Podium Session 1: Prostate Cancer June 26, 2016 1050–1150

ABSTRACT: Introduction and Objectives: The phase 2 TERRAIN trial compared the efficacy and safety of enzalutamide (ENZA) vs. bicalutamide (BIC) in patients (pts) with metastatic castration-resistant prostate cancer who had progressed on luteinizing hormone-releasing hormone agonist/antagonist therapy or after bilateral orchiectomy while maintaining castration therapy during the study. An age effect analysis was pre-specified to investigate the efficacy and safety of ENZA vs. BIC. Results are presented in younger (<75 years) and older (?75 years) pts in the TERRAIN population. Methods: In this double-blind study in North America and Europe, pts were randomized 1:1 to ENZA 160 mg/day or BIC 50 mg/day. The primary efficacy endpoint was centrally assessed progression-free survival (PFS) and a secondary efficacy endpoint was time to prostate-specific antigen (PSA) progression. Results: 184 pts were randomized to ENZA and 191 pts to BIC. 126 (68.5%) and 119 (62.3%) pts were <75, and 58 (31.5%) and 72 (37.7%) pts were ?75, in the ENZA and BIC arms, respectively. PFS was significantly improved with ENZA vs. BIC in pts <75 years (median 16.6 vs. 5.8 months; HR 0.38 (95% CI 0.27, 0.52) and pts ?75 years (median 13.8 vs. 6.4 months; HR 0.59 (95% CI 0.37, 0.92). Median time to PSA progression was similarly significantly improved with ENZA vs. BIC in younger (median 22.1 vs. 8.2 months; HR 0.27 (95% CI 0.18, 0.40) and older pts (median 16.6 vs. 5.8 months; HR 0.33 (95% CI 0.19, 0.57). Adverse events (AEs) with ENZA were more frequent in older pts (98.3%) vs. younger pts (92.8%), but a similar distribution of treatment-related AEs between treatment arms was observed in either age group. Conclusions: ENZA had greater efficacy than BIC regardless of age, with superior PFS and time to PSA progression. ENZA showed safety consistent with its known safety profile in both age subgroups.

SUBMITTER: Siemens D 

PROVIDER: S-EPMC5413364 | biostudies-literature | 2016 Jan

REPOSITORIES: biostudies-literature