On March 16, 2026, Relay Therapeutics, Inc. (Nasdaq: RLAY) announced significant findings from the Phase 1/2 ReDiscover trial of zovegalisib (RLY-2608) in combination with fulvestrant, targeting patients with PI3Kα-mutated, HR+/HER2- metastatic breast cancer. The trial results were presented at the European Society for Medical Oncology (ESMO) Targeted Anticancer Therapies Congress 2026 in Paris, France. The data revealed that the recommended Phase 3 dose of 400mg twice daily (BID) taken with food demonstrated a median progression-free survival (PFS) of 11.1 months, with a notable 43% confirmed objective response rate (ORR) among patients with measurable disease. The trial included 60 patients, all of whom had previously received a CDK4/6 inhibitor and at least one prior endocrine therapy in the advanced setting. Pharmacokinetic analyses indicated that the 400mg BID fed regimen achieved comparable exposure levels to the previously evaluated 600mg BID fasted dose, suggesting effective dosing strategies for future trials. The safety profile was consistent with earlier studies, primarily showing low-grade, manageable, and reversible treatment-related adverse events. Relay Therapeutics is advancing zovegalisib into the ongoing Phase 3 ReDiscover-2 trial, which has received FDA Breakthrough Therapy designation, further emphasizing the potential of this treatment in addressing unmet needs in breast cancer therapy.

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