Erasca Inc. Hit with Securities Class Action Following Patent Dispute and Patient Death, Market Value Drops $2.8 Billion

Erasca, Inc. (NASDAQ: ERAS), a precision oncology company, is confronting a securities class action lawsuit following a dramatic 48% drop in its stock price, equating to a $9.25 per share loss and erasing over $2.8 billion in market capitalization. The decline followed public disclosures involving a patent infringement accusation by Revolution Medicines (RevMed) and the death of a patient treated with Erasca’s investigational pan-RAS molecular glue, ERAS-0015.

The class action seeks to represent investors who purchased or otherwise acquired Erasca common stock between January 14, 2025, and April 26, 2026. National shareholder rights law firm Hagens Berman Sobol Shapiro LLP is leading the investigation into whether Erasca violated federal securities laws by allegedly misleading investors about the safety and intellectual property status of ERAS-0015.

ERAS-0015 is Erasca’s oral, investigational drug candidate targeting RAS-mutant solid tumors, including pancreatic ductal adenocarcinoma. The company had positioned ERAS-0015 as a potentially "best-in-class" pan-RAS molecular glue. Prior to the lawsuit, Erasca publicly compared the efficacy of its 40 milligram dose cohort of ERAS-0015 to Revolution Medicines’ 400 milligram dose cohort of RMC-6236.

According to the complaint, Erasca assured investors as recently as March 12, 2026, that ERAS-0015’s intellectual property was well protected. The company highlighted that it had in-licensed a patent family from Joyo, which included one issued U.S. patent, one pending U.S. non-provisional patent application, one issued foreign patent, and thirteen pending foreign patent applications.

However, the complaint alleges these statements were misleading because the comparisons to RevMed’s RMC-6236 were improper and exposed Erasca to intellectual property disputes. The suit contends that Erasca’s representations about ERAS-0015 lacked a reasonable basis and misled the market.

The truth surfaced on April 27, 2026, when Erasca disclosed two critical developments. Before the market opened, the company revealed it had received a letter from RevMed’s legal counsel challenging the validity of Erasca’s intellectual property claims. RevMed alleged that Erasca had obtained its trade secrets through third-party misappropriation and had deceptively compared the competing therapies.

Later that day, after market close, Erasca disclosed that a patient treated with ERAS-0015 suffered an adverse event, presented to the emergency room one month after receiving the treatment, and subsequently died.

These disclosures triggered a swift market reaction, with Erasca’s share price falling sharply the following day, wiping out billions in market value.

Reed Kathrein, a partner at Hagens Berman leading the investigation, stated, "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."

Investors who acquired Erasca stock during the class period and suffered significant losses are encouraged to contact Hagens Berman to discuss their rights. The firm has set a lead plaintiff deadline of August 10, 2026.

Additionally, individuals with non-public information about Erasca are urged to consider assisting the investigation or participating in the SEC Whistleblower program, which offers rewards of up to 30% of any successful recovery.

Hagens Berman Sobol Shapiro LLP is a global plaintiffs’ rights firm specializing in complex litigation and corporate accountability. The firm has secured over $2.9 billion in recoveries for investors and other clients harmed by corporate misconduct.