Relay Therapeutics Announces Subset Analysis of Zovegalisib Clinical Data

Relay Therapeutics announced a subset analysis of interim clinical data for zovegalisib, the first known investigational allosteric, pan-mutant and isoform-selective inhibitor of PI3Kalpha. These data are being presented at the 2025 San Antonio Breast Cancer Symposium, SABCS. ReDiscover - Zovegalisib First-in-Human Study: As of the data cut-off date of October 15, 2025, 118 patients had enrolled into the zovegalisib + fulvestrant arm of the ReDiscover study. Across all doses, all patients had received a significant level of prior therapy in the advanced setting, including at least one prior endocrine therapy and at least one prior CDK4/6 inhibitor. Among the 64 patients who received 600mg twice daily fasted, 44% of patients had received two or more prior lines of therapy, 52% of patients had received prior SERD, and 29% of patients had detectable ESR1 mutations at baseline. Efficacy Consistent Across Subset Populations: The median progression free survival was 10.3 months for all patients. Among the total of 31 patients with measurable disease, objective response rate was 39%. For second line patients, median PFS was 11.4 months and ORR was 47%. Efficacy was generally consistent across other subsets of patients. For patients who received prior SERD, median PFS was 11.4 months and ORR was 44%, and for patients who had a detectable ESR1 mutation at baseline, median PFS was 8.8 months and ORR was 60%. The overall tolerability profile remained consistent with mutant-selective PI3Kalpha inhibition, with treatment-related adverse events that were mostly low-grade, manageable and reversible