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 and AUC (0-t ) 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 increased 2.5-fold after 300 mg and 2.8-fold after 600 mg; geometric mean AUC (0-t ) 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.