The immunotherapeutic vaccine GVAX® provides promising activity in patients with recurrent prostate cancer. These results were recently presented at the 2008 annual meeting of the American Association for Cancer Research.
The prostate is a gland of the male reproductive system. It produces some of the fluid that transports sperm during ejaculation. After skin cancer prostate cancer is the most common form of cancer diagnosed in men. The outlook for men diagnosed with prostate cancer is good: overall survival rates for all stages of prostate cancer have improved dramatically over the past 20 years.
Current treatment options for prostate cancer include watchful waiting, surgery, chemotherapy, radiation, or hormonal therapy. Hormonal therapy is designed to block testosterone from stimulating the growth of hormone-dependent types of prostate cancer. Hormone therapy and chemotherapy are often associated with significant side effects, which may lead to a decline in quality of life for patients.
Some prostate cancers return following therapy, a condition referred to as recurrent prostate cancer. Because recurrent prostate cancer can be difficult to treat, new approaches-such as immunotherapy agents-are being explored. The goal of these agents is to produce an immune response that helps the body fight cancer cells.
GVAX is an immunotherapy agent that stimulates the patient’s immune system to target and kill cancerous prostate cells. It is currently in the last phases of clinical trials prior to FDA review for the treatment of prostate cancer that has stopped responding to hormone therapy, referred to as hormone refractory prostate cancer.
Researchers from several medical institutions recently conducted an early-phase clinical trial to evaluate GVAX as a single agent for the treatment of recurrent prostate cancer. This trial included 19 patients who had been previously treated with a prostatectomy (surgery to remove the prostate and cancerous surrounding tissues) and/or radiation therapy. Patients did not have cancer spread to distant sites in the body. Patients had experienced a recurrence of their cancer and had not yet received treatment with hormone therapy. Patients were treated with GVAX for up to six months.
- At a median follow-up of six years, 17 of the 19 patients remain alive.
- The amount of time it took for prostate-specific antigen (PSA) levels to double was increased to 57.1 weeks following GVAX compared with 28.7 weeks prior to treatment with GVAX. (PSA levels are a measure of the progression of prostate cancer; higher levels indicating a more-advanced stage of prostate cancer.)
- The most common side effects of GVAX were reactions at the injection site and flu-like symptoms.
The researchers concluded that GVAX appears to provide promising anticancer activity among men with recurrent prostate cancer that has not spread to distant sites. In addition, GVAX may provide a more tolerable treatment option than hormone therapy for this group of patients, however further study is necessary to address this issue.
Patients with recurrent prostate cancer may wish to speak with their physician regarding their individual risks and benefits of all treatment options, including the participation in a clinical trial evaluating novel therapeutic approaches. Two sources of information regarding ongoing clinical trials include the National Cancer Institute (www.cancer.gov) and www.eCancerTrials.com.
Reference: Cell Genesys. Cell Genesys announces encouraging results from phase 1/2 trial of GVAX immunotherapy for prostate cancer in recurrent disease. Available at: https://phx.corporate-ir.net/phoenix.zhtml?c=98399&p=irol-newsArticle&ID=1128398&highlight=. Accessed April 2008.
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