DARO is a structurally distinct androgen receptor antagonist for which in vitro and phase 1/2 studies suggest low risk of adverse events (AEs) and drug–drug interaction. In the ARAMIS study of DARO in nmCRPC, metastasis-free survival (MFS) was significantly prolonged vs placebo (PBO) (40.4 vs 18.4 mo; hazard ratio [HR] 0.41; 95% confidence interval [CI] 0.34–0.50; P < 0.001) and interim overall survival (OS) favored DARO (HR 0.71; 95% CI 0.50–0.99; P = 0.045).
1509 pts were randomized 2:1 to DARO 600 mg (two 300 mg tablets) twice daily (n = 955) or PBO (n = 554) while continuing androgen deprivation therapy (ADT). Primary endpoint was MFS. Secondary endpoints included OS and time to pain progression (assessed by Brief Pain Inventory Short Form). QoL was assessed by European Organisation for Research and Treatment of Cancer QoL Prostate Cancer module (EORTC-QLQ-PR25) at baseline (BL) and every 16 wks until end of treatment. Analysis of time to deterioration in EORTC-QLQ-PR25 subscales, defined as first occurrence of a minimally important difference (half the standard deviation of BL value), used Kaplan–Meier estimators and stratified Cox proportional hazard models.
DARO significantly delayed pain progression vs PBO (40.3 vs 25.4 mo; HR 0.65; 95% CI 0.53–0.79; P < 0.001); this was maintained beyond end of study treatment. Time to deterioration of EORTC-QLQ-PR25 outcomes showed statistically and clinically significant delays with DARO vs PBO for urinary symptoms (25.8 vs 14.8 mo; HR 0.64; 95% CI 0.54–0.76; P < 0.01). Time to deterioration of hormonal treatment-related symptoms was comparable with DARO vs PBO (18.9 vs 18.4 mo; HR 1.06; 95% CI 0.88–1.27; P = 0.52). DARO was well tolerated. Exposure-adjusted incidences (pts per 100 years’ exposure) of AEs of interest were similar/lower with DARO vs PBO (fatigue/asthenic conditions [11.3 vs 11.1], hypertension [4.7 vs 5.1], hot flush [3.7 vs 4.1], fracture [3.0 vs 3.5], falls [2.7 vs 4.1], cognitive disorder [0.3 vs 0.2], and seizure [0.2 vs 0.2]).
For nmCRPC pts, DARO prolongs MFS, is well tolerated, maintains QoL, and delays worsening of pain and disease-related symptoms compared with PBO. Clinical trial information: NCT02200614