SHAREHOLDER ALERT: Levi & Korsinsky, LLP Notifies Investors It Has Filed a Complaint to Recover Losses Suffered by Purchasers of Regeneron Pharmaceuticals, Inc. Common Stock and Sets a Lead Plaintiff Deadline of September 14, 2026

Levi & Korsinsky, LLP has filed a complaint to recover losses suffered by purchasers of Regeneron Pharmaceuticals, Inc. common stock (NASDAQ: REGN) between August 1, 2025, and May 15, 2026, inclusive. The class action lawsuit alleges that defendants provided overwhelmingly positive statements to investors while disseminating materially false and misleading statements and/or concealing material adverse facts concerning the true state of Regeneron’s Phase III Fianlimab-Libtayo Study. Specifically, the complaint states that its preliminary statistical assumptions were fundamentally flawed, the active treatment arm was failing to achieve meaningful clinical differentiation over standard therapies, and the trial would ultimately fail to reach statistical significance on its primary endpoint. On April 29, 2026, Regeneron disclosed that the Phase III Fianlimab-Libtayo Study had been altered, expanding the number of patients eligible for “analysis of progression-free survival.” Following this news, Regeneron’s stock price declined about 6.2%. On May 15, 2026, Regeneron announced that the “Phase 3 Trial of Fianlimab . . . did not reach statistical significance for the primary endpoint of improvement in progression-free survival (PFS).” Following this news, Regeneron’s stock price declined further. “Our firm is committed to ensuring that investors receive full compensation for losses caused by corporate misrepresentations,” said Joseph E. Levi, a partner at Levi & Korsinsky. “We encourage REGN shareholders to step forward before the September 14, 2026 deadline so we can pursue justice on their behalf.” If you suffered a loss in REGN common stock, you have until September 14, 2026 to request that the Court appoint you as lead plaintiff.