Phase 3 Study Comparing Palazestrant OP-1250 to Standard Endocrine Treatments for ER, HER2- Advanced or Metastatic Breast Cancer After Endocrine and CDK46 Inhibitor Therapy

What this Trial Is About

Researchers are evaluating palazestrant OP-1250 compared to standard endocrine therapies for adults with ER-positive, HER2-negative advanced or metastatic breast cancer that has progressed after endocrine therapy combined with a CDK46 inhibitor. This international phase 3 trial aims to assess the safety and effectiveness of palazestrant versus fulvestrant or aromatase inhibitors such as anastrozole, letrozole, or exemestane. Participants are randomly assigned to receive either palazestrant daily on a 28-day cycle at doses of 90 mg or 120 mg during the dose-selection phase, or the standard-of-care endocrine therapy including fulvestrant administered on specific days or one of the aromatase inhibitors given daily on similar cycles. The trial includes an initial dose-selection period with about 120 participants, followed by a larger randomized phase with approximately 390 participants receiving the selected dose of palazestrant or standard treatment. Throughout the study, participants will be monitored for adverse events, dose adjustments, and drug discontinuations up to 16 weeks. Researchers will measure progression-free survival for up to two years and overall survival for up to four years after randomization. Regular assessments will include clinical evaluations and safety monitoring to observe the effects and tolerability of the treatments during the trial.

OP-1250 (Palazestrant) vs. Standard of Care for the Treatment of ER+/HER2- Advanced Breast Cancer