Skip to Content

Regeneron Pharmaceuticals, Inc.

Corporate Governance / Derivative

  • Date:
  • 7/17/2026
  • Company Name:
  • Regeneron Pharmaceuticals, Inc.
  • Stock Symbol:
  • REGN
  • Class Period:
  • FROM 8/1/2025 TO 5/15/2026
  • Status:
  • Investigating

Case Finder

Locate any case using the tools below.

Bragar Eagel & Squire, P.C., a nationally recognized shareholder rights law firm, is investigating potential claims against Regeneron Therapeutics, Inc. (NASDAQ:REGN) on behalf of long-term stockholders following a class action complaint that was filed against Regeneron on July 16, 2026 with a Class Period from August 1, 2025, and May 15, 2026. Our investigation concerns whether the board of directors of Regeneron have breached their fiduciary duties to the company.

The complaint alleges that the Company and its executives violated federal securities laws by making false and/or misleading statements and/or failing to disclose the true state of Regeneron's Phase III Fianlimab-Libtayo Study; notably, that its preliminary statistical assumptions were fundamentally flawed, that the active treatment arm was failing to achieve meaningful clinical differentiation over standard therapies, and that the trial would ultimately fail to reach statistical significance on its primary endpoint even without overperformance of the control arm.
 
Plaintiff alleges that April 29, 2026, during Regeneron's first quarter earnings call, defendants disclosed the Phase III Fianlimab-Libtayo Study had been altered, expanding the number of patients in the study eligible for "analysis of progression-free survival." On this news, the price of Regeneron's common stock declined from a closing market price of $731.77 per share on April 28, 2026, to $686.36 per share on April 29, 2026, a decline of about 6.2% in the span of just a single day. Then, after-market 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)."  On this news, the price of Regeneron's common stock declined from $698.25 per share on May 15, 2026, to $629.68 per share on May 18, 2026, a decline of about 9.8% in the span of one day.

If you are a long-term stockholder of Regeneron, have information, would like to learn more about these claims, or have any questions concerning this announcement or your rights or interests with respect to these matters, please contact Brandon Walker or  Melissa Fortunato by email at investigations@bespc.com, by telephone at (212) 355-4648, or by filling out the form below. There is no cost or obligation to you.
Contact Instructions
Please contact Brandon Walker or Melissa Fortunato by email at investigations@bespc.com with any questions about this case.
The individual or institution below (“Plaintiff”) has reviewed and agrees to the Bragar Eagel & Squire, P.C. (“BESPC”) retainer agreement and authorizes BESPC to prosecute an action on Plaintiff’s behalf under the federal securities laws or applicable state laws to recover damages on behalf of investors in Regeneron Pharmaceuticals. BESPC will prosecute the action on a full contingency basis and will forward all costs and expenses.
 

Case Finder

Locate any case using the tools below.

You may share a link to this page on any of the sites listed below or send link via email: