Regeneron Pharmaceuticals IncSecurities class action lawsuit alleging misleading disclosures about trial data, causing stock drop.

A securities class action has been filed against Regeneron Pharmaceuticals on behalf of shareholders who purchased stock between August 1, 2025 and May 15, 2026, with a lead plaintiff deadline of September 14, 2026. The complaint alleges the company and certain executives minimized the significance of a prolonged slowdown in progression-free survival event accrual in the Phase III Fianlimab-Libtayo Study. On April 29, 2026, Regeneron disclosed that the primary analysis would consider all enrolled patients with at least six months of follow-up, prompting analyst reactions that questioned the study's statistical assumptions and endpoint timing. Shares fell from a class period high of $731.77 to $629.68, a decline of $102.09 per share or 13.95 percent. The lawsuit claims these disclosures and the subsequent announcement that the trial did not reach statistical significance for its primary endpoint caused investor losses.
Regeneron Pharmaceuticals IncSecurities class action lawsuit alleging misleading disclosures about trial data, causing stock drop.