San Francisco – September 10, 2026 -- Hagens Berman Sobol Shapiro LLP has filed a securities class action against Regeneron Pharmaceuticals (NASDAQ: REGN) after the failure of a Phase 3 melanoma trial wiped out $11 billion in market capitalization. The suit covers investors who purchased Regeneron shares between August 1, 2025, and May 15, 2026, with a lead plaintiff deadline set for September 14, 2026.