Effect of enzalutamide on health-related quality of life (HRQoL) in men with metastatic castration-resistant prostate cancer (mCRPC) following docetaxel-based therapy: Results from the AFFIRM study.

Abstract

17 Background: In the AFFIRM trial, enzalutamide (ENZ), an oral androgen receptor inhibitor, was superior to placebo (PBO) in overall survival (HR=0.63 [0.53, 0.75], p<0.001) [Scher et al. NEJM 2012;367:1187]. This analysis focuses on impact of ENZ on HRQoL. Methods: Men with mCRPC previously treated with docetaxel were randomized (2:1) to receive ENZ (160mg/day) or PBO. HRQoL was assessed at baseline (BL), weeks 13, 17, 21, 25 and every subsequent 12 weeks using the Functional Assessment of Cancer Therapy-Prostate (FACT-P) questionnaire. Patients with BL and ≥1 post-BL evaluable forms were included in this analysis. Change from BL in FACT-P scores over 25 weeks of treatment was analyzed using linear mixed models. HRQoL improvement/deterioration was defined as a 10-point or higher increase/decrease during the study compared to BL on the FACT-P total score. Results: The HRQoL analysis included 938 patients. Changes from BL in FACT-P total score and domains over 25 weeks of treatment were significantly smaller (less decline) with ENZ than PBO (Table). A greater percentage of patients on ENZ reported HRQoL improvement compared to PBO (42.2% vs 14.5%; p<0.001). Median time to first HRQoL deterioration was 9.0 months for ENZ and 3.7 months for PBO (p<0.001). Overall, 46.8% of patients on ENZ and 59.3% on PBO experienced HRQoL deterioration at some point while on treatment (p=0.001). Conclusions: Compared to PBO, therapy with ENZ yields significantly better HRQoL across all domains and delays deterioration. The extent of the HRQoL advantage, along with the previously established overall survival gain of ENZ over PBO, suggest that ENZ confers a significant and meaningful clinical benefit to men with mCRPC. [Table: see text]