PSMA Radioligand Therapy Efficacy in Heavily pretreated mCRPC patients Treated at King Hussein Cancer Center in Jordan: a glimpse of theranostics in the Arab World

Introduction: This analysis aims to assess the efficacy and safety of 177Lu-PSMA-617 in the mCRPC patients who received this targeted radioligand therapy at teritary cancer center in Jordan by examining the biochemical response, quality of life, and toxicity profile,

Methods: Patients who had at least one PRLT cycle undergone were included. After receiving the best available standard of care, 42 consecutive mCRPC patients who progressed received 132 cycles of Lu-177 PSMA. Average number of prior treatments: 4 (range: 2-6). All of the patients had previously taken abiraterone or enzalutamide; 28 had taken both; 9 had taken abiraterone only; 4 had taken enzalutamide only; 30 had taken one agent of chemotherapy; 4 had taken two or more agents; and the remaining 7 had not. 29 patients also received radiotherapy. Before receiving Lu-177 PSMA therapy, PSA tests were performed on each patient. Patients received doses of Lu-177 PSMA (4–7.4 GBq) at intervals of 6–8 weeks. Nine cycles were administered to one patient, seven cycles to another, two cycles to two patients, four cycles to ten patients, three cycles to eight patients, two cycles to ten patients, and one cycle to eight patients. After each cycle, the PSA response was assessed for at least two weeks. A PSA decline of 50% was regarded as a response in accordance with the Prostate Cancer Workgroup 3 Criteria. The Common Toxicity Criteria for Adverse Events were used to classify toxicity based on blood levels. Each patient's quality of life with regard to pain was evaluated.

Results: After the first cycle, 33 out of 40 patients (82.5%) showed a PSA decline of any magnitude. After the last cycle, (40%) and (60%) of patients, respectively, experienced a decline in PSA of 50% and of any amount. No patient experienced hepatotoxicity or nephrotoxicity grade 3–4. 40 patients (96%) said their pain had significantly decreased.

Conclusions: Lu-177 PSMA produced a significant biochemical response in heavily pretreated mCRPC, significantly reduced pain, and had a favorable toxicity profile. During PRLT, the serum PSA level is still a clinically significant predictor of response. In the following stage of this project, the overall survival of those patients will be examined in light of the biochemical response.