Snapshot from Aug 24, 2026 at 07:00 UTC. For live data and tracking: View Live
Events / Regulatory / Regeneron Securities Class Action...
Regulatory securities class action

Regeneron Securities Class Action Over Trial Failure

Analysis based on 182 articles · First reported Jul 16, 2026 · Last updated Aug 23, 2026

Sentiment
-60
Attention
4
Articles
182
Market Impact
General
Live prominence charts, article sentiment distribution, and event development timeline available on the Ergen Dashboard
Market Impact

The failed trial and subsequent securities class actions have significantly eroded investor confidence in Regeneron, leading to a sharp decline in its stock price and an $11 billion market cap loss. The litigation could result in substantial financial penalties and reputational damage, further pressuring the company's valuation and future prospects.

Pharmaceuticals Biotechnology
Event Summary

Regeneron Pharmaceuticals faces multiple securities class action lawsuits filed by several law firms, including Bronstein, Gewirtz & Grossman, LLC, Hagens Berman, The Schall Law Firm, Faruqi & Faruqi, Pomerantz LLP, DJS Law Group, Robbins LLP, The Gross Law Firm, SueWallSt, and BFA Law. The lawsuits allege that Regeneron and certain officers made materially false and misleading statements regarding its Phase III Fianlimab-Libtayo study for melanoma. Specifically, the company failed to disclose that the study's statistical assumptions were flawed, the active treatment arm was not showing meaningful differentiation, and the trial was unlikely to achieve its primary endpoint. On April 29, 2026, Regeneron disclosed a protocol alteration, causing its stock to drop 6.2%. On May 15, 2026, the company announced the trial failed to reach statistical significance, leading to a further 9.8% decline and an $11 billion market cap wipeout. Investors who purchased shares between August 1, 2025 and May 15, 2026 are eligible to join the class action, with a lead plaintiff deadline of September 14, 2026.

