Oncologist and Patient Preferences for Attributes of CDK4/6 Inhibitor Regimens for the Treatment of Advanced/Metastatic HR Positive/HER2 Negative Breast Cancer: Discrete Choice Experiment and Best–Worst Scaling

PURPOSE: To understand and compare preferences for dosing- and toxicity-related attributes associated with selective cyclin-dependent 4/6 kinase inhibitors regimens among US oncologists and patients. MATERIALS AND METHODS: Oncologists and patients with mBC participated in an internet-based survey that included a discrete choice experiment (DCE) and a best–worst scaling (BWS) exercise. For the DCE, participants chose between two hypothetical treatment profiles, each with seven attributes: risk of dose reduction due to adverse events (AEs), risk of diarrhea, risk of abdominal pain, need for electrocardiogram (ECG) monitoring to assess heart function, risk of Grade 3/4 neutropenia, dosing regimen, and dosing schedule. The BWS exercise assessed the relative prioritization of a larger set of 16 attributes. Hierarchical Bayesian models were used to estimate preference weights for each attribute level. RESULTS: Oncologists (N=209) and patients (N=304) rated risks of diarrhea (25% each) and Grade 3/4 neutropenia (20% and 24%, respectively) as the most important attributes for treatment choice. The risks of diarrhea and Grade 3/4 neutropenia were 1.8 to 2.3 times (oncologists: 25% and 20%, respectively vs 11%) and 2.4 to 2.5 times (patients: 25% and 24%, respectively vs 10%) higher in relative importance than the risk of dose reduction due to AEs. Oncologists placed greater importance on the risk of dose reduction due to AEs and the need for ECG monitoring, whereas patients placed greater importance on the risk of Grade 3/4 neutropenia (all, p<0.05). The BWS exercise results were largely consistent with those from the DCE. CONCLUSION: The risks of diarrhea and Grade 3/4 neutropenia were key drivers of both oncologist and patient preferences. Overall, the palbociclib + aromatase inhibitor (AI) profile was most preferred, due to its association with a lower risk of diarrhea and no ECG monitoring, compared with abemaciclib + AI and ribociclib + AI profiles, respectively.