Ideaya Biosciences to present initial data from Phase 1/2 trial of IDE397

IDEAYA Biosciences (IDYA) will present initial data at their 10-Year Anniversary R&D Day from two expansion cohorts in their Phase 1/2 combination trial of IDE397, a potential first-in-class, small molecule adenosyltransferase 2a inhibitor, in combination with Gilead’s Trodelvy, a Trop2-directed antibody-drug conjugate, in patients with late-line methylthioadenosine phosphorylase-deletion urothelial cancer. MTAP-deletion is estimated to occur in approximately 25-30% of UC and 15-20% of non-small cell lung cancer patients. Summary of key findings: To date, median progression free survival and duration of response has not been reached. 33% ORR at DL1; 3 confirmed partial responses, including one patient with a confirmed response after the cut-off date, and 57% ORR at DL2. The preliminary combination data is trending favorably versus historical Trodelvy monotherapy efficacy reported in metastatic UC, including 11% ORR in patients post-EV therapy and 23% ORR in predominantly EV-naive patients. Manageable safety profile consistent with known adverse events of both drugs as single agents, with no treatment related serious adverse events observed at the IDE397 30mg and Trodelvy 7.5 mg/kg expansion dose. The most common Grade 3 or greater treatment-related adverse events seen in DL1 were anemia and neutropenia, and in DL2 were anemia, asthenia, and diarrhea.