Study Finds Differing Effectiveness of CDK4/6 Inhibitors in Advanced Breast Cancer

A recent multicenter study has revealed varying effectiveness among three CDK4/6 inhibitors—abemaciclib, palbociclib, and ribociclib—in treating advanced hormone receptor-positive, HER2-negative breast cancer. The research, published in the Annals of Oncology, analyzed real-world progression-free survival (rwPFS) outcomes over a median follow-up of approximately 34 months. Findings indicated that patients receiving abemaciclib or ribociclib experienced significantly longer periods without disease progression compared to those treated with palbociclib. Specifically, the adjusted hazard ratios favored abemaciclib (HR 0.76) and ribociclib (HR 0.83) over palbociclib, with no notable difference observed between the two drugs. Further subgroup analysis showed that abemaciclib alone improved rwPFS in endocrine-sensitive cases. In premenopausal women or those with endocrine-resistant or luminal B-like disease, both abemaciclib and ribociclib outperformed palbociclib. Additionally, abemaciclib demonstrated superior efficacy in patients with de novo metastatic disease and poorer performance status. All three medications showed similar effectiveness in patients with bone-only metastases. T...