Final Overall Survival Results From nextMONARCH Trial in Metastatic Breast Cancer
Posted: Wednesday, December 2, 2020
Compared with abemaciclib monotherapy, the combination of tamoxifen with abemaciclib significantly improved overall survival for patients with hormone receptor–positive, HER2-negative metastatic breast cancer, according to the nextMONARCH trial, conducted by Erika P. Hamilton, MD, of the Sarah Cannon Research Institute, Nashville, and colleagues. The results of this multicenter, randomized, open-label study were presented during the European Society for Medical Oncology (ESMO) Virtual Congress 2020 (Abstract 273O).
The nextMONARCH trial involved patients with heavily pretreated hormone receptor–positive, HER2-negative metastatic breast cancer whose disease progressed on or after endocrine therapy and chemotherapy. Researchers examined the overall survival of patients continuously dosed with the CDK4/6 inhibitor abemaciclib with or without tamoxifen. A total of 234 patients were randomly assigned 1:1:1 to receive 150 mg of abemaciclib plus 20 mg of tamoxifen, 150 mg of abemaciclib alone, or 200 mg of abemaciclib plus prophylactic loperamide. Overall survival analysis took place 24 months after the final patient began treatment.
At the time of data cutoff, 12 patients were still on the study treatment. The median follow-up was 27.2 months. Median overall survival was 24.2 months with abemaciclib plus tamoxifen, 20.8 months with abemaciclib monotherapy, and 17.0 months with abemaciclib plus prophylactic loperamide arm. Adverse events occurred in at least 25% of patients across all abemaciclib arms; they included diarrhea (61.1%), neutropenia (49.6%), anemia (40.6%), nausea (36.3%), leukopenia (30.8%), fatigue (29.9%), and abdominal pain (27.4%). Progression-free survival results were comparable to the primary results of nextMONARCH, with no new safety findings reported.
According to Dr. Hamilton, these study findings suggest this combination therapy may prove to be an option for women with metastatic breast cancer who did not initially receive CDK4/6 inhibitors or those unable to tolerate endocrine therapy.
Disclosure: For full disclosures of the study authors, visit esmo.org.
