company shall initially

serve as warrant agent under this Warrant. Upon thirty (30) days’ notice to the Holder, the Company may appoint a new warrant agent.

Any corporation into which the Company or any new warrant agent may be merged or any corporation resulting from any consolidation to which

the Company or any new warrant agent shall be a party or any corporation to which the Company or any new warrant agent transfers substantially

all of its corporate trust or shareholders services business shall be a successor warrant agent under this Warrant without any further

act. Any such successor warrant agent shall promptly cause notice of its succession as warrant agent to be mailed (by first class mail,

postage prepaid) to the Holder at the Holder’s last address as shown on the Warrant Register.

15. Miscellaneous.

(a) No Rights as

a Stockholder. Except as otherwise set forth in this Warrant, the Holder, solely in such Person’s capacity as a holder of this

Warrant, shall not be entitled to vote or receive dividends or be deemed the holder of share capital of the Company for any purpose, nor

shall anything contained in this Warrant be construed to confer upon the Holder, solely in such Person’s capacity as the Holder

of this Warrant, any of the rights of a stockholder of the Company or any right to vote, give or withhold consent to any corporate action

(whether any reorganization, issue of stock, reclassification of stock, consolidation, merger, amalgamation, conveyance or otherwise),

receive notice of meetings, receive dividends or subscription rights, or otherwise, prior to the issuance to the Holder of the Warrant

Shares which such Person is then entitled to receive upon the due exercise of this Warrant. In addition, nothing contained in this Warrant

shall be construed as imposing any liabilities on the Holder to purchase any securities (upon exercise of this Warrant or otherwise) or

as a stockholder of the Company, whether such liabilities are asserted by the Company or by creditors of the Company.

(b) Further Assurances.

Except as and to the extent waived or consented to by the Holder, the Company shall not by any action, including, without limitation,

amending its certificate or articles of incorporation or through any reorganization, transfer of assets, consolidation, merger, dissolution,

issue or sale of securities or any other voluntary action, avoid or seek to avoid the observance or performance of any of the terms of

this Warrant, but will at all times in good faith assist in the carrying out of all such terms and in the taking of all such actions as

may be necessary or appropriate to protect the rights of Holder as set forth in this Warrant against impairment. Without limiting the

generality of the foregoing, the Company will (a) not increase the par value of any Warrant Shares above the amount payable therefor

upon such exercise immediately prior to such increase in par value, (b) take all such action as may be necessary or appropriate in

order that the Company may validly and legally issue fully paid and non-assessable Warrant Shares upon the exercise of this Warrant, and

(c) use commercially reasonable efforts to obtain all such authorizations, exemptions or consents from any public regulatory body

having jurisdiction thereof as may be necessary to enable the Company to perform its obligations under this Warrant. Before taking any

action that would result in an adjustment in the number of Warrant Shares for which this Warrant is exercisable or in the Exercise Price,

the Company shall obtain all such authorizations or exemptions thereof, or consents thereto, as may be necessary from any public regulatory

body or bodies having jurisdiction thereof.

Assigns. This Warrant may not be assigned by the Company without the written consent of the Holder, except to a Successor Entity in

the event of a Fundamental Transaction. This Warrant shall be binding on and inure to the benefit of the Company and the Holder and their

respective successors and assigns. Subject to the preceding sentence, nothing in this Warrant shall be construed to give to any Person

other than the Company and the Holder any legal or equitable right, remedy or cause of action under this Warrant.

(d) Amendment and

Waiver. This Warrant may be amended or waived only in writing signed by the Company and the Holder, or their respective successors

and permitted assigns.. In the event an amendment or waiver is agreed to under this Section 15(d) or an adjustment to

the Exercise Price or otherwise is made by the Company under the terms of this Warrant with respect to another holder of a warrant comparable

to this Warrant and issued in the same transaction or series of related transactions in which this Warrant was issued, and such amendment,

waiver or adjustment would be favorable to the Holder, such amendment, waiver or adjustment shall apply to this Warrant.

(e) Acceptance.

Receipt of this Warrant by the Holder shall constitute acceptance of and agreement to all of the terms and conditions contained herein.

(f) Governing Law;

Jurisdiction. ALL QUESTIONS CONCERNING THE CONSTRUCTION, VALIDITY, ENFORCEMENT AND INTERPRETATION OF THIS WARRANT SHALL BE GOVERNED

BY AND CONSTRUED AND ENFORCED IN ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK WITHOUT REGARD TO THE PRINCIPLES OF CONFLICTS OF LAW

THEREOF. EACH OF THE COMPANY AND THE HOLDER HEREBY IRREVOCABLY SUBMITS TO THE EXCLUSIVE JURISDICTION OF THE STATE AND FEDERAL COURTS SITTING

IN THE CITY OF NEW YORK, BOROUGH OF MANHATTAN, FOR THE ADJUDICATION OF ANY DISPUTE HEREUNDER OR IN CONNECTION HEREWITH OR WITH ANY TRANSACTION

CONTEMPLATED HEREBY OR DISCUSSED HEREIN, AND HEREBY IRREVOCABLY WAIVES, AND AGREES NOT TO ASSERT IN ANY SUIT, ACTION OR PROCEEDING, ANY

CLAIM THAT IT IS NOT PERSONALLY SUBJECT TO THE JURISDICTION OF ANY SUCH COURT. EACH OF THE COMPANY AND THE HOLDER HEREBY IRREVOCABLY WAIVES

PERSONAL SERVICE OF PROCESS AND CONSENTS TO PROCESS BEING SERVED IN ANY SUCH SUIT, ACTION OR PROCEEDING BY MAILING A COPY THEREOF VIA

REGISTERED OR CERTIFIED MAIL OR OVERNIGHT DELIVERY (WITH EVIDENCE OF DELIVERY) TO SUCH PERSON AT THE ADDRESS IN EFFECT FOR NOTICES TO

IT AND AGREES THAT SUCH SERVICE SHALL CONSTITUTE GOOD AND SUFFICIENT SERVICE OF PROCESS AND NOTICE THEREOF. NOTHING CONTAINED HEREIN SHALL

BE DEEMED TO LIMIT IN ANY WAY ANY RIGHT TO SERVE PROCESS IN ANY MANNER PERMITTED BY LAW. EACH OF THE COMPANY AND THE HOLDER HEREBY WAIVES

ALL RIGHTS TO A TRIAL BY JURY.

(g) Remedies.

Each of the Holder and the Company acknowledges and agrees that any breach of this Warrant agreement by the other party may cause irreparable

harm to the non-breaching party and that money damages may be an inadequate remedy to protect the non-breaching party therefrom, and that

the non-breaching party shall be entitled to seek equitable relief, including injunction and specific performance, as a remedy for any

such breach. Such remedies shall not be deemed to be the exclusive remedies for any breach by a party or any of its representatives of

this Warrant agreement but shall be in addition to any and all other remedies available to the non-breaching party at law or in equity.

(h) Headings.

The headings herein are for convenience only, do not constitute a part of this Warrant and shall not be deemed to limit or affect any

of the provisions hereof.

(i) Severability.

If any part or provision of this Warrant is held unenforceable or in conflict with the applicable laws or regulations of any jurisdiction,

the invalid or unenforceable part or provisions shall be replaced with a provision which accomplishes, to the extent possible, the original

business purpose of such part or provision in a valid and enforceable manner, and the remainder of this Warrant shall remain binding upon

the parties hereto.

(j) Electronic Execution.

This Warrant may be delivered via facsimile, electronic mail (including pdf or any electronic signature complying with the U.S. federal

ESIGN Act of 2000, Uniform Electronic Transactions Act or other applicable law) or other transmission method and any Warrant so delivered

shall be deemed to have been duly and validly delivered and be valid and effective for all purposes.

[REMAINDER OF PAGE INTENTIONALLY LEFT BLANK]

IN WITNESS WHEREOF, the Company has caused this

Warrant to be duly executed by its authorized officer as of the date first indicated above.

ALTIMMUNE, INC.

By:

Name: Gregory Weaver

Title: Chief Financial Officer

SCHEDULE 1

FORM OF EXERCISE NOTICE

[To be executed by the Holder to purchase shares

of Common Stock under the Warrant.]

