Form 8-K

8-K — Atara Biotherapeutics, Inc.

Accession: 0001193125-26-219420

Filed: 2026-05-12

Period: 2026-05-12

CIK: 0001604464

SIC: 2836 (BIOLOGICAL PRODUCTS (NO DIAGNOSTIC SUBSTANCES))

Item: Financial Statements and Exhibits

Documents

8-K — atra-20260512.htm (Primary)

EX-99.1 (atra-ex99_1.htm)

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8-K

8-K (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): May 12, 2026

Atara Biotherapeutics, Inc.

(Exact name of Registrant as Specified in Its Charter)

Delaware

001-36548

46-0920988

(State or Other Jurisdiction

of Incorporation)

(Commission File Number)

(IRS Employer

Identification No.)

1280 Rancho Conejo Blvd

Thousand Oaks, California

91320

(Address of Principal Executive Offices)

(Zip Code)

Registrant’s Telephone Number, Including Area Code: (805) 623-4211

(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

ATRA

The Nasdaq Stock Market LLC

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 2.02 Results of Operations and Financial Condition.

On May 12, 2026, the Company announced certain financial results for the first quarter ended March 31, 2026. A copy of the Company’s press release, titled “Atara Biotherapeutics Announces First Quarter 2026 Financial Results and Operational Progress” is furnished as Exhibit 99.1 hereto.

The information set forth in this Item 2.02 and in the press release included as Exhibit 99.1 shall not be deemed “filed” for the purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or otherwise subject to the liabilities of Section 11 and 12(a)(2) of the Securities Act of 1933, as amended, and shall not be incorporated by reference into any filing with the U.S. Securities and Exchange Commission, whether made before or after the date hereof, except as shall be expressly set forth by specific reference in such filing.

Item 9.01 Financial Statements and Exhibits.

(d) Exhibits.

Exhibit No.

Description

99.1

Press Release, dated May 12, 2026

104

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

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.

ATARA BIOTHERAPEUTICS, INC.

Date:

May 12, 2026

By:

/s/ Yanina Grant-Huerta

Yanina Grant-Huerta

Chief Accounting Officer (Duly Authorized Officer and Principal Financial and Accounting Officer)

EX-99.1

Filename: atra-ex99_1.htm · Sequence: 2

EX-99.1

Exhibit 99.1

Atara Biotherapeutics Announces First Quarter 2026 Financial Results and Operational Progress

Productive meeting held with the FDA; planning for tabelecleucel BLA resubmission

Operating efficiencies and ATM proceeds extend cash runway into mid-2027

THOUSAND OAKS, Calif.--(BUSINESS WIRE)-- Atara Biotherapeutics, Inc. (Nasdaq: ATRA), a leader in T-cell immunotherapy, leveraging its novel allogeneic Epstein-Barr virus (EBV) T-cell platform to develop transformative therapies for patients with cancer and autoimmune diseases, today reported financial results for the first quarter 2026 and business updates.

Tabelecleucel (tab-cel® or Ebvallo™) for Post-Transplant Lymphoproliferative Disease (PTLD)

As previously communicated, Pierre Fabre Pharmaceuticals (PFP), with Atara’s support, had a productive meeting with the FDA and discussed a potential path forward to resubmitting the tab-cel Biologics License Application (BLA). The FDA agreed that a single arm study using an appropriate historical control applicable to the trial population, conducted in a pre-specified manner, could serve as an adequate and well controlled study and provide safety and efficacy data in support of a marketing application of tab-cel for the proposed indication.

PFP has indicated they intend to submit an updated dataset with additional patients and longer follow-up from the pivotal Phase 3 single arm ALLELE study as well as supportive data, as a part of the resubmission plan being defined with the FDA. Atara anticipates providing a further regulatory update in the third quarter.

First Quarter 2026 Financial Results

•

Cash, cash equivalents and short-term investments as of March 31, 2026 totaled $8.4 million, as compared to $8.5 million as of December 31, 2025.

