Five-year follow-up of adjuvant abemaciclib with endocrine therapy for HR+ HER2- high-risk early breast cancer in monarchE

The multinational phase 3 monarchE trial randomized 5636 patients with HR-positive, HER2-negative, high-risk early-stage breast cancer (EBC) to endocrine therapy with or without two years of abemaciclib (CDK4/6 inhibitor). The primary analysis showed improved invasive disease-free survival (IDFS) and distant relapse-free survival (DRFS). Updated results of the trial have now been published. The figure shows that with a median follow-up of 54 months the benefit of abemaciclib was sustained for IDFS and DRFS, resulting in continuous reduction of the risk of developing invasive and distant disease recurrence beyond the completion of treatment. The authors conclude that the increasing absolute improvement at 5 years is consistent with a carryover effect and further supports the use of abemaciclib in patients with high-risk EBC.