(UroToday.com) The 2024 GU ASCO annual meeting featured a prostate cancer session and a presentation by Dr. Boris Hadaschik discussing baseline characteristics of patients with PSMA-PET–positive and –negative disease with high-risk of biochemical recurrence after radical prostatectomy in the ongoing phase 3 PRIMORDIUM study.
PSMA-PET is more sensitive and specific than conventional imaging for the detection of lesions in patients with biochemical recurrence prostate cancer. The PRIMORDIUM study includes standardized PSMA-PET imaging and enrolls PSMA-PET positive patients (≥1 locoregional lesion, interventional cohort) and PSMA-PET negative patients (no lesion, observational cohort). The following highlights PRIMORDIUM location in the prostate cancer pathway:
All patients are non-metastatic by conventional imaging at screening.
All patients enrolled in PRIMORDIUM have high-risk biochemical recurrence (PSA doubling time ≤12 months or Gleason score ≥8) after radical prostatectomy. PSMA-PET-positive patients are randomized 1:1 to either the control arm (whole pelvic salvage radiotherapy + 6 months of LHRH agonist) or the interventional arm (radiotherapy + LHRH agonist + apalutamide 240 mg/day for 180 days):
Stereotactic body radiotherapy to ≤3 distant lesions is optional, and PSMA-PET-negative patients are managed per routine clinical practice. The following tables show the baseline characteristics of those in the interventional cohort (n = 88) and in the observational cohort (n = 110):
In the interventional cohort, the median age is 69 (IQR 65-74) years, with a median PSA prior to PSMA PET of 0.51 ng/mL (95% CI 0.30-1.30). Regarding PSMA PET findings, all patients have locoregional lesions and 10.2% have distant metastasis. In the observational cohort, the median age is 66.5 (IQR 61-72) years, with a median PSA prior to PSMA PET of 0.35 ng/mL (95% CI 0.24-0.60). There were 58.2% of patients that had an extended lymph node dissection. As of January 12, 2023, 16 countries have enrolled patients onto PRIMORDIUM:
As of December 31, 2023, the following countries are active, stratified by before and after the data cutoff:
Dr. Hadaschik concluded his presentation discussing baseline characteristics of patients with PSMA-PET–positive and –negative disease with high-risk of biochemical recurrence after radical prostatectomy in the ongoing phase 3 PRIMORDIUM study with the following take-home points:
- The PRIMORDIUM study aims to evaluate the intensification of treatment with apalutamide for patients assessed with PSMA-PET
- From 198 enrolled patients with high-risk biochemical recurrence, positive PSMA-PET was documented in 44% of patients at a median of 39 months after radical prostatectomy and a median PSA of 0.51 ng/mL, while negative PSMA-PET was observed in 56% of patients at a median of 26 months after radical prostatectomy and a median PSA of 0.35 ng/mL
- In this analysis, all PSMA-PET-positive patients had locoregional lesion(s) and 10% also had distant lesion(s) on PSMA-PET imaging
Presented by: Boris A. Hadaschik, Department of Urology, University of Duisburg-Essen and German Cancer Consortium (DKTK) -University Hospital Essen, Essen, Germany
Written by: Zachary Klaassen, MD, MSc – Urologic Oncologist, Associate Professor of Urology, Georgia Cancer Center, Wellstar MCG Health, @zklaassen_md on Twitter during the Genitourinary (GU) American Society of Clinical Oncology (ASCO) Annual Meeting, San Francisco, CA, Thurs, Jan 25 – Sat, Jan 27, 2024.
Related content: PRIMORDIUM Trial Evaluates Apalutamide Plus ADT for High Risk Biochemical Recurrence of Prostate Cancer After Prostatectomy - Boris Hadaschik