Key Actions
94 Levi & Korsinsky notified investors of lawsuit Regeneron Pharmaceuticals
90 Bronstein, Gewirtz & Grossman, LLC filed class action Regeneron Pharmaceuticals
90 Regeneron Pharmaceuticals disclosed trial failure
90 Regeneron Pharmaceuticals lost market cap
90 Regeneron Pharmaceuticals announced failed endpoint
87 Bleichmar Fonti & Auld LLP filed class action Regeneron Pharmaceuticals
85 Hagens Berman filed lawsuit Regeneron Pharmaceuticals
85 Faruqi & Faruqi filed securities class action Regeneron Pharmaceuticals
85 Hagens Berman altered trial protocol
85 Regeneron Pharmaceuticals admitted slow event rates
80 Pomerantz LLP filed class action Regeneron Pharmaceuticals
80 Regeneron Pharmaceuticals misled investors
80 Regeneron Pharmaceuticals disclosed protocol alteration
79 Regeneron Pharmaceuticals announced trial expansion
77 Pomerantz LLP investigates claims Regeneron Pharmaceuticals
+ 14 more actions View on Dashboard
Entities Involved
stock
Regeneron Pharmaceuticals
Regeneron is the defendant in multiple securities class actions alleging securities fraud related to its failed Phase III Fianlimab-Libtayo trial. The company's stock dropped sharply, wiping out $11 billion in market cap, and it faces potential financial and reputational damage.
Importance 100.0 Sentiment -80.0
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Bronstein, Gewirtz & Grossman, LLC
Bronstein, Gewirtz & Grossman, LLC filed a class action lawsuit against Regeneron and is actively soliciting investors to join, positioning itself to recover damages for shareholders.
Importance 70.0 Sentiment 20.0
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Hagens Berman
Hagens Berman filed a securities class action and is leading an investigation into Regeneron's alleged misleading statements, seeking to represent investors with substantial losses.
Importance 70.0 Sentiment 20.0
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Pomerantz LLP
Pomerantz LLP filed a class action lawsuit against Regeneron, alleging securities fraud and seeking to represent affected investors.
Importance 50.0 Sentiment 10.0
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Faruqi & Faruqi
Faruqi & Faruqi filed a securities class action against Regeneron and is reminding investors of the September 14, 2026 deadline to seek lead plaintiff status.
Importance 50.0 Sentiment 10.0
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The Schall Law Firm
The Schall Law Firm filed a class action lawsuit against Regeneron, reminding investors of the lead plaintiff deadline and seeking to recover losses for shareholders.
Importance 50.0 Sentiment 10.0
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DJS Law Group
DJS Law Group filed a class action lawsuit against Regeneron, reminding shareholders of the lead plaintiff deadline and seeking to recover losses.
Importance 40.0 Sentiment 10.0
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Robbins LLP
Robbins LLP filed a class action lawsuit against Regeneron and is encouraging investors to contact them regarding lead plaintiff appointment.
Importance 40.0 Sentiment 10.0
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BFA Law
BFA Law filed a class action lawsuit against Regeneron, urging investors to contact them by the September 14 deadline.
Importance 40.0 Sentiment 10.0
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Peretz Bronstein
Peretz Bronstein is the founding partner of Bronstein, Gewirtz & Grossman, LLC and is actively involved in announcing the class action against Regeneron.
Importance 30.0 Sentiment 10.0
govactor
United States — United States Securities and Exchange Commission
The SEC is referenced as the regulator under whose rules the securities claims are brought, and its whistleblower program is mentioned as a potential avenue for information.
Importance 30.0 Sentiment 0.0
per
Reed Kathrein
Reed Kathrein is the Hagens Berman partner leading the investigation into Regeneron's alleged misleading statements and the resulting class action.
Importance 30.0 Sentiment 10.0
per
Brian Schall
Brian Schall is a partner at The Schall Law Firm, which filed a class action against Regeneron.
Importance 20.0 Sentiment 5.0
per
Danielle Peyton
Danielle Peyton is a contact at Pomerantz LLP for investors interested in the class action.
Importance 20.0 Sentiment 5.0
per
David Schwartz (disambiguation)
David Schwartz (disambiguation) is a contact at DJS Law Group for investors interested in the class action. He is involved in the litigation.
Importance 10.0 Sentiment 0.0
+ 1 more entities View on Dashboard
Relationships
Bronstein, Gewirtz & Grossman, LLC related ↔ Hagens Berman
Bronstein, Gewirtz & Grossman, LLC co-plaintiffs ↔ Pomerantz LLP Bronstein, Gewirtz & Grossman, LLC frequently collaborates with Pomerantz LLP as co-plaintiffs in numerous class action
Bronstein, Gewirtz & Grossman, LLC co-counsel ↔ Faruqi & Faruqi Bronstein, Gewirtz & Grossman, LLC frequently acts as co-counsel with Faruqi & Faruqi LLP in numerous securities class a
Bronstein, Gewirtz & Grossman, LLC co-counsel ↔ The Schall Law Firm Bronstein, Gewirtz & Grossman, LLC frequently collaborates with The Schall Law Firm as co-counsel in numerous securities
Bronstein, Gewirtz & Grossman, LLC co-plaintiffs ↔ DJS Law Group Bronstein, Gewirtz & Grossman, LLC frequently acts as a co-plaintiff with DJS Law Group in numerous securities fraud cla
Bronstein, Gewirtz & Grossman, LLC co-counsel ↔ Robbins LLP Bronstein, Gewirtz & Grossman, LLC frequently serves as co-counsel with Robbins LLP in numerous securities class action
Bronstein, Gewirtz & Grossman, LLC related ↔ BFA Law
Bronstein, Gewirtz & Grossman, LLC related ↔ Peretz Bronstein
Hagens Berman co-counsel ↔ Pomerantz LLP Hagens Berman frequently acts as co-counsel with Pomerantz LLP in various securities fraud and class action lawsuits, re
Hagens Berman co-plaintiff ↔ Faruqi & Faruqi Hagens Berman frequently acts as co-plaintiff or co-counsel with Faruqi & Faruqi in various securities class action laws
Hagens Berman competitor ↔ The Schall Law Firm Hagens Berman competes directly with The Schall Law Firm in the plaintiff-side securities class action market.
Hagens Berman co-plaintiff ↔ DJS Law Group Hagens Berman frequently collaborates with DJS Law Group as co-counsel on various securities fraud class action lawsuits
Hagens Berman related ↔ Robbins LLP
Hagens Berman related ↔ BFA Law
Hagens Berman related ↔ Peretz Bronstein
+ 21 more relationships View on Dashboard
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