FDA Rejects Replimune’s Treatment for Advanced Melanoma

WOBURN, Mass., July 22, 2025 (GLOBE NEWSWIRE) — The U.S. Food and Drug Administration (FDA) has rejected a viral-based treatment from Replimune Group, Inc. for advanced melanoma, indicating a challenging regulatory landscape for the biotech company.

The FDA issued a Complete Response Letter (CRL) concerning Replimune’s Biologics License Application (BLA) for RP1, a treatment intended to work in combination with nivolumab. The agency cited that the clinical trial data, particularly from the IGNYTE trial, was inadequate to support effectiveness claims due to patient population heterogeneity.

In a statement, Replimune expressed disappointment, highlighting that the FDA did not raise these issues during earlier reviews. “We are surprised by this FDA decision and disappointed for advanced melanoma patients who have limited treatment options,” said Replimune CEO Sushil Patel.

Despite this rejection, the FDA did not identify any safety concerns regarding RP1. The company plans to request a Type A meeting with the FDA within 30 days to discuss potential pathways for an accelerated approval.

This setback poses a significant challenge, as Replimune noted that without timely approval, further development of RP1 for patients with limited treatment options might not be viable. RP1 is designed to harness genetically modified viruses to target and destroy tumors.

The company emphasizes that they still believe in RP1’s potential to offer substantial benefit to melanoma patients, despite this regulatory hurdle.