Form 8-K

8-K — Theriva Biologics, Inc.

Accession: 0001104659-26-090064

Filed: 2026-08-04

Period: 2026-08-03

CIK: 0000894158

SIC: 2834 (PHARMACEUTICAL PREPARATIONS)

Item: Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers: Compensatory Arrangements of Certain Officers

Item: Submission of Matters to a Vote of Security Holders

Item: Financial Statements and Exhibits

Documents

8-K — tm2619846d1_8k.htm (Primary)

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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 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): August 3, 2026

THERIVA BIOLOGICS, INC.

(Exact name of registrant as specified in its charter)

Nevada

001-12584

13-3808303

(State or other jurisdiction of

incorporation)

(Commission File No.)

(IRS Employer Identification

No.)

9605 Medical Center Drive, Suite 270

Rockville, Maryland 20850

(Address of principal executive offices and zip

code)

(301) 417-4364

Registrant’s telephone number, including

area code

N/A

(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 (see General

Instruction A.2. below):

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

Soliciting material pursuant to Rule 14a-12(b) 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 $0.001 per share

TOVX

NYSE American

Indicate by check mark whether the registrant

is an emerging growth company as defined in in Rule 405 of the Securities Act of 1933 (17 CFR §230.405 of this chapter) or Rule 12b-2

of the Securities Exchange Act of 1934 (17 CFR §240.12b-2 of this chapter).

Emerging growth company ¨

If an emerging growth company, indicate by checkmark

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 5.02. Departure of Directors or Certain Officers; Election

of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers.

Amendment to 2020 Stock Incentive Plan

On August 3, 2026, Theriva Biologics, Inc. (the

“Company”) held its 2026 Annual Meeting of Stockholders (the “Annual Meeting”). At the Annual Meeting, the Company’s

stockholders approved an amendment (“Amendment No. 4”) to the Company’s 2020 Stock Incentive Plan (the “2020 Stock

Incentive Plan”) to (i) increase the number of shares of common stock that the Company will have authority to grant under the 2020

Stock Incentive Plan from 4,500,000 shares of common stock to 6,500,000 shares of common stock. A description of the 2020 Stock Incentive

Plan is set forth in the Company’s definitive proxy statement on Schedule 14A for the Annual Meeting (the “Definitive Proxy

Statement”), which was filed on June 29, 2026 with the Securities and Exchange Commission (the “Commission”), in the

section entitled “Proposal 3 - 2020 Plan Increase Proposal”. The description of Amendment No. 4 is qualified in its entirety

by reference to the full text of Amendment No. 4, a copy of which is included as an exhibit to this Current Report on Form 8-K and attached

to the Definitive Proxy Statement as Appendix A.

Item 5.07. Submission of Matters to a Vote of Security Holders.

On August 3, 2026, the Company held the Annual

Meeting where the Company’s stockholders voted on the following six (6) proposals and cast their votes as described below. These

matters are described in detail in the Definitive Proxy Statement.

The final results for Proposals 1, 2, 3, 4, 5

and 6 as set forth in the Definitive Proxy Statement were as follows:

Proposal 1 - Election of Directors.

The following four (4) individuals were elected

as directors, to serve until the Company’s next annual meeting of stockholders and until their respective successors have been duly

elected and qualified with the following votes:

Name of Director

Votes For

Withheld

Broker Non-Votes

Jeffrey J. Kraws

4,034,594

2,021,707

10,823,826

Steven A. Shallcross

4,030,358

2,025,943

10,823,826

John Monahan

4,003,454

2,052,847

10,823,826

Jeffrey Wolf

4,030,997

2,025,304

10,823,826

Proposal 2 – Auditor Ratification Proposal.

The stockholders ratified and approved the appointment

of BDO USA, P.C. as the Company’s independent registered public accounting firm for the year ending December 31, 2026 based on the

votes listed below:

Votes For

Votes Against

Abstentions

Broker Non-Votes

14,570,613

2,053,033

256,481

Proposal 3 - Amendment to the Company’s

2020 Stock Incentive Plan.

As further described above in Item 5.02 of this

Current Report on Form 8-K, the stockholders approved and adopted Amendment No. 4 to the 2020 Stock Incentive Plan, which amendment increased

the number of shares of common stock that the Company will have authority to grant under the 2020 Stock Incentive Plan from 4,500,000

shares to 6,500,000 shares of common stock. As a result, a maximum of 6,500,000 shares of common stock may be issued under the 2020 Stock

Incentive Plan, as amended. The results of the voting for this approved proposal are as follows:

Votes For

Votes Against

Abstentions

Broker Non-Votes

3,110,068

2,840,658

105,575

10,823,826

Proposal 4 – Approval of Amendment to

Increase the Number of Authorized Shares of Common Stock.

