Replimmune Group Inc. (NASDAQ:REPL) stock is trading lower on Tuesday after the U.S. Food and Drug Administration released briefing documents related to the company’s vusolimogene oderparepvec, or RP1, for skin cancer.
The company is seeking accelerated approval for RP1 in combination with Bristol-Myers Squibb Co. (NYSE:BMY) Opdivo (nivolumab) for advanced melanoma.
• Replimune Group stock is among today’s weakest performers. What’s pressuring REPL stock?
FDA Says Mid-Stage Study Is ‘Not Interpretable’
The FDA has deemed the single-arm mid-stage study submitted by Replimune to support the approval of the drug as “not interpretable.”
In April, the FDA rejected the company’s application for RP1 in combination with nivolumab for advanced melanoma, challenging the agency’s assessment of its data package.
In June 2025, the FDA issued a Complete Response Letter for RP1, indicating that the IGNYTE trial is not considered to be an adequate and well-controlled clinical investigation that provides substantial evidence of effectiveness.
The agency accepted resubmission in June with a decision date of Aug. 2 — but also announced a meeting of the Cellular, Tissue, and Gene Therapies Advisory Committee on July 30 to discuss the therapy.
FDA Raises Concerns Over Efficacy Assessment
The document highlighted the response assessment used in the Phase 1/2 IGNYTE study “confounds interpretation of the reported efficacy results and limits FDA’s ability to verify the reported results.”
The FDA staff also noted that the objective response data from the single-arm trial “are not of sufficient magnitude to overcome concerns about the contribution of effect,” without a reliable historical control, the FDA stated “it cannot be determined whether RP1 contributes to any observed effect” when combined with Opdivo.
“The overall survival analysis from the single-arm IGNYTE study is not interpretable,” the FDA wrote.
Replimune Continues To Defend RP1 Data
In April, the company argued that the dataset supporting its breakthrough therapy designation should have been sufficient for accelerated approval, pointing to results from the IGNYTE trial.
In that study, patients who had progressed on prior anti-PD-1 therapies showed a 34% response rate when treated with RP1 plus nivolumab, with a median duration of response of 24.8 months and a favorable safety profile.
REPL Stock Price Activity: Replimune Group shares were down 33.78% at $5.72 at the time of publication on Tuesday, according to Benzinga Pro data.
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