Ladies and Gentlemen:

(1) The undersigned is the Holder of Warrant No. __ (the

“Warrant”) issued by Altimmune, Inc., a Delaware corporation (the “Company”). Capitalized terms used herein

and not otherwise defined herein have the respective meanings set forth in the Warrant.

(2) The undersigned hereby exercises its right to purchase ________

Warrant Shares and _________ Pre-Funded Warrants pursuant to the Warrant.

(3) The Holder intends that payment of the Exercise Price shall

be made as (check one):

Cash Exercise

“Cashless Exercise” under Section 10 of the Warrant

Cash Exercise with respect to Pre-Funded Warrants

“Cashless Exercise” under Section 10 of the Warrant with respect to Pre-Funded Warrants

(4) The Holder shall pay the sum of $_____ in immediately available

funds to the Company in accordance with the terms of the Warrant.

¨ N/A due to “Cashless Exercise”

(5) Pursuant to this Exercise Notice, the Company shall deliver

to the Holder Warrant Shares or Pre-Funded Warrants determined in accordance with the terms of the Warrant. The Warrant Shares or Pre-Funded

Warrants shall be delivered (check one):

to the following DWAC Account Number: _______________________________

in book-entry form via a direct registration system

by physical delivery of a certificate to: ______________________________________________________

______________________________________________________

in restricted book-entry form in the Company’s share register

(6) By its delivery of this Exercise Notice, the undersigned represents

and warrants to the Company that in giving effect to the exercise evidenced hereby the Holder, together with the Attribution Parties,

will not beneficially own in excess of the number of shares of Common Stock (as determined in accordance with Section 13(d) of

the Securities Exchange Act of 1934, as amended) permitted to be owned under Section 11 of the Warrant to which this notice

relates.

Dated:

Name

of Holder:

By:

Name:

Title:

(Signature must conform in all respects to name

of Holder as specified on the face of the Warrant)

SCHEDULE 2

ASSIGNMENT FORM

[To assign the foregoing Warrant, execute this

form and supply required information.

Do not use this form to purchase shares.]

FOR VALUE RECEIVED, the foregoing Warrant and all rights evidenced

thereby are hereby assigned to

Name: _______________________________________________________________________________________

Address: _____________________________________________________________________________________

Phone Number: _______________________________________________________________________________

Email Address: _______________________________________________________________________________

Dated: _________________, ______

Holder’s Signature: ____________________________________________________________________________

Holder’s Address: _____________________________________________________________________________

SCHEDULE 3

FORM OF PRE-FUNDED WARRANT

EX-4.2 — EXHIBIT 4.2

EX-4.2

Filename: tm2612493d2_ex4-2.htm · Sequence: 4

Exhibit 4.2

The Company has filed a registration statement (including a prospectus)

with the SEC for the offering to which this communication relates. Before you invest, you should read the prospectus in that registration

statement and other documents the issuer has filed with the SEC for more complete information about the issuer and this offering. You

may get these documents for free by visiting EDGAR on the SEC Web site at www.sec.gov.

FORM OF PRE-FUNDED COMMON STOCK

PURCHASE WARRANT

ALTIMMUNE, INC.

Warrant Shares: [·]

Initial Exercise Date: [·], 2026

THIS PRE-FUNDED COMMON

STOCK PURCHASE WARRANT (the “Warrant”) certifies that, for value received, [·]

or its assigns (the “Holder”) is entitled, upon the terms and subject to the limitations on exercise and the conditions

hereinafter set forth, at any time on or after the date hereof (the “Initial Exercise Date”) until this Warrant is

exercised in full (the “Termination Date”) but not thereafter, to subscribe for and purchase from Altimmune, Inc.,

a Delaware corporation (the “Company”), up to [·]

shares (as subject to adjustment hereunder, the “Warrant Shares”) of Common Stock. The purchase price of one share

of Common Stock under this Warrant shall be equal to the Exercise Price, as defined in Section 2(b).

Section 1. Definitions. In addition to the

terms defined elsewhere in this Warrant, the following terms have the meanings indicated in this Section 1:

“Affiliate” means

any Person that, directly or indirectly through one or more intermediaries, controls or is controlled by or is under common control with

a Person, as such terms are used in and construed under Rule 405 under the Securities Act.

“Bid Price” means,

for any date, the price determined by the first of the following clauses that applies: (a) if the Common Stock is then listed or

quoted on a Trading Market, the bid price of the Common Stock for the time in question (or the nearest preceding date) on the Trading

Market on which the Common Stock is then listed or quoted as reported by Bloomberg L.P. (“Bloomberg”) (based on a Trading

Day from 9:30 a.m. (New York City time) to 4:02 p.m. (New York City time)), (b) if the Common Stock is then listed on OTCQB

or OTCQX, and OTCQB or OTCQX is not a Trading Market, the volume weighted average price of the Common Stock for such date (or the nearest

preceding date) on OTCQB or OTCQX as applicable, (c) if the Common Stock is not then listed or quoted for trading on OTCQB or OTCQX

and if prices for the Common Stock are then reported on the Pink Open Market (or a similar organization or agency succeeding to its functions

of reporting prices), the most recent bid price per share of the Common Stock so reported, or (d) in all other cases, the fair market

value of a share of Common Stock as determined by the Board of Directors in good faith.

“Board of Directors”

means the board of directors of the Company.

“Business Day” means

any day other than Saturday, Sunday or other day on which commercial banks in The City of New York are authorized or required by law to

remain closed; provided, however, for clarification, commercial banks shall not be deemed to be authorized or

required by law to remain closed due to “stay at home”, “shelter-in-place”, “non-essential employee” or

any other similar orders or restrictions or the closure of any physical branch locations at the direction of any governmental authority

so long as the electronic funds transfer systems (including for wire transfers) of commercial banks in The City of New York generally

are open for use by customers on such day.

“Commission” means

the United States Securities and Exchange Commission.

“Common Stock” means

the common stock of the Company, par value $0.0001 per share, and any other class of securities into which such securities may hereafter

be reclassified or changed.

“Common Stock Equivalents”

means any securities of the Company or the Subsidiaries which would entitle the holder thereof to acquire at any time shares of Common

Stock, including, without limitation, any debt, preferred stock, right, option, warrant or other instrument that is at any time convertible

into or exercisable or exchangeable for, or otherwise entitles the holder thereof to receive, Common Stock.

“Exchange Act” means

the Securities Exchange Act of 1934, as amended, and the rules and regulations promulgated thereunder.

“Person” means an

individual or corporation, partnership, trust, incorporated or unincorporated association, joint venture, limited liability company, joint

stock company, government (or an agency or subdivision thereof) or other entity of any kind.

“Registration Statement”

means the Company’s registration statement on Form S-3 (File No. 333-291329).

“Securities Act”

means the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder.

“Subsidiary” means

any subsidiary of the Company and shall, where applicable, also include any direct or indirect subsidiary of the Company formed or acquired

after the date hereof.

“Trading Day” means

a day on which the Common Stock is traded on a Trading Market.

“Trading Market”

means any of the following markets or exchanges on which the Common Stock is listed or quoted for trading on the date in question: the

NYSE American, the Nasdaq Capital Market, the Nasdaq Global Market, the Nasdaq Global Select Market, the New York Stock Exchange (or any

successors to any of the foregoing).

“Transfer

Agent” means Continental Stock Transfer & Trust Company, the current transfer agent of the Company, with a mailing

address of 1 State Street, 30th Floor, New York, NY 10004 and an email address of kfigueroa@continentalstock.com, and any successor transfer

agent of the Company.

“VWAP” means, for

any date, the price determined by the first of the following clauses that applies: (a) if the Common Stock is then listed or quoted

on a Trading Market, the daily volume weighted average price of the Common Stock for such date (or the nearest preceding date) on the

Trading Market on which the Common Stock is then listed or quoted as reported by Bloomberg L.P. (based on a Trading Day from 9:30 a.m. (New

York City time) to 4:02 p.m. (New York City time)), (b) if OTCQB or OTCQX is not a Trading Market, the volume weighted average

price of the Common Stock for such date (or the nearest preceding date) on OTCQB or OTCQX as applicable, (c) if the Common Stock

is not then listed or quoted for trading on OTCQB or OTCQX and if prices for the Common Stock are then reported on the Pink Open Market

(or a similar organization or agency succeeding to its functions of reporting prices), the most recent bid price per share of the Common

Stock so reported, or (d) in all other cases, the fair market value of a share of Common Stock as determined in good faith by the

Board of Directors.

