Atara Biotherapeutics Inc. (NASDAQ:ATRA) stock plummeted on Monday, with a session volume of 2.75 million compared to the average volume of 92,283 as per data from Benzinga Pro.
The U.S. Food and Drug Administration (FDA) on Monday rejected the cell therapy company’s Biologics License Application (BLA) seeking approval for EBVALLO (tabelecleucel) for a serious complication after organ transplant.
The FDA issued a Complete Response Letter (CRL) for EBVALLO for adult and pediatric patients two years of age and older with Epstein-Barr virus-positive post-transplant lymphoproliferative disease (EBV+ PTLD), who have received at least one prior therapy.
EBV+ PTLD is a serious complication after organ or stem cell transplants, characterized by uncontrolled B-cell growth driven by EBV due to the necessary immunosuppression.
The CRL indicates that the FDA is unable to approve the EBVALLO BLA in its present form.
The BLA was resubmitted in 2025 after reaching alignment with the FDA on the acceptability of the resubmission criteria and fulfillment of the conditions as identified in the first Complete Response Letter in January 2025.
As previously disclosed, in the First CRL, the FDA identified a single deficiency regarding Good Manufacturing Practice (GMP) compliance and did not raise any concerns with respect to the safety, efficacy, or trial design.
In the current CRL, the FDA confirmed that the GMP compliance issues had been satisfactorily resolved, and no safety issues were raised.
However, in a complete reversal of position by the FDA, the CRL claims that the single-arm ALLELE trial, which the FDA previously confirmed as adequate to support the BLA filing, is no longer considered to be adequate to provide evidence of effectiveness for accelerated approval.
The FDA stated that the trial’s interpretability is confounded due to the trial’s study design, conduct, and analysis.
The FDA’s new position is contrary to its prior guidance to Atara, the FDA’s alignment with Atara on the clinical trial data set, and the acceptance of the trial design as a single-arm study as relevant for this patient population at BLA submission.
In November 2025, Atara transferred the BLA to Pierre Fabre Pharmaceuticals Inc., the U.S. pharmaceutical subsidiary of Pierre Fabre Laboratories.
As a first step towards resolution, Pierre Fabre intends to request a Type A meeting and expects it to be granted within 45 days.
Pierre Fabre and Atara plan to urgently interact with the FDA to find a path forward for the timely accelerated approval of EBVALLO.
Corporate and Financial Updates
In December 2025, Atara amended the commercialization agreement with Pierre Fabre Medicament to mitigate the impact of the cost of rebuilding commercial inventory in the U.S.
Atara agreed to reduce the milestone payment due upon BLA approval to $31 million in exchange for the right to receive an additional $15 million potential milestone payment.
Cash, cash equivalents, and short-term investments as of December 31, 2025, totaled approximately $8.5 million.
In 2025, Atara implemented an approximately 90% reduction in headcount and transitioned all tab-cel activities and associated costs to Pierre Fabre Laboratories.
ATRA Price Action: Atara Biotherapeutics shares were down 52.74% at $6.46 at the time of publication on Monday, according to Benzinga Pro data.
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