Abstract
BACKGROUND: Patient-reported outcome (PRO) measures can provide valuable information in evaluating patients' health-related quality of life (HRQoL). Post hoc analysis of the AFTERCAB study was conducted to evaluate the HRQoL benefit of enzalutamide plus androgen deprivation therapy (ADT) compared to flutamide plus ADT for the treatment of patients with castration-resistant prostate cancer (CRPC) in Japan. METHODS: The open-label AFTERCAB study was conducted from November 2016 to March 2020 in Japanese men aged ≥ 20 years with asymptomatic or mildly symptomatic CRPC. Patients received enzalutamide plus ADT or flutamide plus ADT, respectively, as first-line alternative androgen therapy (AAT). HRQoL was analyzed through the Functional Assessment of Cancer Therapy-Prostate, EuroQoL 5-Dimension 5-Level instruments, Brief Pain Inventory-Short Form, and Brief Fatigue Inventory. The longitudinal changes in HRQoL, HRQoL deterioration based on minimally important difference (MID), and time to HRQoL deterioration were evaluated for first-line AAT. RESULTS: Overall, HRQoL between the enzalutamide and flutamide groups was similar during first-line treatment. No statistically significant HRQoL difference in change from baseline to week 61 (least square mean difference; p value) was observed. Furthermore, proportions of pain progression, symptom worsening, and HRQoL deterioration based on MID, were not significantly different between groups. CONCLUSIONS: The results were similar in all subscales of each PRO, demonstrating similar HRQoL deterioration based on MID criteria between the enzalutamide and flutamide groups.