Section 2. Exercise.

a) Exercise of Warrant.

Exercise of the purchase rights represented by this Warrant may be made, in whole or in part, at any time or times on or after the Initial

Exercise Date and on or before the Termination Date by delivery to the Company of a duly executed PDF copy submitted by e-mail (or e-mail attachment)

of the Notice of Exercise in the form annexed hereto (the “Notice of Exercise”). Within the earlier of (i) two

(2) Business Days and (ii) the number of Trading Days comprising the Standard Settlement Period (as defined in Section 2(d)(i) herein)

following the date of exercise as aforesaid, the Holder shall deliver the aggregate Exercise Price for the Warrant Shares specified in

the applicable Notice of Exercise by wire transfer or cashier’s check drawn on a United States bank unless the cashless exercise

procedure specified in Section 2(c) below is applicable and specified in the applicable Notice of Exercise. No ink-original Notice

of Exercise shall be required, nor shall any medallion guarantee (or other type of guarantee or notarization) of any Notice of Exercise

be required. Notwithstanding anything herein to the contrary, the Holder shall not be required to physically surrender this Warrant to

the Company until the Holder has purchased all of the Warrant Shares available hereunder and the Warrant has been exercised in full, in

which case, the Holder shall surrender this Warrant to the Company for cancellation within three (3) Trading Days of the date on

which the final Notice of Exercise is delivered to the Company. Partial exercises of this Warrant resulting in purchases of a portion

of the total number of Warrant Shares available hereunder shall have the effect of lowering the outstanding number of Warrant Shares purchasable

hereunder in an amount equal to the applicable number of Warrant Shares purchased. The Holder and the Company shall maintain records showing

the number of Warrant Shares purchased and the date of such purchases. This Warrant, as initially issued by the Company, is offered and

sold pursuant to the Registration Statement. As of the Initial Exercise Date, the Warrant Shares are issuable under the Registration Statement.

Accordingly, the Warrant and, assuming issuance pursuant to the Registration Statement or an exchange meeting the requirements of Section 3(a)(9) of

the Securities Act, the Warrant Shares are not “restricted securities” under Rule 144 promulgated under the Securities

Act as in effect on the Initial Exercise Date. The Company shall deliver any objection to any Notice of Exercise within one (1) Business

Day of receipt of such notice. The Holder and any assignee, by acceptance of this Warrant, acknowledge and agree that, by reason

of the provisions of this paragraph, following the purchase of a portion of the Warrant Shares hereunder, the number of Warrant Shares

available for purchase hereunder at any given time may be less than the amount stated on the face hereof.

b) Exercise Price. The

aggregate exercise price of this Warrant, except for a nominal exercise price of $0.001 per Warrant Share, was pre-funded to

the Company on or prior to the Initial Exercise Date and, consequently, no additional consideration (other than the nominal exercise price

of $0.001 per Warrant Share) shall be required to be paid by the Holder to any Person to effect any exercise of this Warrant. The Holder

shall not be entitled to the return or refund of all, or any portion, of such pre-paid aggregate exercise price under any circumstance

or for any reason whatsoever. The remaining unpaid exercise price per share of Common Stock under this Warrant shall be $0.001, subject

to adjustment hereunder (the “Exercise Price”).

c) Cashless Exercise. Notwithstanding

anything contained herein to the contrary, the Holder may, in its sole discretion, satisfy its obligation to pay the Exercise Price through

a “cashless exercise”, in which event the Company shall issue to the Holder the number of Warrant Shares in an exchange of

securities effected pursuant to Section 3(a)(9) of the Securities Act equal to the quotient obtained by dividing [(A-B) (X)]

by (A), where:

(A)

= as applicable: (i) the VWAP on the Trading Day immediately preceding the date of the applicable Notice of Exercise if such Notice of Exercise is (1) both executed and delivered pursuant to Section 2(a) hereof on a day that is not a Trading Day or (2) both executed and delivered pursuant to Section 2(a) hereof on a Trading Day prior to the opening of “regular trading hours” (as defined in Rule 600(b) of Regulation NMS promulgated under the federal securities laws) on such Trading Day, (ii) at the option of the Holder, either (y) the VWAP on the Trading Day immediately preceding the date of the applicable Notice of Exercise or (z) the Bid Price of the Common Stock on the principal Trading Market as reported by Bloomberg L.P. as of the time of the Holder’s execution of the applicable Notice of Exercise if such Notice of Exercise is executed during “regular trading hours” on a Trading Day and is delivered within two (2) hours thereafter (including until two (2) hours after the close of “regular trading hours” on a Trading Day) pursuant to Section 2(a) hereof or (iii) the VWAP on the date of the applicable Notice of Exercise if the date of such Notice of Exercise is a Trading Day and such Notice of Exercise is both executed and delivered pursuant to Section 2(a) hereof after the close of “regular trading hours” on such Trading Day;

(B)

= the Exercise Price of this Warrant, as adjusted hereunder; and

(X)

= the number of Warrant Shares that would be issuable upon exercise of this Warrant in accordance with the terms of this Warrant if such exercise were by means of a cash exercise rather than a cashless exercise.

If Warrant Shares are issued in such

a cashless exercise, the parties acknowledge and agree that in accordance with Section 3(a)(9) of the Securities Act, the Warrant

Shares shall take on the registered characteristics of the Warrants being exercised. In the event that a registration statement registering

the issuance of Warrant Shares is, for any reason, not effective at the time of exercise of this Warrant, then the Warrant may only be

exercised through a cashless exercise, as set forth in this Section 2(c). The Company agrees not to take any position contrary to

this Section 2(c).

d) Mechanics of Exercise.

i. Delivery of Warrant Shares Upon

Exercise. The Company shall cause the Warrant Shares purchased hereunder to be transmitted by the Transfer Agent to the Holder by

crediting the account of the Holder’s or its designee’s balance account with The Depository Trust Company through its Deposit

or Withdrawal at Custodian system (“DWAC”) if the Company is then a participant in such system and either (A) there

is an effective registration statement permitting the issuance of the Warrant Shares to or resale of the Warrant Shares by Holder, (B) the

Warrant Shares are eligible for resale by the Holder without volume or manner-of-sale restrictions pursuant to Rule 144 promulgated

under the Securities Act or (C) this Warrant is being exercised via cashless exercise, and otherwise by either (x) issuance

of the Warrant Shares in the name of the Holder or its designee in restricted book-entry form in the Company’s share register or

(y) physical delivery of a certificate, registered in the Company’s share register in the name of the Holder or its designee,

for the number of Warrant Shares to which the Holder is entitled pursuant to such exercise to the address specified by the Holder in the

Notice of Exercise by the date that is the earliest of (i) two (2) Business Days after the delivery to the Company of the Notice

of Exercise, (ii) one (1) Business Day after delivery of the aggregate Exercise Price to the Company and (iii) the number

of Trading Days comprising the Standard Settlement Period after the delivery to the Company of the Notice of Exercise (such date, the

“Warrant Share Delivery Date”). Upon delivery of the Notice of Exercise, the Holder shall be deemed for all corporate

purposes to have become the holder of record of the Warrant Shares with respect to which this Warrant has been exercised, irrespective

of the date of delivery of the Warrant Shares, provided that payment of the aggregate Exercise Price (other than in the case of a cashless

exercise) is received within the earlier of (i) two (2) Business Days and (ii) the number of Trading Days comprising the

Standard Settlement Period following delivery of the Notice of Exercise. The Company agrees to maintain a transfer agent that is a participant

in the FAST program so long as this Warrant remains outstanding and exercisable. As used herein, “Standard Settlement Period”

means the standard settlement period, expressed in a number of Trading Days, on the Company’s primary Trading Market with respect

to the Common Stock as in effect on the date of delivery of the Notice of Exercise.

ii. Delivery of New Warrants Upon

Exercise. If this Warrant shall have been exercised in part, the Company shall, at the request of a Holder and upon surrender of this

Warrant, at the time of delivery of the Warrant Shares, deliver to the Holder a new Warrant evidencing the rights of the Holder to purchase

the unpurchased Warrant Shares called for by this Warrant, which new Warrant shall in all other respects be identical with this Warrant.

iii. Rescission Rights. If

the Company fails to cause the Transfer Agent to transmit to the Holder the Warrant Shares pursuant to Section 2(d)(i) by the

