Replimune Group's Melanoma Treatment Approval Uncertain Amid FDA Scrutiny

Replimune Group (REPL) shares fell 39.4% after the FDA's complete response letter for its melanoma treatment candidate, RP1, raised uncertainty about approval. The company met with the FDA to discuss the biologics license application, but the FDA provided feedback that cannot be interpreted as a clear path forward for RP1. Replimune remains committed to working with the FDA to determine an expeditious path forward.

Replimune Group Inc. (REPL) shares fell 39.4% on September 12, 2025, following a Type A meeting with the FDA that failed to provide a clear regulatory pathway for its melanoma treatment candidate, RP1. The meeting, held on September 16, discussed the complete response letter (CRL) issued by the FDA on July 22, 2025, regarding Replimune's biologics license application (BLA) for RP1 in combination with nivolumab (Opdivo) for treating advanced melanoma.

The FDA expressed concerns about the adequacy of the phase 1/2 IGNYTE trial (NCT03767348) to support the approval of the combination. The CRL noted that the trial's patient population was heterogeneous and that the FDA could not adequately interpret the findings. Additionally, the CRL outlined action items for Replimune related to the design of the confirmatory trial FDA Grants Type A Meeting to Discuss RP1 Plus Nivolumab in Advanced Melanoma^[1].

Despite the setback, Replimune remains committed to working with the FDA to determine an expeditious path forward for RP1. The company's CEO, Sushil Patel, emphasized the unmet need in advanced melanoma and the "compelling risk-benefit profile of RP1 observed in the IGNYTE trial." Patel stated that the company is evaluating the FDA’s feedback to determine next steps for RP1 Replimune stock plunges after FDA meeting fails to clear path forward^[2].

The negative market reaction reflects investor concerns about potential delays in bringing RP1 to market following the regulatory hurdle. Replimune's stock, which had been trading around $10 per share before the meeting, fell to $5.64, a 41.7% decrease.