Phase 2 and 3 Study of LY4064809 with CDK46 Inhibitor and Endocrine Therapy for Adults with Advanced HR, HER2- Breast Cancer Having a PIK3CA Mutation

What this Trial Is About

Researchers are evaluating the addition of Tersolisib LY4064809STX-478 to other anti-cancer drugs as a first treatment for adults with advanced hormone receptor-positive HRhuman epidermal growth factor receptor 2-negative HER2- breast cancer that has a PIK3CA mutation. This Phase 3 randomized, double-blind, placebo-controlled trial aims to understand the efficacy and safety of this combination compared to placebo, focusing on improving outcomes for patients with this specific genetic change. Participants receive LY4064809 orally in one of two doses combined with a CDK46 inhibitor such as Ribociclib, Palbociclib, or Abemaciclib and endocrine therapy ET administered orally or via intramuscular injection. The comparison group receives a placebo combined with the same CDK46 inhibitor and ET. The study includes two parts Part 1 explores dose optimization, and Part 2 evaluates the treatment combinations effectiveness and safety as a first-line therapy. During the study, participants will have regular assessments to monitor cancer response, progression, and safety over an estimated period of up to 5 years or more. Researchers will measure outcomes such as overall response rate, progression-free survival, duration of response, overall survival, and quality of life. Treatment continues as long as the cancer benefits without intolerable side effects. Safety monitoring, laboratory tests, and quality of life questionnaires are part of the participant involvement throughout the trial.

A Study of Tersolisib (LY4064809/STX-478) With Other Anti-Cancer Treatments in Participants With Advanced Breast Cancer With a Genetic Change (PIK3CA)