Posted March 20, 2013
Dr. Scott Tagawa, Weill Cornell Medical College
Many men with prostate cancer suffer from biochemical relapse (rising PSA) after surgery and/or radiation. Hormonal therapy can control this state of disease temporarily, but most men will continue to have PSA levels that continue to rise. This state represents micro-metastatic disease, meaning tiny tumors that are in the body but too small to see by traditional imaging (CT, MRI, or bone scans). To address this, and to also address the need for better treatments for advanced prostate cancer, Dr. Scott Tagawa, using support from his FY08 PCRP Clinical Trial Award, has collaborated with a research team led by Dr. Neil Bander at Weill Cornell Medical College to develop an antibody, called J591, which specifically recognizes prostate specific membrane antigen (PSMA), allowing prostate cancer cells to be targeted in a very specific manner.
PMSA is a cell-surface protein expressed by the vast majority of prostate cancer cells and generally not present elsewhere in the human body. By attaching J591 to a tiny radioactive particle (177Lu), a small amount of radiation is delivered to the cancer cells and can be used for treatment of tumors or for imaging to visualize tumors. The research team has been utilizing J591 in patients with metastatic prostate cancer for over a decade, with success in targeting metastatic tumors and benefitting patients with decreases in PSA, tumor size, and pain symptoms. Their Clinical Trial Award has allowed them to expand on the clinical testing of J591 through a multi-site, phase 2 clinical trial combining hormonal therapy with targeted J591 radiation, bringing the radiation particle to unseen tumors. They are also testing to see if a specialized type of a scan using the radiolabeled antibody can visualize these small sites of cancer that can't be seen on standard scans.
To date, the trial has opened at various sites across the country and has shown that some of the men with non-metastatic prostate cancer treated with 177Lu-J591 have benefitted in terms of PSA reduction, with good tolerance to the treatment. It is hoped that the treatment will either prevent or delay the onset of metastatic disease. The investigators have leveraged the funds from the PCRP clinical trial award amass a large group of collaborative researchers (see photo) to move this exciting new treatment forward. Plans are underway to initiate a phase 3 study to move radiolabeled J591 closer to possible FDA approval.