A UW Carbone Cancer Center (UWCCC) researcher is working to develop a vaccine that would stimulate the immune system to kill prostate cancer cells, even before the cancer can be spotted on scans.
Dr. Douglas McNeel, associate professor of medicine at the University of Wisconsin School of Medicine and Public Health (SMPH), is testing a vaccine that targets a protein made by prostate cancer cells. McNeel said the vaccine could potentially benefit men whose PSA (prostate-specific antigen) levels are rising after surgery or radiation therapy but whose prostate cancer cells cannot yet be detected by scans.
“The concept behind tumor vaccines is to train the immune system to recognize the tumor as something it should reject,” said McNeel. The vaccine therapy would be in contrast to chemotherapy which uses chemicals to kill cancer cells. McNeel says so far, side effects of this vaccine, and most vaccines that have been studied by other groups, are minor, including fever and chills. Chemotherapy can cause more significant side effects including nausea, vomiting, hair loss, and risk of infections.
Clinical trials have shown immune responses to the vaccine and the slowing of the rate at which PSA levels rise. McNeel says he is studying the vaccine in different schedules on patients who have more advanced disease, are not responding to hormonal therapy, and whose PSA levels continue to rise. He’s also researching the vaccine to see if it delays the development of metastases. McNeel’s work has included studying different target proteins for new vaccines.
Another prostate-cancer vaccine (sipuleucel-T, Provenge®) was approved by the Food and Drug Administration (FDA) in 2010 for use in patients with advanced disease. The UWCCC, where the vaccine is now available, was one of several institutions that participated in a clinical trial leading to its approval. Provenge® works differently than the vaccine that McNeel is developing. The immunotherapy is made from the patient’s own cells and infused back into the patient two to three days after the cells are extracted and processed.
“Clinical trials on the vaccine indicated that the median survival for those treated with Provenge® was about four months longer than the patients who received a placebo,” said McNeel.
In 2010, nearly 218,000 of new prostate cancer cases were reported in the U.S. The National Cancer Institute says 32,000 men died from prostate cancer last year.