Grabar Law Office is investigating claims on behalf of shareholders of Regeneron Pharmaceuticals, Inc. (NASDAQ: REGN). The investigation concerns whether certain officers and directors breached the fiduciary duties they owed to the company.

Regeneron Pharmaceuticals, Inc. discovers, invents, develops, manufactures, and commercializes medicines to treat various diseases worldwide. The company develops product candidates to treat eye, allergic and inflammatory, cardiovascular, metabolic, neurological, infectious, and rare diseases; and cancer, hematologic conditions. It also offers EYLEA injections for wet age-related macular degeneration and diabetic macular edema; myopic choroidal neovascularization; diabetic retinopathy; neovascular glaucoma; retinopathy of prematurity; Dupixent injection to treat atopic dermatitis and asthma; Libtayo injection for metastatic or locally advanced cutaneous squamous cell carcinoma; Praluent injection to treat heterozygous familial hypercholesterolemia (HoFH); and Kevzara solution for rheumatoid arthritis.

WHY? On May 15, 2026, Regeneron issued a press release disclosing that "results from the Phase 3 trial evaluating two dose levels of fianlimab (LAG-3 inhibitor) in combination with cemiplimab (PD-1 inhibitor) as a first-line treatment for patients with unresectable locally advanced or metastatic melanoma" "did not each statistical significance for the primary endpoint of improvement in progression-free survival (PFS) compared to pembrolizumab (PD-1 inhibitor) monotherapy." Following this news, Regeneron's stock price dropped $68.57 per share, or 9.82%, to close at $629.68 on May 16, 2026.

WHAT YOU CAN DO NOW: If you are a long-term Regeneron Pharmaceuticals, Inc. (NASDAQ: REGN) shareholder, you are encouraged to contact Joshua Grabar at jgrabar@grabarlaw.com, or call 267-507-6085.  You can seek corporate reforms, the return of funds back to the company, and a court approved incentive award at no cost to you whatsoever.