Comparative real-world study of apalutamide and darolutamide in Japanese patients with non-metastatic castration-resistant prostate cancer.

Background: Non-metastatic castration-resistant prostate cancer (nmCRPC) is often asymptomatic but carries a risk of progression to metastatic disease. Apalutamide (APA) and darolutamide (DARO) have been shown to improve metastasis-free survival (MFS). This study evaluated the real-world efficacy and safety of APA and DARO in Japanese patients with nmCRPC.

Methods: We retrospectively analyzed 67 nmCRPC patients treated with APA (n = 32) or DARO (n = 35). Outcomes included time to treatment discontinuation or mCRPC progression, time to mCRPC, PSA response rate, treatment-related adverse events (TRAEs), post-mCRPC treatment patterns, and predictors of progression.

Results: In patients with prostate-specific antigen doubling time (PSADT) < 10 months, no significant difference was observed between the APA and DARO groups in the time to progression to mCRPC. PSA response and MFS were comparable between groups. TRAEs were significantly more frequent with APA (75.0% vs. 25.7%), with rash being the most common. High PSA at treatment initiation (≥ 3.6 ng/mL) and PSA response < 90% were independent predictors of progression. Abiraterone was the most common first-line agent after mCRPC.

Conclusions: DARO was associated with a lower incidence of TRAEs compared to APA. Rash was more prevalent with APA. Elevated baseline PSA and suboptimal PSA response were associated with progression.