Three novel AR inhibitors (darolutamide (DAR), apalutamide (APA), and enzalutamide (ENZ)) for nonmetastatic castration-resistant prostate cancer (nmCRPC) all prolong metastasis-free survival (MFS) by approximately 2 years, and their therapeutic efficacy is considered equivalent. In this study, we retrospectively evaluated nmCRPC patients who were prescribed DAR at Showa University Hospital.

The subjects were 25 nmCRPC patients who were prescribed DAR from January 2020 to March 2025. Patient background, course of treatment, and safety were investigated retrospectively.

The median age at diagnosis was 74 years, the median age at initiation of taking DAR was 79 years, and the median PSA at nmCRPC diagnosis was 16.3 ng/ml. Gleason Score 6/7/8/9/ was 4/3/4/11 at diagnosis (unknown in 3 cases), and Stage A/B/C/D were 1/12/3/8 (unknown in 1 cases). The median time on DAR was 15 months, median time to CRPC was 96 months, and PSA doubling time (PSADT) was 6.5 months. Adverse events were hot flashes in one case, dizziness in one case, hypertension in one case, liver dysfunction in one case, numbness in lower limbs in one case, and respiratory distress in one case, none of which were serious.

Because of the short observation period, there were no cases of apparent progression of the disease, but the adverse events were minor and the drug was considered to be well tolerated. Further investigation including overall survival over a long observation period is needed.