Atara Biotherapeutics and Pierre Fabre Pharmaceuticals said they are resubmitting Ebvallo (tabelecleucel) to the FDA after the agency delivered additional rejection signals. The therapy targets Epstein-Barr virus-positive post-transplant lymphoproliferative disease (EBV+ PTLD), a rare but potentially fatal complication in transplant recipients. The companies previously received a complete response letter tied to manufacturing and later disputed the adequacy of the single-arm Phase 3 ALLELE study for a BLA. In the new submission, the partners say they have incorporated additional data intended to align the clinical dataset and regulatory expectations. Analysts cited a likely Class 2 BLA resubmission pathway, suggesting a potential target action date in late March 2027. For the sector, the case underlines how quickly cell-therapy development timelines can bend when FDA guidance shifts after leadership transitions—especially for complex manufacturing and interpretability issues.