Replimune announced a favorable outcome for its melanoma drug following a meeting of the FDA’s Cellular, Tissue and Gene Therapies Advisory Committee.

  • The panel voted 10-3 that the results from a key clinical study of the company’s therapy, known as RP1, were both reliable and clinically meaningful for certain patients with advanced melanoma. 
  • RP1 faced two prior FDA rejections.
  • The FDA’s new decision on the therapy is expected by August 2.

Replimune Group, Inc. (REPL) said on Thursday that an independent panel of experts advising the U.S. Food and Drug Administration voted in favor of its experimental treatment for advanced melanoma.

The Massachusetts-based biotechnology company announced the favorable outcome following a meeting of the FDA’s Cellular, Tissue, and Gene Therapies Advisory Committee. The panel voted 10-3 that the results from a key clinical study of the company’s therapy, known as RP1, were both reliable and clinically meaningful for patients with advanced melanoma who had already progressed on prior anti-PD-1 therapy.

Shares of the company soared 127% after hours following the meeting. 

How Did The Committee Decide?

Melanoma is a serious form of skin cancer that can spread aggressively. While checkpoint inhibitor drugs that target the PD-1 protein have transformed care for many patients in recent years, a significant number eventually see their disease return or worsen. Options remain limited for this group, creating a clear unmet medical need.

RP1 is an experimental treatment that uses a modified virus designed to attack tumor cells directly while helping the body’s immune system recognize and fight the cancer more effectively. In the study under review, it was given together with nivolumab, an already approved immunotherapy drug.

Committee members discussed whether the single-arm trial design provided a trustworthy picture of how well the combination works and how long responses last. Despite some questions about the study’s approach, the majority found the results convincing enough to support the therapy’s potential value.

“We are encouraged by today’s outcome,” said Sushil Patel, Replimune’s chief executive. He said the company looks forward to continuing work with the FDA.

The agency’s decision on the therapy is expected by August 2. A larger confirmatory trial is already underway.

Replimune’s Prior Rejections

RP1 faced two prior FDA rejections. In July 2025, the agency refused to approve the drug, saying the main supporting study (IGNYTE) was not an adequate and well-controlled trial that provided solid proof of effectiveness. Regulators pointed to the mixed patient population and challenges in isolating RP1’s specific contribution when combined with nivolumab.

After Replimune resubmitted additional data, the FDA issued a second rejection on April 10, again finding the evidence insufficient to show substantial effectiveness.

How Did REPL Retail Traders React?

On Stocktwits, retail sentiment around REPL stock stayed within ‘extremely bullish’ territory over the past 24 hours, while message volume remained ‘extremely high.’

A Stocktwits user cheered the positive vote at the meeting.

Another user opined that the concerns raised by the FDA during previous rejections remain unaddressed.

REPL Stock has fallen 44% year-to-date. 

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