The stockholders approved an amendment to increase

the number of authorized shares of the Company’s common stock (the “Charter Amendment”), as described in the Definitive

Proxy Statement. As described in the Definitive Proxy Statement, the Board of Directors has discretion to determine whether to file the

Charter Amendment and may elect not to effect the amendment notwithstanding stockholder approval. The results of the voting for this approved

proposal are as follows:

Votes For

Votes Against

Abstentions

Broker Non-Votes

12,007,931

4,643,286

228,910

Proposal 5 – Approval of Issuance of Common Stock Upon Exercise

of Warrants.

The stockholders approved the issuance of shares of common stock upon

the exercise of outstanding warrants, as described in the Definitive Proxy Statement. The results of the voting for this approved proposal

are as follows:

Votes For

Votes Against

Abstentions

Broker Non-Votes

3,665,312

2,267,592

123,397

10,823,826

Proposal 6 – Approval of the Adjournment of the Annual Meeting.

The stockholders approved a proposal to adjourn the Annual Meeting

to a later date, if necessary, as described in the Definitive Proxy Statement. The results of the voting for this approved proposal are

as follows:

Votes For

Votes Against

Abstentions

Broker Non-Votes

12,012,234

4,297,352

570,541

Notwithstanding the approval of this proposal, because each of Proposals

1 through 5 received the requisite votes for approval at the Annual Meeting as convened, it was not necessary for the Company to adjourn

the Annual Meeting.

Item 9.01. Financial Statements and Exhibits.

(d)

Exhibits.

The following

exhibits are filed with this Current Report on Form 8-K:

Exhibit

Number

Description

10.1*

Amendment No. 4 to the Theriva Biologics, Inc. 2020 Stock Incentive Plan

104

Cover Page Interactive Data File (embedded within the XBRL document)

*Filed herewith

SIGNATURES

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.

Dated: August 4, 2026

THERIVA BIOLOGICS, INC.

By:

/s/ Steven A. Shallcross

Name:

Steven A. Shallcross

Title:

Chief Executive Officer

and Chief Financial Officer

EX-10.1 — EXHIBIT 10.1

EX-10.1

Filename: tm2619846d1_ex10-1.htm · Sequence: 2

Exhibit 10.1

AMENDMENT NO. 4

TO THE THERIVA BIOLOGICS, INC. 2020 STOCK INCENTIVE

PLAN

Dated: August 3, 2026

WHEREAS, the Board

of Directors (the “Board”) of Theriva Biologics, Inc. f/k/a Synthetic Biologics, Inc. (the “Company”) heretofore

established the Synthetic Biologics, Inc. 2020 Stock Incentive Plan (the “Plan”); and

WHEREAS, the Board

desires to amend the Plan to increase the maximum number of shares of common stock of the Company available for grants of Awards thereunder

(as of the date of this amendment, previously adopted the Plan) by an additional 2,000,000 shares of common stock to 6,500,000 shares

of common stock; and

WHEREAS, pursuant

to Section 17.2 of the Plan, the Board has the right to amend the Plan with respect to certain matters; and

WHEREAS, the Board

has approved and authorized this Amendment No. 4 to the Plan and has recommended that the stockholders of the Company approve this Amendment

No. 4;

NOW, THEREFORE, BE IT

RESOLVED, that the Plan is hereby amended, subject to and effective as of the date of stockholder approval hereof, in the following

particulars:

Subject to approval of the Company’s stockholders, Section 4(a) of the Plan is hereby amended by increasing the share references in such section by an additional 2,000,000 shares of common stock to 6,500,000 shares of common stock, so that Section 4(a) reads in its entirety as follows:

(a) Subject to adjustment pursuant to Section 4.3 hereof, the maximum

aggregate number of shares of Common Stock which may be issued under all Awards granted to Participants under the Plan shall be 6,500,000

shares (the “Initial Limit”), all of which may, but need not, be issued in respect of Incentive Stock Options.

Except as specifically set forth herein, the terms of the Plan shall be and remain unchanged, and the Plan as amended shall remain in full force and effect.

[Signature Page Follows]

IN WITNESS WHEREOF, the undersigned has

executed this Amendment No. 4 as evidence of its adoption by the Board on the date set forth above.

THERIVA BIOLOGICS, INC.

By:

/s/ Steven A. Shallcross

Name:

Steven A. Shallcross

Title:

Chief Executive Officer and Chief Financial Officer

Dated: August 3, 2026

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