Efficacy of abemaciclib, palbociclib and ribociclib among the older compared with younger women in HR-positive/HER2-negative, advanced breast cancer.

e13043Background: The inhibition of cyclin-dependent kinases 4 and 6 (CDK4/6) could potentially overcome or delay resistance to endocrine therapy in advanced breast cancer that is positive for hormone receptor and negative for human epidermal growth factor receptor 2 (HER2). To our knowledge, there are few studies comparing the benefit of CDK4/6 inhibitors in advanced breast cancer among elderly or younger patients. Methods: The search was conducted in PubMed, ASCO, ESMO and SABCS meeting abstract databases. We identified phase 2 or 3 trials recruiting patients with breast cancer, randomized to receive hormonal treatment (HT) plus either CDK4/6 inhibitors or placebo. The primary end point was PFS. We performed two distinct Meta-Analyses (MAs); one among the older and the other among the younger patients. Hazard Ratios (HRs) with their 95% confidence intervals (CIs) were collected from the studies and pooled to compare the CDK4/6 effect among elderly and younger patients. Results: This MA included 7 studie...