Erasca Inc. shares plunged 48%, wiping out $2.8 billion in market value, after a patient death and a patent infringement claim from Revolution Medicines.
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Erasca loses $2.8 billion after patient death, patent infringement suit
Erasca Inc. shares plunged 48%, wiping out $2.8 billion in market value, after a patient death and a patent infringement claim from Revolution Medicines.
"We're investigating whether Erasca may have intentionally misled investors about ERAS-0015's safety profile and about a potential moat in its particular, highly competitive cancer treatment space," Reed Kathrein, the Hagens Berman partner leading the firm's investigation, said.
The securities class action, filed in the US District Court for the Southern District of California, covers investors who bought Erasca common stock between Jan. 14, 2025 and April 26, 2026. The complaint alleges Erasca improperly compared its ERAS-0015 40-milligram dose cohort to Revolution Medicines' RMC-6236 400-milligram dose cohort and made misleading statements about its intellectual property protection. As recently as March 12, 2026, Erasca assured investors it had "in-licensed one patent family from Joyo" that included one issued US patent and 13 pending foreign patent applications.
The truth emerged April 27, 2026, when Erasca disclosed before market open that Revolution Medicines had sent a letter challenging the validity of its IP claims and alleging trade secret misappropriation through a third party. After the close, the company revealed a patient who received 24 milligrams of ERAS-0015 died about one month after starting treatment. The stock fell about 11% on the first disclosure and another 48% after the second, erasing $2.8 billion in market capitalization.
ERAS-0015 is an investigational oral pan-RAS molecular glue being developed for RAS-mutant solid tumors, including pancreatic ductal adenocarcinoma. The drug was positioned as a potential best-in-class candidate in a highly competitive space that includes Revolution Medicines' RMC-6236 and other RAS-targeting therapies.
The lawsuit names Erasca and certain top executives as defendants. The lead plaintiff deadline is Aug. 10, 2026. Multiple law firms including Hagens Berman, Kahn Swick & Foti, and Robbins Geller Rudman & Dowd are representing investors in the class action.
The class action and patient death cast doubt on ERAS-0015's future as a core pipeline asset. Investors will watch for potential FDA clinical holds, any injunction from Revolution Medicines' patent challenge, and whether the company can provide updated safety data from its ongoing Phase 1 trial.
This article is for informational purposes only and does not constitute investment advice.
[1] Erasca, Inc. (ERAS) Faces Securities Class Action Amid Patient Death, Intellectual Property Questions, $2.8 Billion Market Cap Loss – Hagens Berman[2] Erasca, Inc. (ERAS) Faces Securities Class Action Amid Patient D - GuruFocus[3] Erasca, Inc. (ERAS) Faces Securities Class Action Amid Patient Death, Intellectual Property Questions, $2.8 Billion Market Cap Loss -- HBSS - PR Newswire[4] Erasca, Inc. Notice of August 10, 2026 Application Deadline for Class Action Lawsuit - Contact Lewis Kahn, Esq. at Kahn Swick & Foti, LLC, Before Application Deadline - TMX Newsfile[5] INVESTOR NOTICE: Robbins Geller Rudman & Dowd LLP Announces - GlobeNewswire
