Is 177 Lu-PSMA an effective treatment modality for mCRPC patients with bone and visceral metastasis?

Objective We analyzed the clinical outcome of lutetium-177 prostate-specific membrane antigen (177Lu-PSMA) in metastatic castration-resistant prostate cancer (mCRPC) patients with visceral metastasis. Subjects and methods Ten patients of mCRPC with visceral metastasis were enrolled for one cycle of 177Lu-PSMA therapy. Number of efficacy and safety parameters, e.g., prostate-specific antigen (PSA), visual analog scale (VAS) and analgesic quantification scale (AQS), hemoglobin (Hb), total leukocytes counts (TLC), platelets, creatinine, & total bilirubin, were assessed and compared with Wilcoxon signed-rank test. The progression-free survival (PFS) curve was computed by the Kaplan-Meier method. The receiver operating characteristic curve (ROC) was also plotted for 177Lu-PSMA dose. P≤0.05 was considered significant. Results Liver (80%), lung (30%), adrenal (10%), and peritoneum (10%) were the sites of visceral metastasis in our study. On PSA response assessment, 10%, 60%, and 30% of the patients had partial response, stable disease, and progressive disease, respectively. Forty percent of the patients had improvement in the VAS, while 50% had improvement in the AQS score. Median PFS was 24 weeks in our study. A cut-off of 4.88GBq of 177Lu-PSMA was the best-predicted progression with 66.67% sensitivity and 100% specificity on ROC analysis. Thirty percent of the patients showed grade 3 anemia. No other significant toxicity was seen. Conclusion Lutetium-177-PSMA was a reasonable palliative treatment option with limited toxicity for these end-stage mCRPC patients with visceral metastasis with adequate PSA stabilization. A synergistic drug amalgamation may be an ideal way to boost the outcome in the future.