Phase 1 study of darolutamide (ODM-201): a new-generation androgen receptor antagonist, in Japanese patients with metastatic castration-resistant prostate cancer

PURPOSE: This trial assessed the safety, pharmacokinetics, and efficacy of darolutamide (ODM-201), a new-generation nonsteroidal androgen receptor antagonist, in Japanese patients with metastatic castration-resistant prostate cancer (mCRPC). METHODS: In this open-label, nonrandomized, two-cohort, dose-escalating phase 1 study, Japanese patients with mCRPC were enrolled after a screening period. In the single-dose period (≈1 week), darolutamide was administered at 300 mg (Cohort 1) or 600 mg (Cohort 2) on day −5 (fasting state) and day −2 (fed condition). In the subsequent multiple-dose period (fed condition), patients received darolutamide 300 mg twice daily (Cohort 1) or 600 mg twice daily (Cohort 2) for 12 weeks. Primary endpoints: evaluate safety and pharmacokinetics of darolutamide. RESULTS: Of 12 patients enrolled, 9 received darolutamide (Cohort 1, n = 3; Cohort 2, n = 6). All 9 patients experienced ≥1 treatment-emergent adverse event (TEAE; majority Grade 1/2). Incidence of drug-related TEAEs (DR-TEAEs) was 44% (all grades; n = 4); most common DR-TEAE was decreased appetite (22%), and 1 serious DR-TEAE (Grade 3 nausea) was observed. No Grade ≥4 DR-TEAEs or new safety signals were observed. C (max) and AUC (0–t (last)) were dose-dependent; pharmacokinetics of each dose appeared to be linear over time. Prostate-specific antigen response was observed in 11% (1/9) of patients. Compared with fasting status, geometric mean C (max) increased 2.5-fold after 300 mg and 2.8-fold after 600 mg; geometric mean AUC (0–t (last)) increased 2.5-fold after both doses under fed conditions. CONCLUSIONS: Darolutamide was well tolerated at the examined doses in Japanese patients with mCRPC, without differences in safety and pharmacokinetics relative to Western patients. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00280-017-3417-3) contains supplementary material, which is available to authorized users.