The FDA issued another rejection of Atara Biotherapeutics’ tabelecleucel (tab-cel), a T cell therapy for Epstein-Barr virus (EBV)-related complications after transplantation. The agency’s decision marks a further regulatory setback for the company’s late-stage cell therapy program and leaves the therapy without approval for a rare but serious transplant complication. Atara and partner Pierre Fabre had sought approval based on available efficacy and safety data; the FDA requested additional information or data to address outstanding concerns. The ruling underscores regulatory scrutiny of adoptive cell therapies and the evidentiary expectations for durable benefit and manufacturing controls.