Quality of life with ribociclib versus abemaciclib as first-line treatment of HR+/HER2− advanced breast cancer: a matching-adjusted indirect comparison

Abstract

Background: A cyclin-dependent kinase 4/6 inhibitor (CDK4/6i) + endocrine therapy is recommended as first-line treatment for hormone receptor-positive/human epidermal growth factor receptor 2-negative (HR+/HER2−) advanced breast cancer (ABC). Quality of life (QoL) is an important endpoint that affects treatment decisions. Understanding the relevance of CDK4/6i treatment on QoL is gaining importance given use in earlier treatment lines for ABC and an emerging role in treating early breast cancer in which QoL may be more impactful. In the absence of head-to-head trial data, a matching-adjusted indirect comparison (MAIC) permits comparative efficacy between trials. Objective: In this analysis, patient-reported QoL for MONALEESA-2 [ribociclib + aromatase inhibitor (AI)] and MONARCH 3 (abemaciclib + AI) was compared using MAIC with a focus on individual domains. Design: An anchored MAIC of QoL comparing ribociclib + AI versus abemaciclib + AI was performed using data from the European Organization for Research and Treatment of Cancer quality of life questionnaire (QLQ)-C30 and BR-23 questionnaires. Methods: Individual patient data from MONALEESA-2 and published aggregated data from MONARCH 3 were included in this analysis. Time to sustained deterioration (TTSD) was calculated as the time from randomization to a ⩾10-point deterioration with no later improvement above this threshold. Results: Patients from the ribociclib ( n = 205) and placebo ( n = 149) arms of MONALEESA-2 were matched with patients from the abemaciclib ( n = 328) and placebo ( n = 165) arms of MONARCH 3. After weighting, baseline patient characteristics were well balanced. TTSD significantly favored ribociclib versus abemaciclib in appetite loss [hazard ratio (HR), 0.46; 95% confidence interval (CI), 0.27–0.81], diarrhea (HR, 0.42; 95% CI, 0.23–0.79), fatigue (HR, 0.63; 95% CI, 0.41–0.96), and arm symptoms (HR, 0.49; 95% CI, 0.30–0.79). TTSD did not significantly favor abemaciclib compared with ribociclib in any functional or symptom scale of the QLQ-C30 or BR-23 questionnaires. Conclusions: This MAIC indicates that ribociclib + AI is associated with better symptom-related QoL than abemaciclib + AI for postmenopausal patients with HR+/HER2− ABC treated in the first-line setting. Trial registration: NCT01958021 (MONALEESA-2) and NCT02246621 (MONARCH 3)