{"id":919200,"date":"2025-12-12T07:04:45","date_gmt":"2025-12-12T12:04:45","guid":{"rendered":"https:\/\/www.marketnewsdesk.com\/index.php\/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\/"},"modified":"2025-12-12T07:04:45","modified_gmt":"2025-12-12T12:04:45","slug":"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","status":"publish","type":"post","link":"https:\/\/www.marketnewsdesk.com\/index.php\/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\/","title":{"rendered":"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"},"content":{"rendered":"
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\n 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<\/em>\n <\/p>\n

\n Subset analyses show broad activity in patients with PI3K\u03b1-mutated, HR+\/HER2- metastatic breast cancer, regardless of prior fulvestrant or other SERD exposure, or <\/em>ESR1 mutation status<\/em><\/p>\n

\n Phase 3 ReDiscover-2 trial in CDK4\/6-experienced breast cancer ongoing<\/em>\n <\/p>\n

CAMBRIDGE, Mass., Dec. 12, 2025 (GLOBE NEWSWIRE) — Relay Therapeutics, Inc.<\/a> (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 PI3K\u03b1. These data are being presented today at the 2025 San Antonio Breast Cancer Symposium (SABCS).<\/p>\n

\u201cData 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<\/em> mutation status,\u201d said Don Bergstrom, M.D., Ph.D., President of R&D at Relay Therapeutics. \u201cThe broad range of activity highlights the importance of selectively targeting the driver of disease, mutant PI3K\u03b1, and gives us confidence that the data observed to date should translate to our ongoing Phase 3 trial, ReDiscover-2.\u201d<\/p>\n

\n ReDiscover \u2013 Zovegalisib First-in-Human Study <\/strong>\n <\/p>\n

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.<\/p>\n

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 fulvestrant or oral SERD), and 29% of patients (n=18) had detectable ESR1<\/em> mutations at baseline.<\/p>\n

\n Efficacy Consistent Across Subset Populations<\/strong>\n <\/p>\n

The data cut-off date was October 15, 2025 for this analysis. The total efficacy population consisted of 52 zovegalisib + fulvestrant patients who received 600mg BID fasted and did not have a PTEN or AKT co-mutation. Median follow-up was 20.2 months.<\/p>\n

The median progression free survival (PFS) was 10.3 months for all patients. Among the total of 31 patients with measurable disease, objective response rate (ORR) was 39%. For second line (2L) patients, median PFS was 11.4 months and ORR was 47%.<\/p>\n

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% (7\/16), and for patients who had a detectable ESR1<\/em> mutation at baseline, median PFS was 8.8 months and ORR was 60% (6\/10).<\/p>\n

The overall tolerability profile remained consistent with mutant-selective PI3K\u03b1 inhibition, with treatment-related adverse events that were mostly low-grade, manageable and reversible.<\/p>\n

\n Anticipated Zovegalisib Next Steps<\/strong>\n <\/p>\n