FDA Staff Signal Replimune RP1 Melanoma Trial Failure, Slashing Stock

FDA staff reports find that Replimune's RP1 melanoma therapy lacks sufficient evidence of benefit, linked to flaws in the IGNYTE trial design and response assessment criteria.

The agency concludes that the single-arm IGNYTE study data cannot reliably show whether RP1 contributes to the observed effect, especially versus nivolumab alone.

Repeated FDA rejections and negative advisory‑committee‑oriented briefing documents have driven Replimune stock down sharply, with drops of roughly 60–75% over the past year.

Regulatory documents emphasize that the study is not an adequate and well‑controlled clinical investigation, and that the efficacy results are not of sufficient magnitude to support approval.

Replimune has responded with additional analyses and discussions with the FDA but has not yet established a clear path forward under the accelerated‑approval pathway.

Investors have reacted with heavy selling, pushing shares to all‑time lows and prompting management to consider layoffs and cost cuts.

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