Atara delays $9M payment, issues new warrant

Atara Biotherapeutics has amended its royalty purchase agreement with HealthCare Royalty (HCRx), pushing back a one-time $9.0 million milestone payment from June 30, 2026 to January 1, 2028.

Rhea-AI Filing Summary

Atara Biotherapeutics has amended its royalty purchase agreement with HealthCare Royalty (HCRx), pushing back a one-time $9.0 million milestone payment from June 30, 2026 to January 1, 2028. This later due date eases near-term cash obligations tied to its commercialization agreement with Pierre Fabre Medicament.

In return, Atara issued HCRx a warrant to purchase up to 400,000 shares of common stock at an exercise price of $0.0001 per share. The warrant is immediately exercisable, has no expiration date, and includes a 4.99% beneficial ownership cap, with the option for cashless exercise. Atara plans to register the resale of the underlying shares in a future registration statement.

Insights

Biotech credit & capital-structure analyst

Atara delays a $9M cash outflow by 18 months in exchange for a modest warrant grant.

The amendment moves a one-time $9.0 million milestone payment to HCRx from June 30, 2026 to January 1, 2028. This pushes a meaningful cash obligation further into the future, which can help a development-stage biotech preserve liquidity for R&D and regulatory work around tab-cel.

In consideration, Atara granted HCRx a warrant for up to 400,000 common shares at a nominal $0.0001 exercise price, immediately exercisable with no expiry and subject to a 4.99% beneficial ownership limit. The economic value of this warrant depends on Atara’s future share price and any subsequent resale registration, which the company intends to file under the warrant’s registration rights.

8-K Event Classification

3 items: 1.01, 3.02, 8.01

3 items

Item 1.01 Entry into a Material Definitive Agreement Business

The company signed a significant contract such as a merger agreement, credit facility, or major partnership.

Item 3.02 Unregistered Sales of Equity Securities Securities

The company sold equity securities in a private placement or other unregistered transaction.

Item 8.01 Other Events Other

Voluntary disclosure of events the company deems important to shareholders but not covered by other items.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What change did Atara Biotherapeutics (ATRA) make to its $9.0 million payment to HCRx?

Atara and HCRx agreed to delay a one-time $9.0 million milestone payment from June 30, 2026 to January 1, 2028. This amendment extends the timeline for Atara’s cash obligation under its commercialization agreement with Pierre Fabre Medicament.

Why did Atara Biotherapeutics issue a warrant in connection with the HCRx amendment?

In connection with the amendment, Atara issued HCRx a warrant for up to 400,000 shares of common stock at an exercise price of $0.0001 per share. This warrant appears to be consideration for postponing the $9.0 million cash payment date.

What are the key terms of the new Atara Biotherapeutics warrant to HCRx?

The warrant allows purchase of up to 400,000 common shares at $0.0001 per share, is immediately exercisable, and has no expiration date. Exercise is limited by a 4.99% beneficial ownership cap and may be done on a cashless basis.

Will Atara Biotherapeutics register the shares underlying the HCRx warrant?

Under the warrant’s terms, Atara intends to file a registration statement covering the resale of the common stock issuable upon exercise. This future registration would allow HCRx to resell warrant shares publicly, subject to the warrant’s registration rights provisions.

How does the HCRx amendment relate to Atara’s partnership with Pierre Fabre Medicament?

The $9.0 million payment is linked to a milestone in the Amended and Restated Commercialization Agreement with Pierre Fabre Medicament. Extending the payment due date to January 1, 2028 provides Atara and its partner more time as they work on regulatory pathways for tab-cel.

What additional disclosure did Atara Biotherapeutics provide with this 8-K filing?

Atara referenced a press release titled “Atara Biotherapeutics Provides a Business Update”. The release highlights the amended payment timing with HCRx, the new warrant, and management’s commentary on focusing resources on addressing concerns in the latest CRL and advancing tab-cel.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Accepted by SEC EDGAR 02/23/2026 - 08:29 AM Learn about SEC filing dates

false 0001604464 0001604464 2026-02-20 2026-02-20

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): February 20, 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 1.01 Entry into a Material Definitive Agreement.

On February 20, 2026, Atara Biotherapeutics, Inc., (the “Company”) entered into an Amendment (the “Amendment”) to the Purchase and Sale Agreement dated as of December 20, 2022 (the “Agreement”) with HCR Molag Fund, L.P. (“HCR”). Under the terms of the Amendment, HCR agreed to amend the due date of the one-time of $9.0 million cash payment associated with the achievement of a certain milestone within the Amended and Restated Commercialization Agreement dated October 31, 2023 with Pierre Fabre Medicament, as amended, from June 30, 2026 to January 1, 2028. In connection with the Amendment, the Company issued a warrant to purchase up to 400,000 shares of the Company’s Common Stock (the “Warrant”).

