Relay Therapeutics (NASDAQ:RLAY) announced on Monday that it will advance its lead candidate, zovegalisib, into a planned Phase 3 frontline trial for the treatment of PIK3CA-mutated, HR+/HER2- metastatic breast cancer.
The company aims to initiate the pivotal study in early 2027, pending final regulatory feedback.
The decision is supported by new clinical data showing a 44% objective response rate (ORR) among 34 measurable patients in a median third-line setting.
The data highlights the drug's potential efficacy in a population that has already undergone multiple prior therapies.
Safety profiles indicated a 3% discontinuation rate for zovegalisib, though the study noted a 40% rate of Grade 3 or higher treatment-related adverse events (TRAEs).
The upcoming Phase 3 trial will utilize a combination therapy approach.
Under a supply agreement, Pfizer will provide atirmociclib to be used alongside zovegalisib.
Relay also disclosed a pharmacokinetic interaction that increases zovegalisib exposure approximately 2.5-fold, a factor that will likely inform dosing strategies in the upcoming late-stage study.