Warrant Share Delivery Date, then the Holder will have the right to rescind such exercise.

iv. Compensation for Buy-In on

Failure to Timely Deliver Warrant Shares Upon Exercise. In addition to any other rights available to the Holder, if the Company fails

to cause the Transfer Agent to transmit to the Holder the Warrant Shares in accordance with the provisions of Section 2(d)(i) above

pursuant to an exercise on or before the Warrant Share Delivery Date (other than a failure caused by incorrect or incomplete information

provided by the Holder to the Company and subject to receipt of the aggregate exercise price for the applicable exercise (other than in

the case of a cashless exercise)), and if after such date the Holder is required by its broker to purchase (in an open market transaction

or otherwise) or the Holder’s brokerage firm otherwise purchases, shares of Common Stock to deliver in satisfaction of a sale by

the Holder of the Warrant Shares which the Holder anticipated receiving upon such exercise (a “Buy-In”), then the Company

shall (A) pay in cash to the Holder the amount, if any, by which (x) the Holder’s total purchase price (including brokerage

commissions, if any) for the shares of Common Stock so purchased exceeds (y) the amount obtained by multiplying (1) the number

of Warrant Shares that the Company was required to deliver to the Holder in connection with the exercise at issue times (2) the price

at which the sell order giving rise to such purchase obligation was executed, and (B) at the option of the Holder, either reinstate

the portion of the Warrant and equivalent number of Warrant Shares for which such exercise was not honored (in which case such exercise

shall be deemed rescinded) or deliver to the Holder the number of shares of Common Stock that would have been issued had the Company timely

complied with its exercise and delivery obligations hereunder. For example, if the Holder purchases Common Stock having a total purchase

price of $11,000 to cover a Buy-In with respect to an attempted exercise of shares of Common Stock with an aggregate sale price

giving rise to such purchase obligation of $10,000, under clause (A) of the immediately preceding sentence the Company shall be required

to pay the Holder $1,000. The Holder shall provide the Company written notice indicating the amounts payable to the Holder in respect

of the Buy-In and, upon request of the Company, evidence of the amount of such loss. Nothing herein shall limit a Holder’s right

to pursue any other remedies available to it hereunder, at law or in equity including, without limitation, a decree of specific performance

and/or injunctive relief with respect to the Company’s failure to timely deliver shares of Common Stock upon exercise of the Warrant

as required pursuant to the terms hereof. For the avoidance of doubt, the cash payment contemplated by clause (A) of this Section 2(d)(iv) constitutes

a damages remedy for the Company’s failure to timely deliver Warrant Shares and does not constitute a cash settlement of this Warrant

or any portion thereof; the Company’s primary obligation to deliver Warrant Shares upon exercise of this Warrant remains absolute

and unconditional, and no payment made pursuant to clause (A) of this Section 2(d)(iv) shall, except where the Holder elects

to rescind the exercise pursuant to clause (B), reduce, extinguish or otherwise affect the number of Warrant Shares issuable upon any

future exercise of this Warrant.

v. No Fractional Shares or Scrip.

No fractional shares or scrip representing fractional shares shall be issued upon the exercise of this Warrant. As to any fraction of

a share which the Holder would otherwise be entitled to purchase upon such exercise (after aggregating all Warrant Shares so issued),

the Company shall, at its election, either pay a cash adjustment in respect of such final fraction in an amount equal to such fraction

multiplied by the Exercise Price or round up to the next whole share.

vi. Charges, Taxes and Expenses.

Issuance of Warrant Shares shall be made without charge to the Holder for any issue or transfer tax or other incidental expense in respect

of the issuance of such Warrant Shares, all of which taxes and expenses shall be paid by the Company, and such Warrant Shares shall be

issued in the name of the Holder or in such name or names as may be directed by the Holder; provided, however,

that, in the event that Warrant Shares are to be issued in a name other than the name of the Holder, this Warrant when surrendered for

exercise shall be accompanied by the Assignment Form attached hereto duly executed by the Holder and the Company may require, as

a condition thereto, the payment of a sum sufficient to reimburse it for any transfer tax incidental thereto. The Company shall pay all

Transfer Agent fees required for same-day processing of any Notice of Exercise and all fees to the Depository Trust Company

(or another established clearing corporation performing similar functions) required for same-day electronic delivery of the

Warrant Shares.

vii. Closing of Books. The

Company will not close its stockholder books or records in any manner which prevents the timely exercise of this Warrant, pursuant to

the terms hereof.

e) Holder’s Exercise

Limitations. The Company shall not effect any exercise of this Warrant, and a Holder shall not have the right to exercise any portion

of this Warrant, pursuant to Section 2 or otherwise, to the extent that after giving effect to such issuance after exercise as set

forth on the applicable Notice of Exercise, the Holder (together with the Holder’s Affiliates, and any other Persons acting as a

group together with the Holder or any of the Holder’s Affiliates (such Persons, “Attribution Parties”)), would

beneficially own in excess of the Beneficial Ownership Limitation (as defined below). For purposes of the foregoing sentence, the

number of shares of Common Stock beneficially owned by the Holder and its Affiliates and Attribution Parties shall include the number

of shares of Common Stock issuable upon exercise of this Warrant with respect to which such determination is being made, but shall exclude

the number of shares of Common Stock which would be issuable upon (i) exercise of the remaining, nonexercised portion of this Warrant

beneficially owned by the Holder or any of its Affiliates or Attribution Parties and (ii) exercise or conversion of the unexercised

or nonconverted portion of any other securities of the Company (including, without limitation, any other Common Stock Equivalents) subject

to a limitation on conversion or exercise analogous to the limitation contained herein beneficially owned by the Holder or any of its

Affiliates or Attribution Parties. Except as set forth in the preceding sentence, for purposes of this Section 2(e), beneficial

ownership shall be calculated in accordance with Section 13(d) of the Exchange Act and the rules and regulations promulgated

thereunder, it being acknowledged by the Holder that the Company is not representing to the Holder that such calculation is in compliance

with Section 13(d) of the Exchange Act and the Holder is solely responsible for any schedules required to be filed in accordance

therewith. To the extent that the limitation contained in this Section 2(e) applies, the determination of whether this Warrant

is exercisable (in relation to other securities owned by the Holder together with any Affiliates and Attribution Parties) and of which

portion of this Warrant is exercisable shall be in the sole discretion of the Holder, and the submission of a Notice of Exercise shall

be deemed to be the Holder’s determination of whether this Warrant is exercisable (in relation to other securities owned by the

Holder together with any Affiliates and Attribution Parties) and of which portion of this Warrant is exercisable, in each case subject

to the Beneficial Ownership Limitation, and the Company shall have no obligation to verify or confirm the accuracy of such determination.

In addition, a determination as to any group status as contemplated above shall be determined in accordance with Section 13(d) of

the Exchange Act and the rules and regulations promulgated thereunder. For purposes of this Section 2(e), in determining the

number of outstanding shares of Common Stock, a Holder may rely on the number of outstanding shares of Common Stock as reflected in (A) the

Company’s most recent periodic or annual report filed with the Commission, as the case may be, (B) a more recent public announcement

by the Company or (C) a more recent written notice by the Company or the Transfer Agent setting forth the number of shares of Common

Stock outstanding. Upon the written request of a Holder, the Company shall within one Trading Day confirm in writing to the Holder

the number of shares of Common Stock then outstanding. In any case, the number of outstanding shares of Common Stock shall be determined

after giving effect to the conversion or exercise of securities of the Company, including this Warrant, by the Holder or its Affiliates

or Attribution Parties since the date as of which such number of outstanding shares of Common Stock was reported. The “Beneficial

Ownership Limitation” shall be [4.99%]/[9.99%] of the number of shares of the Common Stock outstanding immediately after giving

effect to the issuance of shares of Common Stock issuable upon exercise of this Warrant. The Holder, upon written notice to the Company,

may increase or decrease the Beneficial Ownership Limitation provisions of this Section 2(e), provided that the Beneficial Ownership

Limitation in no event exceeds 19.99% of the number of shares of the Common Stock outstanding immediately after giving effect to the issuance

of shares of Common Stock upon exercise of this Warrant held by the Holder and the provisions of this Section 2(e) shall continue

to apply. Any increase in the Beneficial Ownership Limitation will not be effective until the 61st day after such notice

is delivered to the Company. The provisions of this paragraph shall be construed and implemented in a manner otherwise than in strict

conformity with the terms of this Section 2(e) to correct this paragraph (or any portion hereof) which may be defective or inconsistent

with the intended Beneficial Ownership Limitation herein contained or to make changes or supplements necessary or desirable to properly

give effect to such limitation. The limitations contained in this paragraph shall apply to a successor holder of this Warrant.

