Endocrine Abstracts

Purpose: The purpose of this study was to evaluate the efficacy and safety of a novel theranostic agent, ¹⁷⁷Lu-DKFZ-PSMA-617 therapy in metastatic castration resistant prostate cancer (mCRPC).

Methods: 31 mCRPC patients with progressive disease despite second line hormonal therapy and/or Docetaxel chemotherapy were recruited for the study. All patients underwent diagnostic⁶⁸Ga-PSMA-HBED-CCPET/CT, prior to inclusion for therapy. Included patientsthen underwent quarterly ¹⁷⁷Lu-DKFZ-PSMA-617 therapy. Hematological, kidney function, liver function tests and serum PSA levels were recorded before and after therapy at 2 weeks, 4 weeks and 3 month intervals. Biochemical response was assessed with trend in serum PSA levels. Metabolic response was assessed by PERCIST 1 criteria. Clinical response was assessed by visual analogue score (VASmax) analgesic score (AS), Karanofskys performance status (KPS) and Toxicity and response criteria of the Eastern Cooperative Oncology Group (ECOG) criteria.

Results: The mean age of patients was 65.93±9.77 years (range: 38–81 years). The mean activity administered in the 31 patients was 5069±1845 MBqranging from 1–4 cycles. There was a decline in the mean serum PSA levels from the baseline (baseline: 275 ng/ml, post 1st cycle therapy: 141.75 ng/ml). Based on biochemical response criteria 2/31, 20/31, 3/21 and 6/31 had complete response (CR), partial response (PR), stable disease (SD) and progressive disease (PD), respectively. Metabolic response revealed 2/6 patients with CR, and remaining 3/6 patients with PR and 1/6 patients with SD. The mean VASmax score decreased from 7.5 to 3. The mean analgesic score reduced from 2.5 to 1.8 after therapy. The mean KPS score improved from 50.32 to 65.42 after therapies. The mean ECOG performance status improved from 2.54 to 1.78 after therapy. Two patients experienced grade I and grade II hemoglobin toxicity each.None of the patients experienced nephrotoxicity or hepatotoxicity.

Conclusion: ¹⁷⁷Lu-DKFZ-PSMA-617 radionuclide therapy is a safe and effective approach in the treatment of mCRPC patients.