---
title: "INVESTOR ALERT: Pomerantz Law Firm Reminds Investors with Losses on their Investment in Regeneron Pharmaceuticals, Inc. of Class Action Lawsuit and Upcoming Deadlines - REGN"
type: "News"
locale: "en"
url: "https://longbridge.com/en/news/298613745.md"
description: "Pomerantz LLP announced a class action lawsuit against Regeneron Pharmaceuticals (NASDAQ: REGN) for alleged securities fraud. The suit follows stock drops of 6.21% and 9.82% after the company disclosed issues with its Phase III Fianlimab-Libtayo study results. Investors who purchased Regeneron securities during the class period are advised to contact the firm by September 14, 2026, to potentially serve as Lead Plaintiff."
datetime: "2026-09-10T14:45:57.000Z"
locales:
  - [zh-CN](https://longbridge.com/zh-CN/news/298613745.md)
  - [en](https://longbridge.com/en/news/298613745.md)
  - [zh-HK](https://longbridge.com/zh-HK/news/298613745.md)
generator: "portal-rs"
---

# INVESTOR ALERT: Pomerantz Law Firm Reminds Investors with Losses on their Investment in Regeneron Pharmaceuticals, Inc. of Class Action Lawsuit and Upcoming Deadlines - REGN

, /PRNewswire/ -- Pomerantz LLP announces that a class action lawsuit has been filed against Regeneron Pharmaceuticals, Inc. ("Regeneron" or the "Company") (NASDAQ: REGN). Such investors are advised to contact Danielle Peyton at \[email protected\] or 646-581-9980, (or 888.4-POMLAW), toll-free, Ext. 7980. Those who inquire by e-mail are encouraged to include their mailing address, telephone number, and the number of shares purchased.

The class action concerns whether Regeneron and certain of its officers and/or directors have engaged in securities fraud or other unlawful business practices. 

**You have until September 14, 2026, to ask the Court to appoint you as Lead Plaintiff for the class if you purchased or otherwise acquired Regeneron securities during the Class Period. A copy of the Complaint can be obtained at www.pomerantzlaw.com.** 

**\[Click here for information about joining the class action\]**

On April 29, 2026, during during Regeneron's first quarter earnings call, the Company disclosed that 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, Regeneron's stock price fell $45.41 per share, or 6.21%, to close at $686.36 per share on April 29, 2026. 

Then, on May 15, 2026, Regeneron issued a press release disclosing 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, Regeneron's stock price fell $68.57 per share, or 9.82%, to close at $629.68 per share on May 16, 2026.

Pomerantz LLP, with offices in New York, Chicago, Los Angeles, London, Paris, and Tel Aviv, is acknowledged as one of the premier firms in the areas of corporate, securities, and antitrust class litigation. Founded by the late Abraham L. Pomerantz, known as the dean of the class action bar, Pomerantz pioneered the field of securities class actions. Today, more than 85 years later, Pomerantz continues in the tradition he established, fighting for the rights of the victims of securities fraud, breaches of fiduciary duty, and corporate misconduct. The Firm has recovered numerous multimillion-dollar damages awards on behalf of class members. See www.pomlaw.com. 

Attorney advertising. Prior results do not guarantee similar outcomes. 

**CONTACT:**  
Danielle Peyton  
Pomerantz LLP  
\[email protected\]  
646-581-9980 ext. 7980 

SOURCE Pomerantz LLP

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---
> **Disclaimer: This article is for reference only and does not constitute any investment advice.**