PSMA expression is influenced by hormonal status. We evaluated changes in PSA and whole-body 68Ga-PSMA-11 PET/CT (WB-PSMA PET) after initiation of androgen receptor signaling inhibitors (ARSi).
Prospectively enrolled patients with metastatic castration-resistant prostate cancer (mCRPC) initiating ARSi underwent serial PSA measurements and WB-PSMA PET at baseline, 1-week, and 3-months post-ARSi. We correlated WB-PSMA PET metrics and PSA kinetics after ARSi to 1-year clinical outcome.
Due to low enrollment rate, the study was closed before reaching the recruitment goal of 30 patients. Nine patients were enrolled. At 1-year, unfavorable outcome was documented in 6/9 (66%) patients. Nine/9 patients completed PSMA PET at 1-week, 5/9 at 3-months. Changes in PSA, PSMA-VOL, SUVmean and SUVmax were - 12%, + 5%, + 3%, and + 10% at 1-week, - 42%, - 16%, - 15% and - 17% at 3-months, respectively.
Our prospective trial involving 9 mCRPC patients initiating ARSi did not show significant modulation of PSMA expression measured on WB-PSMA PET at 1-week. This study was registered on clinicaltrials.gov (NCT04279561).
EJNMMI research. 2023 Oct 30*** epublish ***
Ida Sonni, Andrei Gafita, Lena M Unterrainer, Rejah M Alano, Stephanie Lira, John Shen, Alexandra Drakaki, Tristan Grogan, Matthew B Rettig, Johannes Czernin, Jeremie Calais
Department of Molecular and Medical Pharmacology, University of California, Los Angeles, Los Angeles, CA, USA. ., Department of Molecular and Medical Pharmacology, University of California, Los Angeles, Los Angeles, CA, USA., Department of Medical Oncology, University of California, Los Angeles, Los Angeles, CA, USA., Department of Medicine Statistics Core, University of California, Los Angeles, Los Angeles, CA, USA.