Replimune Investors Face Losses After FDA Rejection Triggers Lawsuit

The litigation targets the period between October 20, 2025, and April 10, 2026, when Replimune reported that the FDA had accepted its resubmitted Biologics License Application. According to the complaint, company leadership failed to address critical concerns regarding study design and relied on preliminary data from a small, 40-patient analysis—just 10% of the planned enrollment—to support its application.

The regulatory setback became public on April 10, 2026, when the FDA issued a Complete Response Letter detailing significant deficiencies in the IGNYTE and IGNYTE-3 clinical trials. The agency noted that Replimune had ignored repeated warnings regarding the study structure, rendering the results insufficient to prove the effectiveness of RP1. Following the disclosure, Replimune’s stock cratered, falling nearly 20% on the day of the announcement and plummeting another 64% by April 13, 2026.

Investors who incurred losses during this window have until October 5, 2026, to file for lead plaintiff status. Robbins LLP, which is handling the case on a contingency basis, argues that the company’s optimistic public disclosures lacked a reasonable basis and obscured the reality of the ongoing regulatory impasse.