Investors urged to act quickly in Regeneron securities lawsuit
News provided byRegeneron Pharmaceuticals, Inc · 2 min read
New York, New York, September 6, 2026, Faruqi & Faruqi, LLP, a leading national securities law firm, is reminding investors who purchased Regeneron Pharmaceuticals, Inc. (NASDAQ: REGN) securities between August 1, 2025, and May 15, 2026, of the impending deadline to seek the role of lead plaintiff in a federal securities class action lawsuit filed against the company.
The lawsuit, filed on behalf of investors by Faruqi & Faruqi, LLP, alleges that Regeneron and certain of its executives violated federal securities laws by making false and misleading statements and failing to disclose the true state of the company's Phase III Fianlimab-Libtayo study. Specifically, the complaint states that the company’s preliminary statistical assumptions were fundamentally flawed, the active treatment arm was failing to achieve meaningful clinical differentiation over standard therapies, and the trial ultimately failed 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." This news caused Regeneron’s stock price to drop by 6.2%, closing at $686.36 per share. On May 15, 2026, the company announced that the "Phase 3 Trial of Fianlimab" did not reach statistical significance for the primary endpoint of improvement in progression-free survival, leading to a further 9.8% decline in the stock price, which closed at $629.68 per share.
Faruqi & Faruqi, LLP is urging investors who suffered losses during this period to contact partner Josh Wilson directly at 877-247-4292 or 212-983-9330 (Ext. 1310) to discuss their legal rights and options. The firm is also encouraging anyone with relevant information regarding Regeneron’s conduct to come forward, including whistleblowers, former employees, and shareholders.
The deadline for investors to seek appointment as lead plaintiff is September 14, 2026. The lead plaintiff is the investor with the largest financial interest in the relief sought by the class who is adequate and typical of class members and directs and oversees the litigation on behalf of the putative class. Any member of the putative class may move the court to serve as lead plaintiff through counsel of their choice or choose to remain an absent class member.
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