Erasca’s shares sank 53% amid disclosure around a death connected to ERAS-0015’s treatment-related adverse event timeline in earlier data. The precision oncology company developing an oral pan-RAS molecular glue reported unconfirmed overall response rates of 62%–75% in KRAS G12X NSCLC at 16–32 mg once daily and 40%–50% in second-line KRAS G12X PDAC. However, the investor presentation footnotes described a 66-year-old male patient who died after grade 3 pneumonitis progressed to grade 5 after supportive care was withdrawn at the patient’s direction. Erasca said the patient was heavily pretreated and had pulmonary metastases with a history of right lung cryoablation, and no lung radiation. Erasca’s CEO Jonathan E. Lim told analysts during an April 27 call that the death represented a “very rare event,” noting pneumonitis is an uncommon drug-related toxicity across oncology therapies. The episode highlights how single-patient safety disclosures can rapidly shift sentiment and complicate investor interpretation of early dose-escalation efficacy datasets.