Regeneron Pharmaceuticals Investigation Initiated: Levi & Korsinsky Investigates the Officers and Directors of Regeneron Pharmaceuticals (REGN)

Regeneron's executives were optimistic about the potential for fianlimab + Libtayo; when the study failed to produce exepected results, the stock opened down more than 10%. NEW YORK, May 18, 2026 /PRNewswire/ -- Regeneron Pharmaceuticals (NASDAQ: REGN) shareholders saw significant losses when the stock dropped sharply following the May 16, 2026 disclosure that its Phase 3 melanoma trial of fianlimab + Libtayo failed to meet its primary endpoint versus Keytruda.