title: Clinical trials of cancer therapies targeting prostate-specific membrane antigen.
abstract: Prostate cancer is the most common non-cutaneous cancer of men in the United States and represents their second-leading cause of cancer-related death. Metastatic disease is largely resistant to conventional chemotherapies, and targeted therapies are urgently needed. Prostate-specific membrane antigen (PSMA) is a prototypical cell-surface marker of prostate cancer. PSMA is an integral, non-shed, type 2 membrane protein with abundant and nearly universal expression in prostate carcinoma, but has limited extra-prostatic expression. In addition, PSMA is expressed in the neovasculature of other solid tumors. These findings have spurred development of PSMA-targeted therapies for cancer, and first-generation products have entered clinical testing. Vaccine approaches have included recombinant protein, nucleic acid and cell-based strategies, and anti-PSMA immune responses have been demonstrated in the absence of significant toxicity. Therapy with drug-conjugated and radiolabeled antibodies has yielded objective clinical responses as measured by reductions in serum prostate-specific antigen and/or imageable tumor volume. However, responses were observed in a minor fraction of patients and at doses near the maximum tolerated dose. Overall, these initial studies have provided measured proof of concept for PSMA-based therapies, and second-generation antibody and vaccine products may hold the key to exploit PSMA for molecularly targeted therapy of prostate and other cancers.
authors.affiliation: PSMA Development Company, LLC, Tarrytown, NY, USA.
authors.forename: William C
authors.initials: WC
authors.lastname: Olson
authors.forename: Warren D W
authors.initials: WD
authors.lastname: Heston
authors.forename: Ayyappan K
authors.initials: AK
authors.lastname: Rajasekaran
mesh_terms: D000911:Antibodies, Monoclonal / Q000627:therapeutic use; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D019496:Cancer Vaccines / Q000627:therapeutic use; D002986:Clinical Trials as Topic; D006801:Humans; D018796:Immunoconjugates / Q000627:therapeutic use; D008297:Male; D017430:Prostate-Specific Antigen / Q000037:antagonists & inhibitors*; D011471:Prostatic Neoplasms / Q000188:drug therapy*; D016499:Radioimmunotherapy
chemical_list: D000911:Antibodies, Monoclonal; D000970:Antineoplastic Agents; D019496:Cancer Vaccines; D018796:Immunoconjugates; D017430:Prostate-Specific Antigen