Key TakeawaysFDA delivered a second complete response letter rejecting Replimune’s RP1 advanced melanoma treatmentThe therapy was under review for use with Bristol Myers Squibb’s (BMY) Opdivo immunotherapyRegulatory concerns centered on trial design being deemed insufficient and poorly controlledShares of REPL plummeted approximately 19% to $4.76, with trading suspended twice due to extreme volatilityCurrent trading levels represent a significant decline from the 52-week peak of $13.24Replimune (REPL) has encountered its second regulatory roadblock from the FDA, as the agency maintains its position regarding fundamental flaws in the clinical trial methodology supporting the drug application.Replimune Group, Inc., REPLThe regulatory agency delivered a complete response letter rejecting approval for RP1, scientifically designated as vusolimogene oderparepvec, for combination therapy with Bristol Myers Squibb’s (BMY) Opdivo in treating advanced melanoma patients who had undergone prior anti-PD-1 therapy.In correspondence directed to Kari Jeschke, Replimune’s senior vice president of regulatory affairs, the FDA stated that supplementary exploratory data analyses failed to change its previous determination. The agency concluded that the RPL-001-16 clinical study did not meet standards as an adequate and well-controlled investigation.No safety issues were identified by the FDA — the problem lies entirely with insufficient efficacy data.This marks the second time the application has been turned down. The initial rejection occurred in July 2025, following Vinay Prasad’s appointment as head of the FDA’s Center for Biologics Evaluation and Research by two months. After resubmitting its Biologics License Application, Replimune received acceptance for review in October 2025.REPL shares tumbled roughly 19% to reach $4.76 following the announcement. Two trading halts occurred throughout the session as volatility protections kicked in. Based on Dow Jones Market Data, this decline positions the stock toward its weakest closing level since October.At current pricing, REPL remains substantially beneath its 52-week peak of $13.24.Understanding RP1RP1 represents a genetically modified variant of Herpes Simplex Virus type 1 — the viral strain responsible for cold sores. Replimune engineered the virus to reproduce exclusively within cancerous tumor cells, destroying them while simultaneously activating enhanced immune system responses from white blood cells.This represents the flagship candidate within Replimune’s RPx development platform, which concentrates on oncolytic immunotherapy approaches for solid tumor cancers.The biotechnology company currently maintains a market capitalization of approximately $393 million. With negative earnings typical of clinical-stage biotech companies developing their product pipelines, no P/E ratio is applicable.Internal Trading and Company FinancesReplimune holds a GF Score of 40 out of 100, with profitability metrics rating only 1 out of 10. The company’s financial strength assessment stands at 6 out of 10.During the last three-month period, company insiders disposed of $0.1 million in shares, while no insider purchases were documented.Shares currently trade at $4.76, representing a substantial discount from the $13.24 52-week high reached earlier this year.The post Replimune (REPL) Shares Plunge 19% as FDA Issues Second Rejection for Melanoma Treatment appeared first on Blockonomi.