•

Net cash used in operating activities was $3.1 million for the first quarter 2026, as compared to $28.1 million in the same period in 2025.

•

Total revenues were $0.5 million for the first quarter 2026, as compared to $98.1 million for the same period in 2025. The prior‑year period reflects a one‑time acceleration of revenue recognized upon the transfer of tab‑cel manufacturing responsibilities to Pierre Fabre Laboratories on March 31, 2025. In the current period, commercialization revenue relates solely to ongoing regulatory activities.

•

Total costs and operating expenses include non-cash stock-based compensation, depreciation and amortization expenses of $0.8 million for the first quarter 2026, as compared to $6.0 million for the same period in 2025.

•

Research and development expenses were $0.2 million for the first quarter 2026, as compared to $27.4 million for the same period in 2025.

•

Research and development expenses also include $0.3 million of non-cash stock-based compensation expenses for the first quarter 2026, as compared to $1.6 million for the same period in 2025.

•

General and administrative expenses were $3.6 million for the first quarter 2026, as compared to $11.5 million for the same period in 2025.

•

General and administrative expenses include $0.5 million of non-cash stock-based compensation expenses for the first quarter 2026, as compared to $2.6 million for the same period in 2025.

•

Atara reported a net loss of $4.1 million, or ($0.29) basic and diluted loss per share, for the first quarter 2026, as compared to net income of $38.0 million, or $3.53 basic earnings per share and $3.50 diluted earnings per share, for the same period in 2025.

2026 Outlook and Cash Runway:

•

Operating expenses are expected to decline significantly year-over-year, reflecting the full-year benefit of cost-reduction initiatives implemented in 2025.

•

Atara expects its cash, cash equivalents, and short-term investments as of March 31, 2026, combined with $4.8 million of ATM proceeds after quarter end and operating efficiencies achieved in 2025, will be sufficient to fund planned operations into mid-2027.

About Atara Biotherapeutics, Inc.

Atara is harnessing the natural power of the immune system to develop off-the-shelf cell therapies for difficult-to-treat cancers and autoimmune conditions that can be rapidly delivered to patients from inventory. With cutting-edge science and differentiated approach, Atara is the first company in the world to receive regulatory approval of an allogeneic T-cell immunotherapy. Our advanced and versatile T-cell platform does not require T-cell receptor or HLA gene editing and forms the basis of a diverse portfolio of investigational therapies that target EBV, the root cause of certain diseases. Atara is headquartered in Southern California. For more information, visit atarabio.com and follow @Atarabio on X and LinkedIn.

Forward-Looking Statements

This press release contains or may imply "forward-looking statements" within the meaning of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934. For example, forward-looking statements include statements regarding: (1) the development, timing and progress of tab-cel, including

the timing of PFP’s resubmission, the potential characteristics and benefits of tab-cel, and the results of, and prospects for bringing tab-cel to U.S. patients with EBV+ PTLD, the global partnership with Pierre Fabre Medicament involving tab-cel, and the potential financial benefits to Atara as a result of the global partnership with Pierre Fabre Medicament, including the receipt, timing and amount of any payments to be received by Atara thereunder; and (2) Atara’s cash runway, receipt of potential milestone payments, and estimated reduction in operating expenses, including Atara’s ability to fund its planned operations into mid-2027. Because such statements deal with future events and are based on Atara’s current expectations, they are subject to various risks and uncertainties and actual results, performance or achievements of Atara could differ materially from those described in or implied by the statements in this press release. These forward-looking statements are subject to risks and uncertainties, including, without limitation, risks and uncertainties associated with the costly and time-consuming pharmaceutical product development process and the uncertainty of clinical success; risks related to FDA’s review of tab-cel, including the risk that a resubmission of the tab-cel BLA may not address the deficiencies identified in the Complete Response Letter received on January 9, 2026 or other issues that may be raised by the FDA on review; the fact that PFP, and not Atara, holds the tab-cel BLA and controls the timing, content and strategy of any resubmission and related FDA interactions, and Atara's ability to influence the resubmission process is limited; our ability to access capital, and the sufficiency of Atara’s cash resources and access to additional capital on favorable terms or at all; and other risks and uncertainties affecting Atara, including those discussed in Atara’s filings with the Securities and Exchange Commission, including in the “Risk Factors” and “Management’s Discussion and Analysis of Financial Condition and Results of Operations” sections of Atara’s most recently filed periodic reports on Form 10-K and Form 10-Q and subsequent filings and in the documents incorporated by reference therein. Except as otherwise required by law, Atara disclaims any intention or obligation to update or revise any forward-looking statements, which speak only as of the date hereof, whether as a result of new information, future events or circumstances or otherwise.

