Radioligand Therapy With 177Lu-PSMA-617 as A Novel Therapeutic Option in Patients With Metastatic Castration Resistant Prostate Cancer

Background: Despite progress in treatment of metastatic castration-resistant prostate cancer (mCRPC), new approaches are urgently needed. Recently theranostic concepts using radiolabeled ligands of the prostate-specific membrane antigen (PSMA) have been developed for diagnostics and therapy of patients with advanced mCRPC. The aim of this study was to evaluate tumor response, adverse effects, and survival in patients undergoing radioligand therapy with Lu-177-PSMA-617. Methods: Fifty therapies using Lu-177-PSMA-617 were performed in 28 consecutive patients with mCRPC and exhausted conventional therapeutic options (median age, 73.4 years; range, 45-87 years). Data were retrospectively analyzed with focus on response, safety, and survival. The median overall survival was compared with that of a recent historical patient cohort treated with best supportive care prior to availability of Lu-177-PSMA-617. Results: Any PSA decline occurred in 59% and 75% of patients after 1 and 2 therapies. Moreover, a PSA decline of 50% or greater occurred in 32% and 50%. Therapies were well tolerated. Hematologic and renal parameters changed insignificantly; permanent xerostomia or other safetyrelated toxicity did not occur. The estimated median survival was 29.4 weeks, significantly longer than survival in the historical best supportive care group (19.7 weeks [hazard ratio, 0.44; 95% confidence interval, 0.20-0.95]; P = 0.031). Conclusions: Results from 50 therapies show that radioligand therapy with Lu-177-PSMA-617 is effective and well tolerated and seems to increase overall survival. A future randomized controlled prospective study will be necessary to confirm these results.