Prostate cancer is the most common cancer to affect men in the United States and the second most common cancer in men worldwide. Prostate-specific membrane antigen (PSMA)-based positron emission tomography (PET) imaging is gradually recognized as a novel technique that can improve treatment decisions and affect clinical care of prostate cancer patients as the PSMA expression in most prostate malignant cells correlates well with serum prostate-specific antigen concentration. Initial development of PSMA-targeted radiopharmaceuticals is based on monoclonal antibodies such as ProstaScint™; however, because small molecules are advantageous due to faster blood clearance and better tumor permeability, the focus of current investigative efforts is therefore switched to developing PSMA inhibitor-based radiopharmaceuticals, as they are typically small molecular agents. To date, several 68Ga and 18F-labeled PSMA-targeted molecules have shown promising results in patients with biochemical recurrent prostate cancer using PET/computed tomography (CT). Studies of these PSMA-targeted radiopharmaceuticals also suggest a higher sensitivity and specificity, along with an improved detection rate over conventional imaging (CT scan and methylene diphosphonate bone scan) or 11C/18F-choline PET/CT. In addition, the tracers based on PSMA-617 and PSMA I&T can be labeled with α and β- emitters (e.g., 225Ac, 90Y, and 177Lu) as well and serve as a theranostic tool for patients with metastatic prostate cancer. While the clinical impact of such concept remains to be verified, the preliminary results of PSMA molecular radiotherapy are very encouraging. With these in mind, the aim of this article is to provide an overview of the recent advancement of PSMA-targeted radiopharmaceuticals and their clinical applications.
Cancer biotherapy & radiopharmaceuticals. 2020 Jun 23 [Epub ahead of print]
Mai Lin, Robert T Ta, Kalevi Kairemo, Dao B Le, Gregory C Ravizzini
Cyclotron Radiochemistry Facility, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA., Department of Nuclear Medicine and Molecular Radiotherapy, Docrates Cancer Center, Helsinki, Finland., Department of Nuclear Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA.