NEW YORK, March 24, 2026 (GLOBE NEWSWIRE) -- Pomerantz LLP announces that a class action lawsuit has been filed against Atara Biotherapeutics, Inc. (“Atara” or the “Company”) (NASDAQ: ATRA) and certain officers.   The class action, filed in the United States District Court for the Central District of California, and docketed under 26-cv-03083, is on behalf of a class consisting of all persons and entities other than Defendants that purchased or otherwise acquired Atara securities between May 20, 2024 and January 9, 2026, both dates inclusive (the “Class Period”), seeking to recover damages caused by Defendants’ violations of the federal securities laws and to pursue remedies under Sections 10(b) and 20(a) of the Securities Exchange Act of 1934 and Rule 10b-5 promulgated thereunder, against the Company and certain of its top officials.

If you are an investor who purchased or otherwise acquired Atara securities during the Class Period, you have until May 22, 2026, to ask the Court to appoint you as Lead Plaintiff for the class.  A copy of the Complaint can be obtained at www.pomerantzlaw.com.  To discuss this action, contact Danielle Peyton at newaction@pomlaw.com or 646-581-9980 (or 888.4-POMLAW), toll-free, Ext. 7980. Those who inquire by e-mail are encouraged to include their mailing address, telephone number, and the number of shares purchased.  

[Click here for information about joining the class action]

Atara develops therapies for patients with solid tumors, hematologic cancers, and autoimmune diseases in the United States and the United Kingdom. The Company’s lead product candidate is tabelecleucel (also referred to as tab-cel or EBVALLO), a T-cell immunotherapy program for the treatment of, inter alia, Epstein-Barr virus positive post-transplant lymphoproliferative disease (“EBV+ PTLD”).

Atara is partnered with Pierre Fabre Médicament, a subsidiary of the Pierre Fabre Laboratories group (collectively, “Pierre Fabre”), for the commercialization of tabelecleucel.  The Company relies in significant part on milestone payments—i.e., financial payments conditioned upon Atara achieving specific developmental targets for tabelecleucel—by Pierre Fabre, to fund its operations, as well as certain of Pierre Fabre’s services to execute on its business activities, particularly those related to tabelecleucel’s potential regulatory approval. 

In May 2024, Atara announced its submission of a Biologics License Application (“BLA”) to the U.S. Food and Drug Administration (“FDA”) for tabelecleucel as a monotherapy for the treatment of adult and pediatric patients two years of age and older with EBV+ PTLD who have received at least one prior therapy (the “tabelecleucel BLA”).  The tabelecleucel BLA was purportedly supported by data from the Company’s Phase 3 ALLELE study evaluating tabelecleucel as a treatment for EBV+ PTLD.

The complaint alleges that, throughout the Class Period, Defendants made materially false and misleading statements regarding the Company’s business, operations, and prospects.  Specifically, Defendants made false and/or misleading statements and/or failed to disclose that: (i) certain manufacturing issues, as well as deficiencies inherent in the ALLELE study, made it unlikely that the FDA would approve the tabelecleucel BLA; (ii) accordingly, tabelecleucel’s regulatory prospects were overstated; (iii) the aforementioned manufacturing issues also subjected Atara to a heightened risk of regulatory scrutiny, as well as jeopardized its ongoing clinical trials; (iv) all the foregoing was likely to have a significant negative impact on Atara’s business and financial condition; and (v) as a result, Defendants’ public statements were materially false and/or misleading at all relevant times.

The truth began to emerge on January 16, 2025, when Atara issued a press release announcing its receipt of a Complete Response Letter (“CRL”)—i.e., an FDA notice that an application will not be approved in its present form—regarding the tabelecleucel BLA, stating that “[t]he CRL was solely related to observations as part of a standard pre-license inspection of a third-party manufacturing facility for EBVALLO.”

On this news, Atara’s stock price fell $5.33 per share, or 40.5%, to close at $7.83 per share on January 16, 2025.

Then, on January 21, 2025, Atara issued a press release announcing “that the [FDA] has placed a clinical hold on Atara’s active Investigational New Drug (IND) applications” due to “inadequately addressed GMP [good manufacturing practice] compliance issues identified during the pre-license inspection of the third-party manufacturing facility referenced in the [CRL]” issued in connection with the tabelecleucel BLA.

On this news, Atara’s stock price fell $0.52 per share, or 7.91%, to close at $6.05 per share on January 21, 2025.

The truth continued to emerge on January 12, 2026, when Atara issued a press release announcing that the FDA had issued another CRL regarding the tabelecleucel BLA—which the Company had resubmitted to the FDA in July 2025—stating that “[t]he CRL indicates that the FDA is unable to approve the EBVALLO™ BLA in its present form” because “the single arm ALLELE trial . . . is no longer considered to be adequate to provide evidence of effectiveness for accelerated approval” and “the trial’s interpretability is confounded due to trial study design, conduct, and analysis.”

On this news, Atara’s stock price fell $7.79 per share, or 56.99%, to close at $5.88 per share on January 12, 2026.

Pomerantz LLP, with offices in New York, Chicago, Los Angeles, London, Paris, and Tel Aviv, is acknowledged as one of the premier firms in the areas of corporate, securities, and antitrust class litigation. Founded by the late Abraham L. Pomerantz, known as the dean of the class action bar, Pomerantz pioneered the field of securities class actions. Today, more than 85 years later, Pomerantz continues in the tradition he established, fighting for the rights of the victims of securities fraud, breaches of fiduciary duty, and corporate misconduct. The Firm has recovered billions of dollars in damages awards on behalf of class members. See www.pomlaw.com. 

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CONTACT:
Danielle Peyton
Pomerantz LLP
dpeyton@pomlaw.com
646-581-9980 ext. 7980