Robbins LLP has filed a securities class action on behalf of investors who purchased Regeneron Pharmaceuticals securities between August 1, 2025 and May 15, 2026. The lawsuit alleges Regeneron misled investors about the viability of its Phase 3 Fianlimab-Libtayo clinical trial for advanced melanoma, failing to disclose that the study's statistical assumptions were flawed, the treatment arm was not meaningfully differentiating from standard therapies, and the trial was unlikely to meet its primary endpoint. Regeneron's stock fell approximately 6.2% on April 29, 2026 after the company disclosed modifications to expand the patient analysis, and declined another 9.8% following the May 15, 2026 announcement that the trial did not achieve statistical significance for progression-free survival. Investors who suffered losses have until September 14, 2026 to seek appointment as lead plaintiff.
Regeneron Pharmaceuticals IncSecurities class action lawsuit alleging misleading disclosures about clinical trial viability.