Erasca Faces Class Action Lawsuit Following Patent and Safety Disclosures

The legal action follows a tumultuous two-day period in April 2026. On April 27, Erasca disclosed a letter from Revolution Medicines, Inc. claiming that Erasca’s ERAS-0015 drug candidate infringes on U.S. Patent No. 12,409,225 and involves trade secret misappropriation. RevMed further accused the company of using deceptive comparative data between ERAS-0015 and RMC-6236. Erasca’s stock dropped 10.71% to $19.50 following the disclosure.

Market volatility intensified after hours on April 27 when Erasca reported preliminary Phase 1 clinical data, revealing the death of a patient who had received 24 mg of ERAS-0015. The patient suffered from Grade 3 pneumonitis that escalated to a fatal Grade 5 outcome. The company subsequently clarified that its comparative performance claims were based on limited cross-study analyses rather than head-to-head trials. Following these reports, Erasca shares plunged an additional 48.3% to close at $9.90 on April 28.