Phase 3 Study Comparing BGB-43395 Plus Letrozole to CDK46 Inhibitors Plus Letrozole in Adults With Advanced or Metastatic HRHER2- Breast Cancer Without Prior Treatment for Advanced Disease

What this Trial Is About

Researchers are evaluating the efficacy and safety of BGB-43395 combined with letrozole compared to an investigators choice of cyclin-dependent kinase 46 inhibitors CDK46i combined with letrozole in patients who have advanced or metastatic hormone receptor positive HR and human epidermal growth factor receptor 2 negative HER2- breast cancer. This study focuses on patients who have not received prior systemic treatment for their advanced or metastatic disease. The trial is a phase 3, open-label, randomized study sponsored by BeOne Medicines. Participants will be randomly assigned to one of two treatment groups. One group will receive oral BGB-43395 plus letrozole, while the other group will receive one of the CDK46 inhibitors abemaciclib, palbociclib, or ribociclib combined with letrozole, both administered orally. Treatments will be given according to the investigators choice for the comparator group. The studys primary treatment period is expected to last up to approximately 4 years for progression-free survival assessment, with follow-up extending up to approximately 11 years for overall survival and safety monitoring. During the study, participants will attend regular visits for treatment administration and monitoring. Researchers will assess progression-free survival as the primary outcome, with additional measures including overall survival, response rates, duration of response, clinical benefit, and safety assessments. Quality of life will be evaluated using the European Organisation for Research and Treatment of Cancer EORTC questionnaires. Safety will be monitored from the first dose until 30 days after the last dose, with long-term follow-up lasting up to approximately 11 years. Total participation duration may extend over this period depending on individual outcomes and monitoring requirements.

BGB-43395 Plus Letrozole Versus CDK4/6i Plus Letrozole for Patients With Advanced or Metastatic HR+/HER2- Breast Cancer Who Have Not Received Prior Treatment for Advanced or Metastatic Disease