FDA staff question data adequacy for Replimune's experimental skin cancer therapy

Regulators at the Food and Drug Administration have reiterated that Replimune lacks sufficient data to justify clearance of its investigational skin cancer drug RP1. The agency's briefing documents, issued before a forthcoming advisory committee meeting, criticize the company's single-arm trial, which combined RP1 with the PD-1 inhibitor Opdivo in patients whose cancers no longer responded to prior PD-1 therapy. FDA staff contend the design cannot adequately assess RP1's standalone efficacy or any systemic advantages of the locally injected treatment.

Replimune counters that randomizing patients to receive a placebo alongside PD-1 inhibitors would be neither feasible nor ethical, citing an absence of evidence that continued PD-1 monotherapy benefits this population. The dispute highlights the regulatory hurdles facing novel oncology combinations that rely on limited trial formats.