REGN Shareholder Alert: September 14, 2026 Lead Plaintiff Deadline in Regeneron Pharmaceuticals Securities Class Action - Contact SueWallSt

April 29, 2026: REGN declined from $731.77 to $686.36, a $45.41 per-share drop, or about 6.2%. May 18, 2026: REGN declined from $698.25 to $629.68, a $68.57 per-share drop, or about 9.8%. From the Class Period high, REGN lost $102.09 per share, or 13.95%. Lead plaintiff applications must be submitted by September 14, 2026.

Wall Street Reaction After the Protocol Amendment

The complaint alleges that Regeneron and certain executives minimized the significance of a prolonged slowdown in progression-free survival event accrual in the Phase III Fianlimab-Libtayo Study. On April 29, 2026, the Company disclosed that the primary analysis of progression-free survival would consider all enrolled patients with at least 6 months of follow-up.

Analysts allegedly reacted to that disclosure as a meaningful change in the study's risk profile. Wells Fargo reportedly cut its price target by 3% and stated that investor concern centered on whether expanding the PFS cohort suggested that the underlying benefit may be insufficient to show statistical significance.

Analyst Coverage Timeline

• Wells Fargo attributed REGN's April 29 share decline primarily to the Company's decision to expand the PFS cohort.
• The coverage indicated investor concern that the change could signal insufficient PFS benefit.
• Evercore ISI noted that a protocol amendment appeared necessary to support the timing of the readout.
• Evercore analysts allegedly observed that Regeneron's preliminary assumptions were materially off after the delay and amendment.
• The complaint contends that these analyst reactions called into question earlier positive statements about event accrual and study confidence.

Execution Concerns on Wall Street

As alleged, the analyst commentary focused less on the quarterly earnings backdrop and more on the clinical trial implications of the protocol change. The action claims the amendment raised questions about whether the study's original statistical assumptions and endpoint timing were reliable.

"When analyst expectations are built on incomplete or allegedly misleading company disclosures, the resulting corrections can cause significant investor harm. Here, the analyst reaction cited in the complaint is important because it connects the protocol amendment to investor concerns about statistical significance and trial execution." -- Joseph E. Levi, Esq.

Learn more about the case

WHY SUEWALLST: SueWallSt is powered by Levi & Korsinsky LLP. Levi & Korsinsky LLP has established itself as a nationally-recognized securities litigation firm that has secured hundreds of millions of dollars for aggrieved shareholders and built a track record of winning high-stakes cases. The firm has extensive expertise representing investors in complex securities litigation and a team of over 70 employees to serve our clients. For seven years in a row, Levi & Korsinsky has ranked in ISS Securities Class Action Services' Top 50 Report as one of the top securities litigation firms in the United States.

Frequently Asked Questions About the REGN Lawsuit

Q: What is the REGN class action lawsuit about? A: A securities class action has been filed against Regeneron Pharmaceuticals, Inc. (NASDAQ: REGN) alleging materially false and misleading statements between August 1, 2025 and May 15, 2026. Shares fell approximately 13.95% from the Class Period high after the Company disclosed a Phase III Fianlimab-Libtayo protocol amendment and later announced that the trial did not reach statistical significance for the primary endpoint of improvement in progression-free survival.

Q: How much did REGN stock drop? A: REGN shares fell $102.09 per share, or 13.95%, from the Class Period high of $731.77 on April 28, 2026 to $629.68 after the May 15, 2026 after-market announcement. Investors who purchased during the Class Period at allegedly inflated prices and suffered losses may be eligible to seek compensation.

Q: What is the REGN lead plaintiff deadline? A: The deadline to apply for lead plaintiff appointment is September 14, 2026. This deadline applies only to investors seeking to serve as lead plaintiff. Class members who do not apply may still participate in any recovery without taking action before this date.

Q: What if I already sold my REGN shares -- can I still recover losses? A: Yes. Eligibility is based on when you purchased, not whether you still hold the shares. Investors who bought during the Class Period and sold at a loss may still be eligible to participate.

Q: Do I need to go to court or give testimony? A: No. The overwhelming majority of class members never appear in court or give depositions. If there is a settlement or recovery, eligible class members generally submit a claim form to seek their portion.

Q: What does it cost me to participate? A: There is no upfront cost to contact the firm. Securities class actions are generally handled on a pure contingency basis. No upfront fees, no retainer, and no out-of-pocket costs. Any attorneys' fees and expenses awarded to class counsel are subject to court approval.

Q: What do REGN investors need to do right now? A: Investors may gather brokerage records showing purchase dates, share quantities, and prices paid. Contact Levi & Korsinsky for a free, no-obligation evaluation at jlevi@levikorsinsky.com or (212) 363-7500. No immediate action is required to remain eligible as an absent class member.

CONTACT:\

Levi & Korsinsky, LLP\

Joseph E. Levi, Esq.\

33 Whitehall Street, 27th Floor\

New York, NY 10004\

jlevi@SueWallSt.com\

Tel: (888) SueWallSt\

Fax: (212) 363-7171

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