Financials

Atara Biotherapeutics, Inc.

Condensed Consolidated Balance Sheets

(Unaudited)

(In thousands)

March 31,

December 31,

2026

2025

Assets

Current assets:

Cash and cash equivalents

8,360

8,482

Accounts receivable

—

1,253

Other current assets

3,813

2,477

Total current assets

12,173

12,212

Property and equipment, net

Operating lease assets

6,879

7,064

Other assets

890

886

Total assets

19,997

20,235

Liabilities and stockholders’ equity (deficit)

Current liabilities:

Accounts payable

637

127

Accrued compensation

629

1,271

Accrued research and development expenses

Deferred revenue

684

716

Liability related to the sale of future revenues – current portion

715

9,750

Other current liabilities

2,939

2,976

Total current liabilities

5,645

14,922

Operating lease liabilities – long-term

9,076

9,347

Liability related to the sale of future revenues – long-term

40,759

32,673

Other long-term liabilities

1,829

1,795

Total liabilities

57,309

58,737

Commitments and contingencies (Note 9)

Stockholders’ equity (deficit):

Common stock—$0.0001 par value, 500,000 shares authorized as of March 31, 2026 and December 31, 2025; 8,512 and 7,324 shares issued and outstanding as of March 31, 2026 and December 31, 2025, respectively

Additional paid-in capital

1,988,697

1,983,361

Accumulated other comprehensive income (loss)

—

Accumulated deficit

(2,026,010

)

(2,021,865

)

Total stockholders’ equity (deficit)

(37,312

)

(38,502

)

Total liabilities and stockholders’ equity (deficit)

19,997

20,235

Atara Biotherapeutics, Inc.

Condensed Consolidated Statements of Operations and Comprehensive Loss

(Unaudited)

(In thousands, except per share amounts)

Three Months Ended March 31,

2026

2025

Commercialization revenue

516

98,149

Costs and operating expenses:

Cost of commercialization revenue

124

20,439

Research and development expenses

164

27,433

General and administrative expenses

3,597

11,475

Total costs and operating expenses

3,885

59,347

Income (loss) from operations

(3,369

)

38,802

Other income (expense), net:

Interest income

236

Interest expense

(830

)

(1,017

)

Other income (expense), net

—

(11

)

Total other income (expense), net

(776

)

(792

)

Income (loss) before provision for (benefit from) income taxes

(4,145

)

38,010

Provision for (benefit from) income taxes

—

Net income (loss)

(4,145

)

38,010

Other comprehensive gain (loss):

Unrealized gain (loss) on available-for-sale securities

)

Comprehensive income (loss)

(4,146

)

38,002

Basic (loss) earnings per common share

(0.29

)

3.53

Diluted (loss) earnings per common share

(0.29

)

3.50

Basic and diluted weighted-average shares outstanding

14,081

10,764

Diluted weighted-average shares outstanding

14,081

10,851

Investor and Media Relations

Amber Daugherty

Sr. Director, Strategy and Operations

adaugherty@atarabio.com

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