Treatment outcome and identification of factors influencing overall survival after Lu-177-PSMA-617 radioligand therapy in metastatic prostate cancer

• Published in: Nuklearmedizin. Nuclear medicine Vol. 61; no. 1; p. 25
• Main Authors: Schneider, Charlotte A, Täger, Philipp, Hammes, Jochen, Fischer, Thomas, Drzezga, Alexander, Pfister, David, Heidenreich, Axel, Schmidt, Matthias
• Format: Journal Article
• Language: English
• Published: Germany 01-02-2022
• Subjects: Aged; Aged, 80 and over; Dipeptides - therapeutic use; Heterocyclic Compounds, 1-Ring - therapeutic use; Humans; Lutetium; Male; Middle Aged; Prostate-Specific Antigen; Prostatic Neoplasms, Castration-Resistant - radiotherapy; Radioisotopes - therapeutic use; Retrospective Studies; Treatment Outcome
• ISSN: 2567-6407
• DOI: 10.1055/a-1670-9500

To examine the clinical benefit of Lu-177-PSMA-617 radioligand therapy for patients with metastatic castration-resistant prostate cancer (mCRPC).
Between November 2014 and December 2018, a total of 56 consecutive patients (median age 69.5 years; range 55-84 years) with mCRPC were included in this retrospective analysis. Patients received between 1 and 4 therapy cycles with a mean activity of 6.8 GBq per cycle. Biochemical response was evaluated using Prostate Cancer Working Group Criteria 3 (PCWG 3). Survival was assessed using Kaplan-Meier estimates and Cox proportional hazards regression analysis. This retrospective study was approved by the local ethics committee.
A total of 139 treatment cycles with Lu-177-PSMA-617 were performed. A decline of 50% or more of prostate-specific antigen (PSA) level occurred in 54% and a PSA decline of any amount in 65% of patients. The estimated median overall survival (OS) was 16 months, in the chemotherapy subgroup 14 months. A longer OS was associated with a PSA-decline ≥50%, more than 2 cycles of therapy, cumulative activity >15 GBq and an initial alkaline phosphatase ≤ 220 [U/l]. These identified predictors remained significant on uni- and multivariate Cox regression analysis. Moreover, 40% of the patients who were non-responders after the first therapy cycle turned into responders after the second one.
PSA-decline ≥50%, a cumulative activity >15 GBq and an initial alkaline phosphatase ≤ 220 [U/l] were identified as key predictors of prolonged OS in patients with mCRPC. In contrast rapid clinical deterioration mostly due to skeletal carcinomatosis resulted in early treatment failure.