Replimune Group, Inc. ( REPL ) stock plunged on Tuesday after a U.S. Food and Drug Administration (FDA) update.

The clinical stage biotechnology company received an FDA Complete Response Letter (CRL) regarding the Biologics License Application (BLA) for RP1 (vusolimogene oderparepvec) in combination with Bristol-Myers Squibb ( BMY ) Co.’s Opdivo (nivolumab) for advanced melanoma.

The CRL indicates that the FDA cannot approve the application in its present form.

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The FDA has indicated that the IGNYTE trial is not considered to be an adequate and well-controlled clinical investigation that provides substantial evidence of effectiveness.

Furthermore, the FDA said the trial cannot be adequately interpreted due to the heterogeneity of the patient population.

The CRL also states that items related to the confirmatory trial study design, including the contribution of components, need to be addressed. No safety issues were raised.

The company will request a Type A meeting and expects it to be granted within 30 days.

Replimune ( REPL ) plans to urgently interact with the FDA to find a path forward for the timely accelerated approval of RP1, without which the development of RP1 for advanced cancer patients with limited options will not be viable.

“We are surprised by this FDA decision and disappointed…,” said Sushil Patel, Ph.D., Chief Executive Officer, Replimune ( REPL ). “The issues highlighted in the CRL were not raised by the agency during the mid- and late-cycle reviews. Additionally, we had also aligned on the design of the confirmatory study. We strongly believe that RP1 combined with nivolumab can substantially benefit advanced melanoma patients.”

Replimune ( REPL ) presented two posters highlighting data updates for RP1 at the 2025 American Society of Clinical Oncology Annual Meeting in June.

The poster included an analysis from the IGNYTE clinical trial of RP1 plus nivolumab in the cohort of anti-PD-1 failed melanoma patients (n=140).

In the trial, the objective response rate (ORR) was 32.9%. The complete response rate was 15.0% and landmark overall survival (OS) rates at 1, 2, and 3 years were 75.3%, 63.3%, and 54.8% respectively. The median OS has not been reached.

RP1 injections directly into the lung and liver were generally well tolerated, resulting in few organ-specific adverse events that were easily managed.

No bleeding events were reported after liver injection. RP1 was assessed in various patient samples, demonstrating that RP1 DNA is primarily detected at the injection site, consistent with RP1 replication in the tumor, and much more rarely on dressings, in blood, on mucous membranes, or in urine.

Price Action: REPL stock is down 74.80% at $3.11 at the last check Tuesday.

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