The FDA’s Cellular, Tissue, and Gene Therapies Advisory Committee convened to review Replimune’s RP1, an engineered viral immunotherapy for melanoma, in a meeting tied to a possible path for accelerated approval. RP1 was previously rejected, and the company now faces scrutiny on whether its data sufficiently prove benefit for the drug itself. Multiple briefing-based reports and FDA staff concerns highlighted disputes over RP1’s single-arm evidence, including the adequacy of trial design and the handling of efficacy estimates versus the FDA’s interpretation. Investors reacted negatively to prior criticisms that RP1’s Ignyte trial did not demonstrate performance strong enough to support approval. The advisory meeting effectively puts a spotlight on how FDA leadership and career staff weigh accelerated-approval standards for complex immunotherapies and on how single-arm endpoint arguments land in real-time under regulator review.