REPL Stock Lost 19% Of Its Value Today – Why Did The FDA Refuse Approval For Its Experimental Melanoma Drug?

• The FDA previously rejected approval for RP1 in July. 
• The agency noted that the members of the team who reviewed the resubmission were different from those who reviewed the initial application to maintain objectivity.
• Replimune can either resubmit or withdraw its application within a year.

Shares of Replimune Group Inc. (REPL) slumped 19% on Friday after the U.S. Food and Drug Administration refused approval for the company’s melanoma drug RP1.

The agency said in a letter to the company that the data submitted by Replimune as part of its application seeking approval of the drug is “insufficient to conclude substantial evidence of effectiveness” in the treatment of unresectable advanced cutaneous melanoma.

Previous Rejection

In late July 2025, the FDA had issued a complete response letter regarding the application for RP1 in combination with Nivolumab for the treatment of advanced melanoma.

The agency said in the letter then that it is unable to approve the application in its present form, and indicated that the trial conducted by the company for the drug is not considered to be an adequate and well-controlled clinical investigation that provides substantial evidence of effectiveness. It further urged that the company conduct and provide the results from a fresh trial for further consideration.

Replimune subsequently resubmitted its application in October with additional information and analyses but no additional trial.

On Friday, the FDA said that the revised application does not alter its initial conclusion of the ineffectiveness of the trials conducted by the company. The agency also noted that the members of the team who reviewed the resubmission were different from those who reviewed the initial application to maintain objectivity.

Replimune can either resubmit or withdraw its application within a year.

How Did Retail Traders React?

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

A Stocktwits user said that a new trial will not be easy on the company.

REPL stock is down 31% over the past 12 months. 

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