ESMO 2021: PSMAddition: A Phase III Trial to Compare Treatment with 177Lu-PSMA-617 plus Standard of Care (SOC) Versus SOC Alone in Patients with Metastatic Hormone-Sensitive Prostate Cancer

( Lutetium-177 is a radioligand that when bound to a prostate-specific membrane antigen (PSMA) targeting molecule delivers beta-particle radiation to PSMA-expressing cells and their local microenvironment. This therapy depends on prostate cancer cell surface expression of PSMA, which may be altered by androgen pathway inhibitors. To optimize the utility of this treatment modality in metastatic hormone-sensitive prostate cancer (mHSPC), the PSMAddition trial (NCT04720157) was designed.

This study is an international prospective open-label, randomized, phase III trial in adults with mHSPC. Patients who are treatment-naïve or minimally pre-treated with good ECOG performance status will receive a Gallium-68 PSMA-11 PET scan. Patients with PSMA-positive disease will be randomized 1:1 to receive 177Lu-PSMA-617 (7.4 GBq i.v. every 6 weeks, ≤ 6 cycles) plus standard of care or standard of care alone (control arm). In this case, standard of care will be an androgen pathway inhibitor plus testosterone suppression. Patients will be stratified by tumor volume, age, and prior treatment for prostate cancer. The primary endpoint is radiographic progression-free survival. Crossover is allowed for patients in the control arm who are progressing on standard of care. A total of 1126 patients are planned for accrual.

Presented by: Scott T. Tagawa MD, Department of Urology, Weill Cornell Medical Center, New York, NY

Written by: Alok Tewari, MD, PhD – Genitourinary Medical Oncologist, Instructor in Medicine, Dana-Farber Cancer Institute, Harvard Medical School, Twitter: @aloktewar during the 2021 European Society for Medical Oncology (ESMO) Annual Congress 2021, Thursday, Sep 16, 2021 – Tuesday, Sep 21, 2021.