68 Ga-RM2 PET-MRI versus MRI alone for evaluation of patients with biochemical recurrence of prostate cancer: a single-centre, single-arm, phase 2/3 imaging trial

• Published in: The lancet oncology 2024-04, Vol.25 (4), p.501
• Main Authors: Duan, Heying, Moradi, Farshad, Davidzon, Guido A, Liang, Tie, Song, Hong, Loening, Andreas M, Vasanawala, Shreyas, Srinivas, Sandy, Brooks, James D, Hancock, Steven, Iagaru, Andrei
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Antigens; Bone imaging; Gallium Radioisotopes; Gastrin; Histopathology; Humans; Lesions; Localization; Lymphatic system; Magnetic Resonance Imaging; Male; Metastasis; Patients; Peptides; Pharmaceuticals; Physiology; Positron Emission Tomography Computed Tomography - methods; Positron-Emission Tomography - methods; Prostate cancer; Prostate-Specific Antigen; Prostatectomy; Prostatic Neoplasms - diagnostic imaging; Prostatic Neoplasms - therapy; Radiation therapy; Radioisotopes; Scintigraphy
• ISSN: 1470-2045; 1474-5488
• DOI: 10.1016/S1470-2045(24)00069-X

National Comprehensive Cancer Network guidelines include prostate-specific membrane antigen (PSMA)-targeted PET for detection of biochemical recurrence of prostate cancer. However, targeting a single tumour characteristic might not be sufficient to reflect the full extent of disease. Gastrin releasing peptide receptors (GRPR) have been shown to be overexpressed in prostate cancer. In this study, we aimed to evaluate the diagnostic performance of the GRPR-targeting radiopharmaceutical Ga-RM2 in patients with biochemical recurrence of prostate cancer. This single-centre, single-arm, phase 2/3 trial was done at Stanford University (USA). Adult patients (aged ≥18 years) with biochemical recurrence of prostate cancer, a Karnofsky performance status of 50 or higher, increasing prostate-specific antigen concentration 0·2 ng/mL or more after prostatectomy or 2 ng/mL or more above nadir after radiotherapy, and non-contributory conventional imaging (negative CT or MRI, and bone scan) were eligible. All participants underwent Ga-RM2 PET-MRI. The primary outcome was the proportion of patients with PET-positive findings on Ga-RM2 PET-MRI compared with MRI alone after initial therapy, at a per-patient and per-lesion level. The primary outcome would be considered met if at least 30% of patients had one or more lesions detected by Ga-RM2 PET-MRI and the detection by Ga-RM2 PET-MRI was significantly greater than for MRI. Each PET scan was interpreted by three independent masked readers using a standardised evaluation criteria. This study is registered with ClinicalTrials.gov, NCT02624518, and is complete. Between Dec 12, 2015, and July 27, 2021, 209 men were screened for eligibility, of whom 100 were included in analyses. Median follow-up was 49·3 months (IQR 36·7-59·2). The primary endpoint was met; Ga-RM2 PET-MRI was positive in 69 (69%) patients and MRI alone was positive in 40 (40%) patients (p