Journal Article

Phase 2 trial of PSMA PET CT versus planar bone scan and CT in prostate cancer patients progressing while on androgen deprivation therapy

Shen, John, Benz, Matthias R., Rettig, Matthew, Alano, Rejah, Djaïleb, Loïc, Gafita, Andrei, Hotta, Masatoshi, Grogan, Tristan, Sonni, Ida, Nikitas, John, Armstrong, Wesley, Calais, Jeremie, Farolfi, Andrea, Czernin, Johannes, Liu, Sandy

2024

Overview

For prostate cancer patients who experience biochemical progression during androgen deprivation therapy (ADT), prostate-specific membrane antigen positron emission tomography/computed tomography (PSMA PET/CT) has not been prospectively compared to planar bone scan plus CT. This was a single-arm, head-to-head, prospective phase II trial (NCT04928820) designed to enroll 102 men with prostate cancer who experienced biochemical progression (rising prostate-specific antigen [PSA] ≥ 1 ng/mL) during ADT. All patients received 68Ga-PSMA-11 PET/CT and 99mTc-MDP planar bone scans. Each scan was interpreted by three central independent readers. The primary endpoint was the per-patient bone metastasis detection rate of PSMA PET/CT versus planar bone scan and CT. Secondary endpoints compared the number of bone metastases detected per patient and the inter-reader agreement of each imaging modality. Twenty-two men were enrolled between July 2021 and June 2022. Due to slow accrual following approval of PSMA PET radiotracers in the U.S. and a lack of a statistical signal between the two imaging modalities on interim analysis, this trial was closed early on October 2022. Median PSA was 8.5 ng/mL (interquartile range: 1.6–77.6). There was 100% agreement between the two scans. Six patients (27%) had negative findings and 16 patients (73%) had positive findings on both scans. PSMA PET/CT and bone scan plus CT detected an equal number of bone lesions for 14 patients (64%), PSMA PET/CT detected more bone lesions for six patients (27%), and bone scan plus CT detected more bone lesions for two patients (9.1%) (p = 0.092). The inter-reader agreement rates of PSMA PET/CT and bone scan plus CT were 96% and 82%, respectively ( p  = 0.25). In men with biochemical progression during ADT, 68Ga-PSMA-11 PET/CT and 99mTc-MDP planar bone scan plus CT had identical bone metastasis detection rates. Bone scan plus CT can continue to serve as a cost-effective and readily accessible restaging modality in patients with biochemical progression. ClinicalTrials.gov NCT04928820. Registered 16/06/2021.

• Publisher: Nature Publishing Group UK,Nature Publishing Group,Nature Portfolio
• Subject: 631/67/1344 / 631/67/589/466 / 692/308/2779/109 / 692/4028/67/2321 / 692/700/1421/1771 / 692/700/1421/2109 / 692/700/1421/2770 / Aged / Aged, 80 and over / Androgen Antagonists - therapeutic use / Androgen deprivation therapy / Androgens / Antigens / Antigens, Surface - metabolism / Biochemical recurrence / Bone and Bones - diagnostic imaging / Bone and Bones - drug effects / Bone and Bones - metabolism / Bone and Bones - pathology / Bone cancer / Bone imaging / Bone lesions / Bone metastases / Bone Neoplasms - diagnostic imaging / Bone Neoplasms - drug therapy / Bone Neoplasms - secondary / Bone scan / Computed tomography / Disease Progression / Gallium Isotopes / Gallium Radioisotopes / Glutamate Carboxypeptidase II - metabolism / Humanities and Social Sciences / Humans / Lesions / Male / Metastases / Metastasis / Middle Aged / multidisciplinary / Patients / Positron emission tomography / Positron Emission Tomography Computed Tomography - methods / Prospective Studies / Prostate cancer / Prostate-specific antigen / Prostate-Specific Antigen - blood / Prostate-specific membrane antigen PET/CT / Prostatic Neoplasms - diagnostic imaging / Prostatic Neoplasms - drug therapy / Prostatic Neoplasms - pathology / Radioactive tracers / Radiopharmaceuticals / Science / Science (multidisciplinary) / Scintigraphy / Tomography / Tomography, X-Ray Computed - methods