Development of a Single Vial Kit Solution for Radiolabeling of 68Ga-DKFZ-PSMA-11 and Its Performance in Prostate Cancer Patients
University of Pretoria and Steve Biko Academic Hospital, Crn Malherbe and Steve Biko Rd, Pretoria, South Africa; School of Health Sciences, Catalysis and Peptide Research Unit, E-Block 6th Floor, Westville Campus, University Road, Westville, Durban, South Africa; South African Nuclear Energy Corporation (Necsa), Building P1600, Radiochemistry, Pelindaba, Brits, South Africa; Department of Science and Technology, Preclinical Drug Development Platform, North West University, 11 Hoffman St, Potchefstroom, South Africa
Prostate-specific membrane antigen (PSMA), a type II glycoprotein, is highly expressed in almost all prostate cancers. By playing such a universal role in the disease, PSMA provides a target for diagnostic imaging of prostate cancer using positron emission tomography/computed tomography (PET/CT). The PSMA-targeting ligand Glu-NH-CONH- Lys-(Ahx)-HBED-CC (DKFZ-PSMA-11) has superior imaging properties and allows for highly-specific complexation of the generator-based radioisotope Gallium-68 (68Ga). However, only module-based radiolabeling procedures are currently available. This study intended to develop a single vial kit solution to radiolabel buffered DKFZ-PSMA-11 with 68Ga. A 68Ge/68Ga-generator was utilized to yield 68GaCl3 and major aspects of the kit development were assessed, such as radiolabeling performance, quality assurance, and stability. The final product was injected into patients with prostate cancer for PET/CT imaging and the kit performance was evaluated on the basis of the expected biodistribution, lesion detection, and dose optimization. Kits containing 5 nmol DKFZ-PSMA-11 showed rapid, quantitative 68Ga-complexation and all quality measurements met the release criteria for human application. The increased precursor content did not compromise the ability of 68Ga-DKFZ-PSMA-11 PET/CT to detect primary prostate cancer and its advanced lymphaticand metastatic lesions. The 68Ga-DKFZ-PSMA-11 kit is a robust, ready-to-use diagnostic agent in prostate cancer with high diagnostic performance. © 2015 by the authors.