Section 3. Certain Adjustments.

a) Stock Dividends and Splits.

If the Company, at any time while this Warrant is outstanding: (i) pays a stock dividend or otherwise makes a distribution or distributions

on shares of its Common Stock or any other equity or equity equivalent securities payable in shares of Common Stock (which, for avoidance

of doubt, shall not include any shares of Common Stock issued by the Company upon exercise of this Warrant), (ii) subdivides outstanding

shares of Common Stock into a larger number of shares, (iii) combines (including by way of reverse stock split) outstanding shares

of Common Stock into a smaller number of shares, or (iv) issues by reclassification of shares of the Common Stock any shares of capital

stock of the Company, then in each case the Exercise Price shall be multiplied by a fraction of which the numerator shall be the number

of shares of Common Stock (excluding treasury shares, if any) outstanding immediately before such event and of which the denominator shall

be the number of shares of Common Stock outstanding immediately after such event, and the number of shares issuable upon exercise of this

Warrant shall be proportionately adjusted such that the aggregate Exercise Price of this Warrant shall remain unchanged. Any adjustment

made pursuant to this Section 3(a) shall become effective immediately after the record date for the determination of stockholders

entitled to receive such dividend or distribution and shall become effective immediately after the effective date in the case of a subdivision,

combination or re-classification.

b) Subsequent Rights Offerings.

In addition to any adjustments pursuant to Section 3(a) above, if at any time the Company grants, issues or sells any Common

Stock Equivalents or rights to purchase stock, warrants, securities or other property pro rata to the record holders of any class of shares

of Common Stock (the “Purchase Rights”), then the Holder will be entitled to acquire, upon the terms applicable to

such Purchase Rights, the aggregate Purchase Rights which the Holder could have acquired if the Holder had held the number of shares of

Common Stock acquirable upon complete exercise of this Warrant (without regard to any limitations on exercise hereof, including without

limitation, the Beneficial Ownership Limitation) immediately before the date on which a record is taken for the grant, issuance or sale

of such Purchase Rights, or, if no such record is taken, the date as of which the record holders of shares of Common Stock are to be determined

for the grant, issue or sale of such Purchase Rights (provided, however, that, to the extent that the Holder’s right to participate

in any such Purchase Right would result in the Holder exceeding the Beneficial Ownership Limitation, then the Holder shall not be entitled

to participate in such Purchase Right to such extent (or beneficial ownership of such shares of Common Stock as a result of such Purchase

Right to such extent) and such Purchase Right to such extent shall be held in abeyance for the Holder until such time, if ever, as its

right thereto would not result in the Holder exceeding the Beneficial Ownership Limitation).

c) Pro Rata Distributions.

During such time as this Warrant is outstanding, if the Company shall declare or make any dividend or other distribution of its assets

(or rights to acquire its assets) to holders of shares of Common Stock, by way of return of capital or otherwise (including, without limitation,

any distribution of cash, stock or other securities, property or options by way of a dividend, spin off, reclassification, corporate rearrangement,

scheme of arrangement or other similar transaction) (a “Distribution”), at any time after the issuance of this Warrant,

then, in each such case, the Holder shall be entitled to participate in such Distribution to the same extent that the Holder would have

participated therein if the Holder had held the number of shares of Common Stock acquirable upon complete exercise of this Warrant (without

regard to any limitations on exercise hereof, including without limitation, the Beneficial Ownership Limitation) immediately before the

date of which a record is taken for such Distribution, or, if no such record is taken, the date as of which the record holders of shares

of Common Stock are to be determined for the participation in such Distribution (provided, however, that, to the extent

that the Holder’s right to participate in any such Distribution would result in the Holder exceeding the Beneficial Ownership Limitation,

then the Holder shall not be entitled to participate in such Distribution to such extent (or in the beneficial ownership of any shares

of Common Stock as a result of such Distribution to such extent) and the portion of such Distribution shall be held in abeyance for the

benefit of the Holder until such time, if ever, as its right thereto would not result in the Holder exceeding the Beneficial Ownership

Limitation). To the extent that this Warrant has not been partially or completely exercised at the time of such Distribution, such portion

of the Distribution shall be held in abeyance for the benefit of the Holder until the Holder has exercised this Warrant.

d) Fundamental Transaction.

If, at any time while this Warrant is outstanding, (i) the Company, directly or indirectly, in one or more related transactions effects

any merger or consolidation of the Company with or into another Person, (ii) the Company or any Subsidiary, directly or indirectly,

effects any sale, lease, license, assignment, transfer, conveyance or other disposition of all or substantially all of its assets in one

or a series of related transactions, (iii) any, direct or indirect, purchase offer, tender offer or exchange offer (whether by the

Company or another Person) is completed pursuant to which holders of Common Stock are permitted to sell, tender or exchange their shares

for other securities, cash or property and has been accepted by the holders of (after giving effect to such transaction) more than 50%

of the outstanding Common Stock or more than 50% of the voting power of the common equity of the Company, (iv) the Company, directly

or indirectly, in one or more related transactions effects any reclassification, reorganization or recapitalization of the Common Stock

or any compulsory share exchange pursuant to which the Common Stock is effectively converted into or exchanged for other securities, cash

or property and, in connection with or following such reclassification, reorganization, recapitalization or share exchange, any Person

or group of Persons acquires more than 50% of the outstanding shares of Common Stock or more than 50% of the voting power of the common

equity of the Company, or (v) the Company, directly or indirectly, in one or more related transactions consummates a stock or share

purchase agreement or other business combination (including, without limitation, a reorganization, recapitalization, spin-off, merger

or scheme of arrangement) with another Person or group of Persons whereby such other Person or group acquires more than 50% of the outstanding

shares of Common Stock or more than 50% of the voting power of the common equity of the Company (each a “Fundamental Transaction”),

then, upon any subsequent exercise of this Warrant, the Holder shall have the right to receive, for each Warrant Share that would have

been issuable upon such exercise immediately prior to the occurrence of such Fundamental Transaction, at the option of the Holder (without

regard to any limitation in Section 2(e) on the exercise of this Warrant), the securities, cash and other consideration of the

successor or acquiring corporation (or the ultimate parent thereof) or of the Company, if it is the surviving corporation, and any additional

consideration (the “Alternate Consideration”) receivable as a result of such Fundamental Transaction by a holder of

the number of shares of Common Stock for which this Warrant is exercisable immediately prior to such Fundamental Transaction (without

regard to any limitation in Section 2(e) on the exercise of this Warrant). For purposes of any such exercise, the determination

of the Exercise Price shall be appropriately adjusted to apply to such Alternate Consideration based on the amount of Alternate Consideration

issuable in respect of one share of Common Stock in such Fundamental Transaction, and the Company shall apportion the Exercise Price among

the Alternate Consideration in a reasonable manner reflecting the relative value of any different components of the Alternate Consideration.

