Patient-reported outcomes (PROs) among men receiving talazoparib (TALA) + enzalutamide (ENZA) vs placebo (PBO) + ENZA as first-line (1L) treatment for metastatic castration-resistant prostate cancer (mCRPC): Results from a phase 3 study (TALAPRO-2).

Abstract

5013 Background: TALAPRO-2 (NCT03395197) showed statistically significant improvement in radiographic progression free survival with TALA + ENZA (n=402) vs PBO + ENZA (n=403) (HR=0.63 95% CI 0.51-0.78; P<0.001) in men receiving 1L treatment for mCRPC. Here we report PRO endpoints from TALAPRO-2. Methods: PROs were assessed at day 1 (baseline) and at scheduled visits until radiographic progression (every 4 weeks until week 53, and then every 8 weeks) using the EORTC QLQ-C30 and its prostate cancer module, QLQ-PR25. Prespecified PRO analyses included overall mean change from baseline (per longitudinal repeated measures mixed-effects model) and time to definitive clinically meaningful (≥10-point change) deterioration (TTD). Between-arm comparisons of TTD were made using a stratified log-rank test and a Cox proportional hazards model. Results: Of the 805 men randomized and treated, 793 had a baseline score followed by at least 1 post-baseline score; TALA + ENZA (n=395), PBO + ENZA (n=398). Although the treatment effect on global health status (GHS)/quality of life (QoL) significantly favored PBO + ENZA, the predefined threshold of clinical meaningfulness was not met; moreover, no significant differences between the arms were observed in any functioning scales. A significantly longer TTD in GHS/QoL was observed for TALA + ENZA; HR=0.780 (95% CI: 0.62, 0.99), P=0.038; median: 30.8 months vs 25.0 months. A numerical greater delay in TTD in urinary symptoms was longer for TALA + ENZA; HR=0.759 (95% CI: 0.543, 1.061), P=0.105; median not reached vs 35.9 months. Additional PRO results will be presented. Conclusions: Compared with PBO + ENZA, in the TALA + ENZA arm there was 1) a modest deterioration disfavoring GHS/QoL (deterioration was not clinically meaningful based on the predefined threshold), and 2) a maintenance in all functioning scales. TTD in GHS/QoL was significantly longer with TALA + ENZA vs PBO + ENZA, reflecting improved disease control. These results complement the benefit-risk assessment of TALAPRO-2. Clinical trial information: NCT03395197 . [Table: see text]