Erasca’s shares fell sharply after the company disclosed a fatal adverse event connected to ERAS-0015, its oral pan-RAS molecular glue in early trials. The disclosure accompanied preliminary dose-escalation data, including unconfirmed response rates across KRAS G12X NSCLC and PDAC cohorts, but the investor materials referenced a Grade 3 pneumonitis case that progressed to Grade 5 after supportive care was withdrawn at the patient’s direction.