If holders of Common Stock are given any choice as to the securities, cash or property to be received in a Fundamental Transaction, then

the Holder shall be given the same choice as to the Alternate Consideration it receives upon any exercise of this Warrant following such

Fundamental Transaction. The Company shall cause any successor entity in a Fundamental Transaction in which the Company is not the survivor

(the “Successor Entity”) to assume in writing all of the obligations of the Company under this Warrant in accordance

with the provisions of this Section 3(d) pursuant to written agreements in form and substance reasonably satisfactory to the

Holder and approved by the Holder (without unreasonable delay) prior to such Fundamental Transaction and shall, at the option of the Holder,

deliver to the Holder in exchange for this Warrant a security of the Successor Entity evidenced by a written instrument substantially

similar in form and substance to this Warrant which is exercisable for a corresponding number of shares of capital stock of such Successor

Entity (or its parent entity) equivalent to the shares of Common Stock acquirable and receivable upon exercise of this Warrant (without

regard to any limitations on the exercise of this Warrant) prior to such Fundamental Transaction, and with an exercise price which applies

the exercise price hereunder to such shares of capital stock (but taking into account the relative value of the shares of Common Stock

pursuant to such Fundamental Transaction and the value of such shares of capital stock, such number of shares of capital stock and such

exercise price being for the purpose of protecting the economic value of this Warrant immediately prior to the consummation of such Fundamental

Transaction), and which is reasonably satisfactory in form and substance to the Holder. Upon the occurrence of any such Fundamental Transaction,

the Successor Entity shall succeed to, and be substituted for the Company (so that from and after the date of such Fundamental Transaction,

the provisions of this Warrant referring to the “Company” shall refer instead to the Successor Entity), and may exercise every

right and power of the Company and shall assume all of the obligations of the Company under this Warrant with the same effect as if such

Successor Entity had been named as the Company herein.

e) Calculations. All calculations

under this Section 3 shall be made to the nearest thousandth of a cent or the nearest 1/100th of a share, as the case may be. For

purposes of this Section 3, the number of shares of Common Stock deemed to be issued and outstanding as of a given date shall be

the sum of the number of shares of Common Stock (excluding treasury shares, if any) issued and outstanding.

f) Notice to Holder.

i. Adjustment to Exercise Price.

Whenever the Exercise Price is adjusted pursuant to any provision of this Section 3, the Company shall promptly deliver to the Holder

by email a notice setting forth the Exercise Price after such adjustment and any resulting adjustment to the number of Warrant Shares

and setting forth a brief statement of the facts requiring such adjustment.

ii. Notice to Allow Exercise by

Holder. If (A) the Company shall declare a dividend (or any other distribution in whatever form) on the Common Stock, (B) the

Company shall declare a special nonrecurring cash dividend on or a redemption of the Common Stock, (C) the Company shall authorize

the granting to all holders of the Common Stock rights or warrants to subscribe for or purchase any shares of capital stock of any class

or of any rights, (D) the approval of any stockholders of the Company shall be required in connection with any reclassification of

the Common Stock, any consolidation or merger to which the Company (or any of its Subsidiaries) is a party, any sale or transfer of all

or substantially all of its assets, or any compulsory share exchange whereby the Common Stock is converted into other securities, cash

or property, or (E) the Company shall authorize the voluntary or involuntary dissolution, liquidation or winding up of the affairs

of the Company, then, in each case, the Company shall cause to be delivered by email to the Holder at its last email address as it shall

appear upon the Warrant Register of the Company, at least 20 calendar days prior to the applicable record or effective date hereinafter

specified, a notice stating (x) the date on which a record is to be taken for the purpose of such dividend, distribution, redemption,

rights or warrants, or if a record is not to be taken, the date as of which the holders of the Common Stock of record to be entitled to

such dividend, distributions, redemption, rights or warrants are to be determined or (y) the date on which such reclassification,

consolidation, merger, sale, transfer or share exchange is expected to become effective or close, and the date as of which it is expected

that holders of the Common Stock of record shall be entitled to exchange their shares of the Common Stock for securities, cash or other

property deliverable upon such reclassification, consolidation, merger, sale, transfer or share exchange; provided that the failure to

deliver such notice or any defect therein or in the delivery thereof shall not affect the validity of the corporate action required to

be specified in such notice. To the extent that any notice provided in this Warrant constitutes, or contains, material, non-public information

regarding the Company or any of the Subsidiaries, the Company shall simultaneously file such notice with the Commission pursuant to a

Current Report on Form 8-K. The Holder shall remain entitled to exercise this Warrant during the period commencing on the date

of such notice to the effective date of the event triggering such notice except as may otherwise be expressly set forth herein.

Section 4. Transfer of Warrant.

a) Transferability. This

Warrant and all rights hereunder (including, without limitation, any registration rights) are transferable, in whole or in part, upon

delivery, at the principal office of the Company or its designated agent, of a written assignment of this Warrant substantially in the

form attached hereto duly executed by the Holder or its agent or attorney and funds sufficient to pay any transfer taxes payable upon

the making of such transfer. Upon such surrender and, if required, such payment, the Company shall execute and deliver a new Warrant or

Warrants in the name of the assignee or assignees, as applicable, and in the denomination or denominations specified in such instrument

of assignment, and shall issue to the assignor a new Warrant evidencing the portion of this Warrant not so assigned, and this Warrant

shall promptly be cancelled. Notwithstanding anything herein to the contrary, the Holder shall not be required to physically surrender

this Warrant to the Company unless the Holder has assigned this Warrant in full, in which case, the Holder shall surrender this Warrant

to the Company within three (3) Trading Days of the date on which the Holder delivers an assignment form to the Company assigning

this Warrant in full. The Warrant, if properly assigned in accordance herewith, may be exercised by a new holder for the purchase of Warrant

Shares without having a new Warrant issued.

b) New Warrants. This Warrant

may be divided or combined with other Warrants upon presentation hereof at the aforesaid office of the Company, together with a written

notice specifying the names and denominations in which new Warrants are to be issued, signed by the Holder or its agent or attorney. Subject

to compliance with Section 4(a), as to any transfer which may be involved in such division or combination, the Company shall execute

and deliver a new Warrant or Warrants in exchange for the Warrant or Warrants to be divided or combined in accordance with such notice.

All Warrants issued on transfers or exchanges shall be dated the initial issuance date of this Warrant and shall be identical with this

Warrant except as to the number of Warrant Shares issuable pursuant thereto.

c) Warrant Register. The

Company shall initially serve as warrant agent under this Warrant. Upon ten (10) days’ notice to the Holder, the Company may

appoint a new warrant agent. Any corporation into which the Company or any new warrant agent may be merged or any corporation resulting

from any consolidation to which the Company or any new warrant agent shall be a party or any corporation to which the Company or any new

warrant agent transfers substantially all of its corporate trust or shareholders services business shall be a successor warrant agent

under this Warrant without any further act. Any such successor warrant agent shall promptly cause notice of its succession as warrant

agent to be mailed (by first class mail, postage prepaid) to the Holder at the Holder’s last address as shown on the Warrant Register.

The Company shall register this Warrant, upon records to be maintained by the Company for that purpose (the “Warrant Register”),

in the name of the record Holder hereof from time to time. The Company may deem and treat the registered Holder of this Warrant as the

absolute owner hereof for the purpose of any exercise hereof or any distribution to the Holder, and for all other purposes, absent actual

notice to the contrary.

Section 5. Miscellaneous.

a) No Rights as Stockholder

Until Exercise; No Settlement in Cash. This Warrant does not entitle the Holder to any voting rights, dividends or other rights as

a stockholder of the Company prior to the exercise hereof as set forth in Section 2(d)(i), except as expressly set forth in Section 3.

Without limiting any rights of a Holder to receive Warrant Shares on a “cashless exercise” pursuant to Section 2(c) or

to receive cash payments constituting damages pursuant to Section 2(d)(iv) herein or cash in lieu of fractional shares pursuant

to Section 2(d)(v), in no event shall the Company be required to net cash settle an exercise of this Warrant.

b) Loss, Theft, Destruction

or Mutilation of Warrant. The Company covenants that upon receipt by the Company of evidence reasonably satisfactory to it of the

loss, theft, destruction or mutilation of this Warrant or any stock certificate relating to the Warrant Shares, and in case of loss, theft

or destruction, of indemnity or security reasonably satisfactory to it (which, in the case of the Warrant, shall not include the posting

of any bond), and upon surrender and cancellation of such Warrant or stock certificate, if mutilated, the Company will make and deliver

a new Warrant or stock certificate of like tenor and dated as of such cancellation, in lieu of such Warrant or stock certificate.

c) Saturdays, Sundays, Holidays, etc.

If the last or appointed day for the taking of any action or the expiration of any right required or granted herein shall not be a Business

Day, then such action may be taken or such right may be exercised on the next succeeding Business Day.

d) Authorized Shares.