The exercise price of the Warrant is equal to $0.0001 per share, subject to adjustment as provided therein, and the Warrants will be exercisable immediately and has no expiration date. The holder will not have the right to exercise any portion of the Warrant if the holder (together with its affiliates) would beneficially own in excess of 4.99% of the number of shares of Common Stock outstanding immediately after giving effect to the exercise, as such percentage ownership is determined in accordance with the terms of the Warrants.

The Warrant may be exercised through a cashless exercise, in which the net number of shares of Common Stock to be issued is determined according to a formula set forth in the Warrant.

The foregoing is only a summary of the terms of the Amendment and the Warrant and does not purport to be complete and is qualified in its entirety by reference to the full text of: (i) the Amendment, a copy of which is filed herewith as Exhibit 10.1; and (ii) the Warrant, a copy of which is attached to this report as Exhibit 4.1.

Item 3.02 Unregistered Sales of Equity Securities.

The information contained in Item 1.01 of this Current Report is incorporated by reference into this Item 3.02. The Company issued the Warrant pursuant to the exemption from the registration requirements of the Securities Act of 1933, as amended (the “Securities Act”) available under Section 4(a)(2) of the Securities Act. Pursuant to the terms of the Warrant, the Company intends to file a registration statement relating to the resale of the Company’s Common Stock underlying the Warrant, subject to the registration rights provisions of the Warrant.

Item 8.01 Other Events.

On February 23, 2026, the Company issued a press release titled “Atara Biotherapeutics Provides a Business Update”. A copy of the press release is filed as Exhibit 99.1 and incorporated by reference into this Item 8.01.

Item 9.01 Financial Statements and Exhibits

(d) Exhibits.

Exhibit No.		Description
4.1		Form of Warrant
10.1		Amendment No. 1 to the Purchase and Sale Agreement, by and between Atara Biotherapeutics, Inc. and HCR Molag Fund L.P., dated as of February 20, 2026
99.1		Press Release dated February 23, 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: February 23, 2026				By:		/s/ AnhCo Thieu Nguyen
						AnhCo Thieu Nguyen President and Chief Executive Officer (Duly Authorized Officer and Principal Executive Officer)

Exhibit 99.1

Atara Biotherapeutics Provides a Business Update

Atara renegotiates one-time milestone payment with HCRx

THOUSAND OAKS, California —(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 announced that the Company entered into an amendment (the Amendment) to the Purchase and Sale Agreement dated as of December 20, 2022 with a fund managed by HealthCare Royalty (“HCRx”). Under the terms of the Amendment, HCRx agreed to amend the due date of the one-time of $9.0 million cash payment associated with the achievement of a certain milestone within the Amended and Restated Commercialization Agreement dated October 31, 2023, with Pierre Fabre Medicament, as amended, from June 30, 2026 to January 1, 2028.

“We are thankful for this extension to our one-time cash payment to HCRx”, said Cokey Nguyen, President and Chief Executive Officer of Atara. “This flexibility allows us to focus on addressing the concerns in the latest CRL with the agency, supporting our partners, Pierre Fabre. We believe in the potential of tabelecleucel and are optimistic about the path forward.”

In connection with the Amendment, the Company issued a warrant to purchase up to 400,000 shares of the Company’s Common Stock. The exercise price of the Warrant is equal to $0.0001 per share, subject to adjustment as provided therein, and the Warrant will be exercisable immediately and have no expiration date. The exercise of the Warrant is subject to a beneficial ownership limit as set forth in the Warrant.

“Tabelecleucel is proving to be an important option for European patients suffering from relapsed or refractory EBV+ PTLD, an ultra-rare and aggressive lymphoma”, said Clarke Futch, Chairman and Chief Executive Officer at HCRx. “This amendment to our agreement provides Atara and their partner time to work with the FDA for a path to approval in the United States, where there remain limited treatment options and significant unmet need.”

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 and (2) the timing of the $9.0 million cash payment to HCRx. 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 our year-end the costly and time-consuming pharmaceutical product development process and the uncertainty of clinical success; risks related to FDA’s review of tab-cel; 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 the Company’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.

Investor and Media Relations

Amber Daugherty

Sr. Director, Strategy and Operations

adaugherty@atarabio.com

Filing Exhibits & Attachments

6 documents

Press Releases

• EX-99.1 EX-99.1 7.7 KB

Agreements & Contracts

• EX-10.1 EX-10.1 26.6 KB

Other Documents

• EX-4.1 EX-4.1 71.4 KB
• EX-101 XBRL TAXONOMY EXTENSION SCHEMA 2.8 KB
• EX-101 XBRL TAXONOMY EXTENSION LABEL LINKBASE 16.8 KB
• EX-101 XBRL TAXONOMY EXTENSION PRESENTATION LINKBASE 10.6 KB