Portnoy Law Firm Announces Class Action on Behalf of Atara Biotherapeutics, Inc. Investors
LOS ANGELES, March 25, 2026 (GLOBE NEWSWIRE) -- The Portnoy Law Firm advises Atara Biotherapeutics, Inc., (“Atara” or the "Company") (NASDAQ: ATRA) investors of a class action on behalf of investors that bought securities between May 20, 2024 and January 9, 2026, inclusive (the “Class Period”). Atara investors have until May 22, 2026 to file a lead plaintiff motion.
Investors are encouraged to contact attorney Lesley F. Portnoy, by phone 310-692-8883 or email: lesley@portnoylaw.com, to discuss their legal rights, or join the case via https://portnoylaw.com/atara-biotherapeutics-inc. The Portnoy Law Firm can provide a complimentary case evaluation and discuss investors’ options for pursuing claims to recover their losses.
The lawsuit alleges 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; and (iv) all the foregoing was likely to have a significant negative impact on Atara's business and financial condition.
On January 16, 2025, Atara issued a press release announcing its receipt of a Complete Response Letter (“CRL”) 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, the price of Atara shares declined by $5.33 per share, or approximately 40.5%, from $13.16 per share on January 15, 2025 to close at $7.83 on January 16, 2025.
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, the price of Atara shares declined by $0.52 per share, or approximately 8%, from $6.57 per share on January 17, 2025 to close at $6.05 on January 21, 2025.
On January 12, 2026, 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, the price of Atara shares declined by $7.79 per share, or approximately 57%, from $13.67 per share on January 9, 2026 to close at $5.88 on January 12, 2026.
The Portnoy Law Firm represents investors in pursuing claims caused by corporate wrongdoing. The Firm’s founding partner has recovered over $5.5 billion for aggrieved investors. Attorney advertising. Prior results do not guarantee similar outcomes.
Lesley F. Portnoy, Esq.
Admitted CA, NY and TX Bar
lesley@portnoylaw.com
310-692-8883
www.portnoylaw.com
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