The Company covenants that, during

the period the Warrant is outstanding, it will reserve from its authorized and unissued Common Stock a sufficient number of shares to

provide for the issuance of the Warrant Shares upon the exercise of any purchase rights under this Warrant. The Company further covenants

that its issuance of this Warrant shall constitute full authority to its officers who are charged with the duty of issuing the necessary

Warrant Shares upon the exercise of the purchase rights under this Warrant. The Company will take all such reasonable action as may be

necessary to assure that such Warrant Shares may be issued as provided herein without violation of any applicable law or regulation, or

of any requirements of the Trading Market upon which the Common Stock may be listed. The Company covenants that all Warrant Shares which

may be issued upon the exercise of the purchase rights represented by this Warrant will, upon exercise of the purchase rights represented

by this Warrant and payment for such Warrant Shares in accordance herewith, be duly authorized, validly issued, fully paid and nonassessable

and free from all taxes, liens and charges created by the Company in respect of the issue thereof (other than taxes in respect of any

transfer occurring contemporaneously with such issue).

Except and to the extent as waived

or consented to by the Holder, the Company shall not by any action, including, without limitation, amending its certificate of incorporation

or through any reorganization, transfer of assets, consolidation, merger, dissolution, issue or sale of securities or any other voluntary

action, avoid or seek to avoid the observance or performance of any of the terms of this Warrant, but will at all times in good faith

assist in the carrying out of all such terms and in the taking of all such actions as may be necessary or appropriate to protect the rights

of Holder as set forth in this Warrant against impairment. Without limiting the generality of the foregoing, the Company will (i) not

increase the par value of any Warrant Shares above the amount payable therefor upon such exercise immediately prior to such increase in

par value, (ii) take all such action as may be necessary or appropriate in order that the Company may validly and legally issue fully

paid and nonassessable Warrant Shares upon the exercise of this Warrant and (iii) use commercially reasonable efforts to obtain all

such authorizations, exemptions or consents from any public regulatory body having jurisdiction thereof, as may be, necessary to enable

the Company to perform its obligations under this Warrant.

Before taking any action which would

result in an adjustment in the number of Warrant Shares for which this Warrant is exercisable or in the Exercise Price, the Company shall

obtain all such authorizations or exemptions thereof, or consents thereto, as may be necessary from any public regulatory body or bodies

having jurisdiction thereof.

e) Governing Law. All questions

concerning the construction, validity, enforcement and interpretation of this Warrant shall be governed by and construed and enforced

in accordance with the internal laws of the State of New York, without regard to the principles of conflicts of law thereof. Each party

agrees that all legal proceedings concerning the interpretations, enforcement and defense of the transactions contemplated by this Warrant

(whether brought against a party hereto or their respective affiliates, directors, officers, shareholders, partners, members, employees

or agents) shall be commenced exclusively in the state and federal courts sitting in the City of New York. Each party hereby irrevocably

submits to the exclusive jurisdiction of the state and federal courts sitting in the City of New York, Borough of Manhattan for the adjudication

of any dispute hereunder or in connection herewith or with any transaction contemplated hereby or discussed herein, and hereby irrevocably

waives, and agrees not to assert in any suit, action or proceeding, any claim that it is not personally subject to the jurisdiction of

any such court, that such suit, action or proceeding is improper or is an inconvenient venue for such proceeding. Each party hereby irrevocably

waives personal service of process and consents to process being served in any such suit, action or proceeding by mailing a copy thereof

via registered or certified mail or overnight delivery (with evidence of delivery) to such party at the address in effect for notices

to it under this Warrant and agrees that such service shall constitute good and sufficient service of process and notice thereof. Nothing

contained herein shall be deemed to limit in any way any right to serve process in any other manner permitted by law. If either party

shall commence an action, suit or proceeding to enforce any provisions of this Warrant, the prevailing party in such action, suit or proceeding

shall be reimbursed by the other party for their reasonable attorneys’ fees and other costs and expenses incurred with the investigation,

preparation and prosecution of such action or proceeding.

f) RESERVED.

g) Nonwaiver and Expenses.

No course of dealing or any delay or failure to exercise any right hereunder on the part of Holder shall operate as a waiver of such right

or otherwise prejudice the Holder’s rights, powers or remedies. Without limiting any other provision of this Warrant, if the Company

willfully and knowingly fails to comply with any provision of this Warrant, which results in any material damages to the Holder, the Company

shall pay to the Holder such amounts as shall be sufficient to cover any costs and expenses including, but not limited to, reasonable

attorneys’ fees, including those of appellate proceedings, incurred by the Holder in collecting any amounts due pursuant hereto

or in otherwise enforcing any of its rights, powers or remedies hereunder.

h) Notices.

Any and all notices or other communications or deliveries to be provided by the Holders hereunder including, without limitation, any Notice

of Exercise, shall be in writing and delivered personally, by e-mail, or sent by a nationally recognized overnight courier service,

addressed to the Company, at 910 Clopper Road, Suite 201S, Gaithersburg, MD 20878, Attention: Gregory Weaver, email address: gweaver@altimmune.com,

or such other email address or address as the Company may specify for such purposes by notice to the Holders. Any

and all notices or other communications or deliveries to be provided by the Company hereunder shall be in writing and delivered personally,

by e-mail, or sent by a nationally recognized overnight courier service addressed to each Holder at the e-mail address

or address of such Holder appearing on the books of the Company. Any notice or other communication or deliveries hereunder shall be deemed

given and effective on the earliest of (i) the time of transmission, if such notice or communication is delivered via e-mail at

the e-mail address set forth in this Section prior to 5:30 p.m. (New York City time) on any date, (ii) the next

Trading Day after the time of transmission, if such notice or communication is delivered via e-mail at the e-mail address

set forth in this Section on a day that is not a Trading Day or later than 5:30 p.m. (New York City time) on any Trading Day,

(iii) the second Trading Day following the date of mailing, if sent by U.S. nationally recognized overnight courier service, or (iv) upon

actual receipt by the party to whom such notice is required to be given. To the extent that any notice provided hereunder constitutes,

or contains, material, non-public information regarding the Company or any Subsidiaries, the Company shall simultaneously file

such notice with the Commission pursuant to a Current Report on Form 8-K.

i) Limitation of Liability.

No provision hereof, in the absence of any affirmative action by the Holder to exercise this Warrant to purchase Warrant Shares, and no

enumeration herein of the rights or privileges of the Holder, shall give rise to any liability of the Holder for the purchase price of

any Common Stock or as a stockholder of the Company, whether such liability is asserted by the Company or by creditors of the Company.

j) Remedies. The Holder,

in addition to being entitled to exercise all rights granted by law, including recovery of damages, will be entitled to specific performance

of its rights under this Warrant. The Company agrees that monetary damages would not be adequate compensation for any loss incurred by

reason of a breach by it of the provisions of this Warrant and hereby agrees to waive and not to assert the defense in any action for

specific performance that a remedy at law would be adequate.

k) Successors and Assigns.

Subject to applicable securities laws, this Warrant and the rights and obligations evidenced hereby shall inure to the benefit of and

be binding upon the successors and permitted assigns of the Company and the successors and permitted assigns of Holder. The provisions

of this Warrant are intended to be for the benefit of any Holder from time to time of this Warrant and shall be enforceable by the Holder

or holder of Warrant Shares.

l) Amendment. This Warrant

may be modified or amended, or the provisions hereof waived, only with the written consent of the Company and the Holder.

m) Severability. Wherever

possible, each provision of this Warrant shall be interpreted in such manner as to be effective and valid under applicable law, but if

any provision of this Warrant shall be prohibited by or invalid under applicable law, such provision shall be ineffective to the extent

of such prohibition or invalidity, without invalidating the remainder of such provisions or the remaining provisions of this Warrant.

n) Headings. The headings

used in this Warrant are for the convenience of reference only and shall not, for any purpose, be deemed a part of this Warrant.

o) Electronic Execution. This

Warrant may be delivered via facsimile, electronic mail (including pdf or any electronic signature complying with the U.S. federal ESIGN

Act of 2000, Uniform Electronic Transactions Act or other applicable law) or other transmission method and any Warrant so delivered shall

be deemed to have been duly and validly delivered and be valid and effective for all purposes.

********************

(Signature Page Follows)

IN WITNESS WHEREOF, the Company has caused this

Warrant to be executed by its officer thereunto duly authorized as of the date first above indicated.

ALTIMMUNE, INC.

By:

Name:

Title:

NOTICE OF EXERCISE

TO: ALTIMMUNE, INC.

(1) The undersigned hereby elects to purchase

________ Warrant Shares of the Company pursuant to the terms of the Pre-Funded Common Stock Purchase Warrant dated ______, and tenders

herewith payment of the exercise price in full, together with all applicable transfer taxes, if any.

