Pierre Fabre Pharmaceuticals revealed that a Biologic License Application (BLA) for Epstein-Barr virus (EBV) T-cell therapy tabelecleucel has been met with a Complete Response Letter (CRL) from the US FDA. The France-based firm is seeking approval for tabelecleucel as a treatment for EBV+ post-transplant lymphoproliferative disease (PTLD).
Pierre Fabre noted that the agency acknowledged resolution of prior manufacturing concerns but now does not view the single-arm ALLELE trial as adequate evidence of effectiveness—marking a reversal after more than five years of dialogue. The CRL blocks current approval and will require further regulatory engagement and potential additional studies before the therapy can move forward in the US.
Tabelecleucel (also called tab-cel or Ebvallo) is an allogeneic, off-the-shelf, EBV-specific T-cell immunotherapy designed to target and eliminate EBV-infected cells in patients with EBV+ PTLD. The drug was originated by Memorial Sloan-Kettering Cancer Center (MSKCC) and licensed to Atara Biotherapeutics, who turned to Pierre Fabre for support on commercialization under a 2021 partnership. The program is now under Pierre Fabre’s global clinical stewardship following a transfer from Atara in November 2025.
The CRL is tabelecleucel’s second in the space of 12 months after the FDA issued a first CRL in January 2025, pointing to issues with a pre-license inspection of a third-party manufacturing facility but raising no concerns regarding the trial’s design in relation to demonstrating efficacy. Atara refiled the BLA in July 2025, supported by data from more than 430 treated patients from the pivotal ALLELE study. Tabelecleucel was first approved in Europe in 2022 for the EBV+ PTLD indication, while there are currently no FDA-approved treatments for affected patients in the United States.
Pierre Fabre’s statement raised concerns regarding the implications of the FDA’s decision for the development of rare and ultra-rare diseases. The French firm plans to seek an “urgent meeting” with FDA regulators, together with Atara, to pursue a viable path to accelerated approval while continuing expanded access to the therapy for patients in need.