The lawsuit, filed in the District of Massachusetts, claims Replimune and its top executives violated the Securities Exchange Act of 1934 by failing to disclose critical deficiencies in the clinical study designs for RP1. While the company announced in October 2025 that the FDA had accepted its resubmitted Biologics License Application, the complaint alleges that leadership ignored recurring agency warnings about the study protocols. Specifically, the firm reportedly submitted data from an unplanned analysis involving only 40 patients—just 10% of the originally planned enrollment—which the FDA later cited as insufficient to support approval.

When the FDA issued a Complete Response Letter on April 10, 2026, rejecting the application, the agency stated that the company’s data failed to meet evidentiary standards for effectiveness. The market reaction was severe: Replimune’s stock price plummeted more than 19% upon the initial news of the rejection, and fell an additional 64% after the company acknowledged the FDA’s preference for a randomized controlled trial. Investors seeking to participate in the litigation, led by Robbins Geller Rudman & Dowd LLP, are encouraged to contact the firm before the October deadline to represent the class in court.