Real-world outcomes of prostate-specific membrane antigen-targeted radioligand therapy in Japanese patients with metastatic castration-resistant prostate cancer.

PURPOSE: Prostate-specific membrane antigen radioligand therapy (PSMA RLT) improves survival in metastatic castration-resistant prostate cancer (mCRPC). However, evidence in Japanese cohorts is limited. We evaluated the safety and efficacy of PSMA RLT in Japanese patients with mCRPC.

MATERIALS AND

METHODS

We retrospectively analyzed 82 Japanese patients with mCRPC treated with PSMA RLT between 2018 and 2024 in Australia. PSMA RLT included Lutetium-177, Actinium-225, or Terbium-161 conjugated PSMA ligands, following PSMA Positron Emission Tomography / Computed Tomography confirmation of target expression. Endpoints were prostate-specific antigen (PSA) response (≥50% decline), progression-free survival (PFS), overall survival (OS), and treatment-related adverse events (TrAEs). Cox proportional hazards regression identified prognostic factors for survival.

RESULTS

Thirty-one patients (38%) achieved a PSA response. Median PFS and OS were 4 and 20 months, respectively. While no significant difference was observed in >50% PSA decline, >80% decline was significantly higher in chemo-naïve patients (43% vs. 7.4%, P < .001), with longer PFS (8 vs. 3 months, P = .006) and OS (not reached vs. 11 months, P < .001). On multivariable analysis, poorer performance status and prior chemotherapy were independent factors for worse OS. TrAEs of any grade occurred in 49 patients (60%), most commonly fatigue. Grade ≥ 3 TrAEs occurred in 15%, with no treatment-related deaths.

CONCLUSION

PSMA RLT provided meaningful clinical benefit with favorable tolerability in Japanese patients with mCRPC, especially those without prior chemotherapy. Early integration of PSMA RLT may offer additional therapeutic advantages.