On May 25, 2023, Erasca, Inc. announced promising preliminary data for ERAS-007 combinations in patients with gastrointestinal malignancies as part of two poster presentations that will be presented at the American Society of Clinical Oncology Annual Meeting in Chicago, Illinois. In the Phase 1b/2 HERKULES-3 trial in patients with metastatic BRAF V600E mutated colorectal cancer (CRC), promising preliminary clinical activity of ERAS-007 in combination with encorafenib and cetuximab (EC) include: 40% (2/5) response rate and 60% (3/5) disease control rate (CR+PR+SD) in EC-naïve response evaluable patients at the highest dose of ERAS-007 tested (100 mg BID-QW (twice daily on day 1 of each week)), with duration of exposure for both responders > 34 weeks as of the data cutoff date; across all dose levels in EC-naïve response evaluable patients, 29% (2/7) response rate and 57% (4/7) disease control rate; ERAS-007 in combination with EC was generally well-tolerated with mostly low-grade treatment-related adverse events at all combination doses tested; ne dose-limiting toxicity (DLT) was reported for ERAS-007 100 mg BID-QW in combination with EC (Grade 3 macular edema, N=1); and pharmacokinetic (PK) exposures of ERAS-007, encorafenib, and cetuximab were comparable to monotherapy values, suggesting no clinically significant PK drug-drug interactions between the study drugs. Data cutoff date of March 23, 2023.

The Company expects additional HERKULES-3 Phase 1b combination data in EC-naïve patients with BRAF-mutated CRC between H2 2023 and H1 2024. In the Phase 1b/2 HERKULES-3 trial in patients with KRAS/NRAS mutant CRC or KRASm pancreatic ductal adenocarcinoma (PDAC), preliminary results from ERAS-007 in combination with palbociclib demonstrated a lack of clinical activity in patients with KRAS/NRAS mutant CRC and KRAS mutant PDAC. Based on these data, the Company will not pursue the combination of ERAS-007 and palbociclib in this patient population.