Regeneron shares dropped sharply after the Company’s Phase 3 melanoma trial of fianlimab + Libtayo failed its primary endpoint against Keytruda – wiping out billions in market value in a single session.
NEW YORK, May 21, 2026 (GLOBE NEWSWIRE) — Regeneron Pharmaceuticals, Inc. (NASDAQ: REGN) lost significant market capitalization on May 16, 2026, when the Company disclosed that its Phase 3 melanoma trial of fianlimab combined with Libtayo failed to meet its primary endpoint versus Merck’s Keytruda. Shareholders who lost money on REGN are encouraged to submit their information here. You may also contact Joseph E. Levi, Esq. via email at [email protected] or by telephone at (212) 363-7500.
The fianlimab + Libtayo combination represented one of Regeneron’s highest-profile late-stage oncology programs. Wall Street analysts had modeled significant revenue contributions from the melanoma indication, with multiple firms carrying price targets that reflected successful commercialization. The May 16 disclosure that the combination did not demonstrate superiority over Keytruda – the current standard of care in first-line metastatic melanoma – triggered immediate and broad-based selling pressure across REGN shares.
Prior to the trial readout, Regeneron executives had previously during heathcare conferences characterized a delay in the timing readout as a mere “slowing of event rates” that they “believe[d]” was triggered by “the test arms performing well.” The stock’s sharp decline on May 16 reflected the distance between the positive characterization and the actual outcome disclosed.
If you purchased Regeneron shares and suffered a loss, click here to discuss your legal rights. You may also contact Joseph E. Levi, Esq. via email at [email protected] or by telephone at (212) 363-7500.
ABOUT THE FIRM – For over two decades, Levi & Korsinsky has represented shareholders in securities investigations and recoveries. Ranked in ISS Top 50 for seven consecutive years.
Frequently Asked Questions About the REGN Investigation
Q: Who is eligible to participate in the REGN investigation? A: Investors who purchased REGN stock or securities and suffered financial losses may be eligible. Eligibility is based on purchase date and documented losses – not on whether you still hold the shares.
Q: How much did REGN stock drop? A: Shares fell sharply on May 16, 2026, after Regeneron disclosed that its Phase 3 melanoma trial of fianlimab + Libtayo failed to meet its primary endpoint versus Keytruda. Investors who purchased shares before this disclosure may be entitled to recovery.
Q: What do REGN investors need to do right now? A: Gather brokerage records including purchase dates, share quantities, and prices paid. Contact Levi & Korsinsky for a free, no-obligation evaluation at [email protected] or (212) 363-7500. No immediate action is required to remain eligible to participate in the investigation.
Q: What happens after I contact Levi & Korsinsky? A: An attorney will review your trading history at no cost and provide an initial assessment of your potential recovery.
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 REGN and sold at a loss may still participate in the investigation.
Q: What does it cost me to participate? A: Nothing. Securities investigations are handled on a pure contingency basis. No upfront fees, no retainer, no out-of-pocket costs.
Q: What if I live outside the United States? A: U.S. securities fraud investigations generally cover purchases on U.S. exchanges regardless of the investor’s country of residence.
CONTACT:
Levi & Korsinsky, LLP
Joseph E. Levi, Esq.
Ed Korsinsky, Esq.
33 Whitehall Street, 27th Floor
New York, NY 10004
[email protected]
Tel: (212) 363-7500
Fax: (212) 363-7171