(2) Payment shall take the form of (check

applicable box):

[ ] in lawful money of the United States;

[ ] pursuant to the cashless exercise

procedure set forth in subsection 2(c).

(3) Please issue said Warrant Shares

in the name of the undersigned or in such other name as is specified below:

_________________________________________________

The Warrant Shares shall be delivered to the following DWAC Account

Number:

_________________________________________________

[SIGNATURE OF HOLDER]

Name of Investing Entity: ________________________________________________________________________

Signature of Authorized Signatory of Investing Entity: _________________________________________________

Name of Authorized Signatory: ___________________________________________________________________

Title of Authorized Signatory: ____________________________________________________________________

Date: ________________________________________________________________________________________

ASSIGNMENT FORM

(To assign the foregoing Warrant, execute this

form and supply required information. Do not use this form to purchase shares.)

FOR VALUE RECEIVED, the foregoing Warrant and

all rights evidenced thereby are hereby assigned to:

Name:

(Please Print)

Address:

(Please Print)

Phone Number:

Email Address:

Dated: _______________ __, ______

Holder’s Signature:_______________________________

Holder’s Address:_______________________________

EX-5.1 — EXHIBIT 5.1

EX-5.1

Filename: tm2612493d2_ex5-1.htm · Sequence: 5

Exhibit 5.1

Goodwin Procter LLP

100 Northern Avenue

Boston, MA 02210

goodwinlaw.com

+1 617 570 1000

April 24, 2026

Altimmune, Inc.

910 Clopper Road, Suite 201S

Gaithersburg, MD 20878

Re: Securities Registered under Registration Statements on Form

S-3

We have acted as counsel to you in

connection with your filing of a Registration Statement on Form S-3 (File No. 333-291329), as amended, initially filed on

November 6, 2025 and declared effective on December 5, 2025 with the Securities and Exchange Commission (the

“Commission”), a Registration Statement on Form S-3 (File No. 333-285355) filed on February 27, 2025 and declared

effective on March 13, 2025 with the Commission and a Registration Statement on Form S-3MEF (File No. 333-295254) filed on April 22,

2026 and declared effective on April 22, 2026 with the Commission (collectively, the “Registration Statements”), each

pursuant to the Securities Act of 1933, as amended (the “Securities Act”), relating to the registration of the offer by

Altimmune, Inc., a Delaware corporation (the “Company”), of any combination of securities of the types specified

therein. Reference is made to our opinion letters dated November 6, 2025, February 28, 2025 and April 22, 2026 respectively, and

included as Exhibit 5.1 to the Registration Statements. We are delivering this supplemental opinion letter in connection with

the prospectus supplement (the “Prospectus Supplement”) filed on April 23, 2026 by the Company with the Commission

pursuant to Rule 424 under the Securities Act. The Prospectus Supplement relates to the offering by the Company of (i)

64,250,000 shares (the “Shares”) of the Company’s common stock, par value $0.0001 per share (the “Common

Stock”), (ii) pre-funded warrants (the “Pre-Funded Warrants”) to purchase up to 10,750,000 shares of Common Stock,

(iii) warrants (the “Common Warrants”, and together with the Pre-Funded Warrants, the “Warrants”) to

purchase up to 75,000,000 shares of Common Stock (or Pre-Funded Warrants, in lieu thereof), (iv) the shares of Common Stock issuable from

time to time upon exercise of any Pre-Funded Warrants (the “Pre-Funded Warrant Shares”) and (v) the shares of Common

Stock issuable from time to time upon exercise of the Common Warrants (the “Common Warrant Shares” and together with the

Pre-Funded Warrant Shares, the “Warrant Shares”), covered by the Registration Statements. The Shares and the Warrants

are being sold to the several underwriters named in, and pursuant to, an underwriting agreement among the Company and such

underwriters (the “Underwriting Agreement”).

We have reviewed such documents and made such

examination of law as we have deemed appropriate to give the opinions set forth below. We have relied, without independent verification,

on certificates of public officials and, as to matters of fact material to the opinions set forth below, on certificates of officers of

the Company. For purposes of the opinion set forth in paragraph 3 below, we have assumed that before the Warrant Shares are issued, the

Company does not issue shares of Common Stock or reduce the total number of shares of Common Stock the Company is authorized to issue

under its certificate of incorporation such that the number of unissued shares of Common Stock authorized under the Company’s certificate

of incorporation is less than the number of Warrant Shares.

Altimmune, Inc.

April 24, 2026

Page 2

The opinions set forth below are limited to the

Delaware General Corporation Law, and with respect to the opinion in paragraph 2, the law of the State of New York.

Based on the foregoing, we are of the opinion

that:

1. The Shares have been duly authorized and, when delivered and paid for in accordance with the terms of

the Underwriting Agreement, will be validly issued, fully paid and non-assessable.

2. The Warrants have been duly authorized and executed by the Company and, when delivered and paid for in

accordance with the terms of the Underwriting Agreement, will be valid and binding obligations of the Company.

3. Assuming sufficient authorized but unissued shares of Common Stock are available for issuance when the

Warrants are exercised, the Warrant Shares, when issued upon exercise of the Warrants in accordance with the terms of the Warrants, will

be validly issued, fully paid and non-assessable.

The opinions expressed above are subject to bankruptcy,

insolvency, fraudulent transfer, reorganization, moratorium and other similar laws of general application affecting the rights and remedies

of creditors and to general principles of equity.

This opinion letter and the opinions it contains

shall be interpreted in accordance with the Core Opinion Principles as published in 74 Business Lawyer 815 (Summer 2019).

We hereby consent to the inclusion of this opinion

as Exhibit 5.1 to the Current Report on Form 8-K and to the references to our firm under the caption “Legal Matters”

in the Registration Statements. In giving our consent, we do not admit that we are in the category of persons whose consent is required

under Section 7 of the Securities Act or the rules and regulations thereunder.

Very truly yours,

/s/ Goodwin Procter LLP

GOODWIN PROCTER LLP

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ALTIMMUNE, Inc.

Entity Central Index Key

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910 Clopper Road,

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Cover page.

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No definition available.

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For the EDGAR submission types of Form 8-K: the date of the report, the date of the earliest event reported; for the EDGAR submission types of Form N-1A: the filing date; for all other submission types: the end of the reporting or transition period. The format of the date is YYYY-MM-DD.

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No definition available.

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- Definition

The type of document being provided (such as 10-K, 10-Q, 485BPOS, etc). The document type is limited to the same value as the supporting SEC submission type, or the word 'Other'.

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No definition available.

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- Definition

Address Line 1 such as Attn, Building Name, Street Name

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Address Line 2 such as Street or Suite number

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Name of the City or Town

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Code for the postal or zip code

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Name of the state or province.

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No definition available.

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- Definition

A unique 10-digit SEC-issued value to identify entities that have filed disclosures with the SEC. It is commonly abbreviated as CIK.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 12

-Subsection b-2

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Indicate if registrant meets the emerging growth company criteria.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 12

-Subsection b-2

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Commission file number. The field allows up to 17 characters. The prefix may contain 1-3 digits, the sequence number may contain 1-8 digits, the optional suffix may contain 1-4 characters, and the fields are separated with a hyphen.

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No definition available.

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Two-character EDGAR code representing the state or country of incorporation.

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No definition available.

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The exact name of the entity filing the report as specified in its charter, which is required by forms filed with the SEC.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 12

-Subsection b-2

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The Tax Identification Number (TIN), also known as an Employer Identification Number (EIN), is a unique 9-digit value assigned by the IRS.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 12

-Subsection b-2

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Local phone number for entity.

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- Definition

Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 13e

-Subsection 4c

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Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 14d

-Subsection 2b

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Title of a 12(b) registered security.

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-Publisher SEC

-Name Exchange Act

-Number 240

-Section 12

-Subsection b

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- Definition

Name of the Exchange on which a security is registered.

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-Publisher SEC

-Name Exchange Act

-Number 240

-Section 12

-Subsection d1-1

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Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as soliciting material pursuant to Rule 14a-12 under the Exchange Act.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 14a

-Subsection 12

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- Definition

Trading symbol of an instrument as listed on an exchange.

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- Definition

Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as written communications pursuant to Rule 425 under the Securities Act.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Securities Act

-Number 230

-Section 425

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