The trouble began on July 28, 2026, when the U.S. Food and Drug Administration released briefing documents regarding the company's application for accelerated approval. Regulators specifically flagged the response assessment methods utilized in the Phase 1/2 IGNYTE study, noting that the data provided for RP1—tested in combination with Bristol Myers Squibb’s Opdivo—confounded efficacy interpretations. The agency stated these irregularities hindered its ability to verify reported results for patients with advanced cutaneous melanoma.

Following the regulatory disclosure, Replimune shares plummeted by $3.28, closing at $5.35. Pomerantz LLP, a firm specializing in securities class actions, is now soliciting contact from shareholders to determine if the company’s leadership misled investors regarding the drug's development or violated fiduciary duties. The firm is currently reviewing potential claims of corporate misconduct related to the clinical trial disclosures.