Relay Therapeutics’ Zovegalisib Receives Breakthrough Therapy Designation from U.S. FDA for Advanced Breast Cancer
Wednesday, February 04, 2026
Relay Therapeutics has received Breakthrough Therapy designation from the U.S. Food and Drug Administration for zovegalisib (RLY-2608) in combination with fulvestrant. The designation covers the treatment of adults with PIK3CA-mutant, hormone receptor-positive and HER2-negative locally advanced or metastatic breast cancer whose disease has returned or progressed after treatment with a CDK4/6 inhibitor.
The FDA granted the designation based on early clinical evidence suggesting that the zovegalisib and fulvestrant combination could offer meaningful benefit compared with available treatment options. Breakthrough Therapy designation is intended to speed up the development and review of medicines for serious conditions and provides closer guidance and interaction with the FDA.
Support for the designation came from data generated in the Phase 1/2 ReDiscover study. This trial is assessing the safety, tolerability, pharmacokinetics, pharmacodynamics and early anti-tumour activity of zovegalisib in combination with fulvestrant, and alongside fulvestrant and CDK inhibitors. The application included data across different PIK3CA mutation types and from two dosing schedules: 600 mg twice daily in a fasted state and 400 mg twice daily in a fed state, which is the dose being used in the ongoing Phase 3 ReDiscover-2 trial.
Safety and efficacy results from the 600 mg twice-daily fasted dose have been presented at major oncology meetings, including the 2025 American Society of Clinical Oncology Annual Meeting and the 2025 San Antonio Breast Cancer Symposium. Data from the 400 mg twice-daily fed dose are expected to be presented for the first time at the ESMO Targeted Anticancer Congress in March 2026.
Source: globenewswire.com
