Purpose: We performed a meta-analysis on the therapeutic effects of prostate-specific membrane antigen (PSMA)-617 labeled with lutetium-177 (Lu-PSMA-617) in patients with metastatic castration-resistant prostate cancer (mCRPC).
Patients and methods: The primary outcome was the therapeutic responses after the first cycle of Lu-PSMA-617 radioligand therapy. The parameters studied were the pooled proportions of any prostate-specific antigen (PSA) decline and a greater than 50% PSA decline. The secondary outcome was the survival effects after Lu-PSMA-617 radioligand therapy. Studied parameters were pooled hazard ratios of the overall survival according to any PSA decline and a greater than 50% PSA decline after the first cycle of Lu-PSMA-617 radioligand therapy.
Results: In total, 10 eligible studies with 455 patients were finally included in this meta-analysis. The pooled proportions of any PSA decline was 68.00% (95% confidence interval [CI], 63.55%-72.22%], and those with a greater than 50% PSA decline was 34.45% (95% CI, 30.14%-38.97%). The pooled hazard ratios for the overall survival of any PSA decline was 0.29 (95% CI, 0.21-0.40) with significance (P < 0.00001); however, a greater than 50% PSA decline was 0.82 (95% CI, 0.54-1.25) with no significance (P = 0.39).
Conclusions: We suggest that approximately two-thirds of any PSA decline and one-third of a greater than 50% PSA decline can be expected after the first cycle of Lu-PSMA-617 radioligand therapy in patients with mCRPC. Moreover, any PSA decline showed survival prolongation after the first cycle of the Lu-PSMA-617 radioligand therapy.