Researchers from National Cancer Institute has tested the efficacy of a new combination therapy of combining cancer vaccines and Anti-androgen hormone therapy to Prostate cancer patients who showed resistance to hormone therapy but had no metastatic disease. The Phase II trial was conducted in 42 Prostate cancer patients with no metastatic spread but having high Prostate Specific Antigen (PSA) values. The results of the study were published in the Journal of Urology.
Prostate cancer can spread to other regions after initial local treatment and requires continuous follow up with hormone therapy. The resistance to hormone therapy is also the cause of cancer recurrence in the same region or other sites. The incidence of occurrence can be detected by observing rise in PSA values. This study was done to find out the efficacy of Cancer vaccines combination with anti-androgen therapy for prostate cancer. . Cancer vaccines are designed either to treat existing cancers or to prevent the development of cancer. The experimental vaccine used in this study was designed to strengthen the body's natural defenses against prostate cancer.
"The question is what you do for someone who has already failed standard therapy with hormones?" said Philip M. Arlen, M.D., of NCI's Laboratory of Tumor Immunology and Biology. "This study was designed to answer that question and examined a population of patients whose cancers were resistant to hormone therapy, had no metastatic disease that was observable by computed tomography (CT or CAT) scan, but had a rising PSA score, an indicator of recurrence."
The anti-androgen hormone Nilutamide works by blocking the effects of excess testosterone, a hormone produced by the body that can promote the growth of cancer cells. No serious side effects are produced from the drug Nilutamide other than lung toxicities. Hormone therapy increases the number of immune cells reaching the prostate gland and helps in immune surveillance which increases the effectiveness of cancer vaccines.
The positive effects of combining anti-androgen therapy to vaccine "may be because the vaccine acts to 'prime' the immune system, and when you add the hormone treatment, it allowed the vaccine to work even better," explained Arlen. "Our study indicates there may well be a synergy between immunotherapy with vaccines and hormone deprivation."
"Our goal moving forward is to introduce the vaccines into earlier treatment stages," Arlen said. "We have shown that this therapy is safe and well-tolerated. Next we want to keep this population of patients either stable or improving, and also prevent metastatic disease. Achieving that would be a tremendous benefit in terms of their quality of life."
Source: National Cancer Institute.