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Relay Therapeutics Announces Efficacy Subset Analysis of Zovegalisib (RLY-2608) + Fulvestrant in Breast Cancer Patients Pre-Treated with SERD or with ESR1 Mutations at SABCS 2025
Efficacy data remain consistent with previous disclosures, showing 10.3-month median PFS in all patients and 11.4-month median PFS in 2L patients Subset
About this update from Relay Therapeutics, Inc.
[{"type":"text","content":"Efficacy data remain consistent with previous disclosures, showing 10.3-month median PFS in all patients and 11.4-month median PFS in 2L patients Subset analyses show broad activity in patients with PI3Kα-mutated, HR+/HER2- metastatic breast cancer, regardless of prior fulvestrant or other SERD exposure, or ESR1 mutation status Phase 3 ReDiscover-2 trial in CDK4/6-experienced breast cancer ongoing CAMBRIDGE, Mass., Dec. 12, 2025 (GLOBE NEWSWIRE) -- Relay Therapeutics, Inc. (Nasdaq: RLAY), a clinical-stage, small molecule precision medicine company developing potentially life-changing therapies for patients living with cancer and genetic disease, today announced a subset analysis of interim clinical data for zovegalisib (RLY-2608), the first known investigational allosteric, pan-mutant and isoform-selective inhibitor of PI3Kα. These data are being presented today at the 2025 San Antonio Breast Cancer Symposium (SABCS). “Data presented today demonstrate the robust activity of zovegalisib + fulvestrant across subgroups of patients whose baseline characteristics are known to affect outcomes, such as prior fulvestrant or SERD and ESR1 mutation status,” said Don Bergstrom, M.D., Ph.D., President of R&D at Relay Therapeutics. “The broad range of activity highlights the importance of selectively targeting the driver of disease, mutant PI3Kα, and gives us confidence that the data observed to date should translate to our ongoing Phase 3 trial, ReDiscover-2.” ReDiscover – Zovegalisib First-in-Human Study Zovegalisib is currently being evaluated in ReDiscover, an ongoing first-in-human study, which was designed to evaluate the safety, tolerability, pharmacokinetics, pharmacodynamics and preliminary antitumor activity of zovegalisib in combination with fulvestrant, and in combination with fulvestrant and CDK inhibitors. 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 (BID) fasted, 44% of patients (n=28) had received two or more prior lines of therapy, 52% of patients (n=33) had received prior SERD (includes fu...