Erasca announced initial results from its Phase I dose‐escalation study of ERAS-0015 in patients with advanced solid tumors harboring various RAS mutations. At dose levels as low as 8 mg once daily, the company observed two confirmed partial responses and one unconfirmed partial response across three different tumor types. Response durations exceeded six months in two patients, and disease control (objective response plus stable disease) was achieved in 75% of evaluable participants. Importantly, no dose-limiting toxicities were reported, and the majority of adverse events were Grade 1 or 2, with fatigue and nausea being the most common.

Erasca reported that the ERAS-0015 study enrolled 30 patients within three months of the first dose administration, outpacing the original enrollment forecast by 50%. This rapid recruitment was driven by streamlined site activation and strong investigator interest in RAS-mutant indications. The company now anticipates initiating monotherapy expansion cohorts in the second half of 2026 and plans to begin combination cohorts with MEK inhibitors by year-end. The accelerated timeline could support a pivotal Phase II study initiation as early as mid-2027.

Following the data release and enrollment update, Erasca’s share price surged 42% over five trading sessions, marking the largest weekly gain since the company’s IPO. Trading volume during that period averaged 3.2 million shares per day, more than triple the 30-day average, indicating heightened retail and institutional interest. Market analysts have revised their consensus recommendations upward, citing ERAS-0015’s early activity and clean safety profile as catalysts for potential partnership or acquisition discussions.

Erasca expects to present updated ERAS-0015 monotherapy data, including pharmacokinetics and biomarker correlations, at a major oncology conference in June 2026. The company is in ongoing dialogue with regulatory agencies regarding a potential accelerated approval pathway, leveraging the unmet need in RAS-driven cancers. Additionally, Erasca plans to file an investigational new drug application for ERAS-4001, a second RAS-targeting candidate, by the end of the year, positioning its RAS franchise for a rapid series of clinical readouts through 2028.