Baicheng

Researchers are investigating the combination of lasofoxifene and abemaciclib compared to fulvestrant and abemaciclib to treat women and men with locally advanced or metastatic estrogen receptor positive (ER+) and human epidermal growth factor receptor 2 negative (HER2-) breast cancer that has an ESR1 mutation. This phase 3 study includes patients who have previously received treatment with ribociclib or palbociclib and aims to evaluate the effectiveness, safety, and tolerability of these treatment combinations. Participants will be randomly assigned to receive either oral lasofoxifene at 5 mg daily combined with oral abemaciclib 150 mg twice a day, or intramuscular fulvestrant 500 mg on specific days followed by monthly doses plus oral abemaciclib 150 mg twice daily. The treatment schedules are designed to compare how well these combinations work in managing the cancer. During the study, participants will be closely monitored for progression-free survival over approximately three years. Researchers will assess the cancer's response to treatment, track any side effects, and evaluate safety and tolerability. Regular evaluations and follow-ups will ensure comprehensive data collection to understand the impact of these therapies on advanced breast cancer.