According to results recently published in Clinical Cancer Research, the immunotherapeutic agent GVAX® provides anticancer activity and is generally well tolerated among men with hormone-refractory prostate cancer who have not received prior chemotherapy. Higher doses of GVAX appear to provide improved outcomes compared with lower doses in this patient population.
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 become resistant to hormonal therapy and then require a different treatment approach; this condition is known as hormone refractory prostate cancer (HRPC). Since hormone refractory 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 HRPC. Ipilimumab is also an agent that helps enable the immune system; it is also in the last phase of clinical trials prior to FDA review. GVAX has demonstrated anticancer activity both as a single agent and in combination with other agents, such as ipilimumab, for the treatment of HRPC; updated results from trials studying these approaches continue to be reported.
Researchers from several medical centers in the United States recently conducted a clinical trial to further evaluate the effectiveness of GVAX in the treatment of HRPC. This trial included 55 men who had not been treated with chemotherapy. Thirty four men had disease progression that could be assessed on scans, and 21 men had a rising prostate specific antigen (PSA) level. One group of patients was treated with a higher dose of GVAX, while the other group received a lower dose of GVAX.
- Median survival was nearly three years for patients treated with a higher dose of GVAX compared with two years for those treated with the lower dose of GVAX.
- Median time to cancer progression was five months for patients treated with a higher dose of GVAX compared with three months for those treated with the lower dose.
The researchers concluded that these results provide further evidence that GVAX provides anticancer activity among men with HRPC whose disease is progressing, particularly with the higher doses of GVAX used in this trial. Patients with HRPC may wish to speak with their physician regarding their individual risks and benefits of participating in a clinical trial further evaluating GVAX or other promising therapeutic agents. Two sources of information regarding ongoing clinical trials include the National Cancer Institute (www.cancer.gov) and www.eCancerTrials.com.
Reference: Small E, Sacks N, Nemunaitis J, et al. Granulocyte macrophage colony-stimulating factor-secreting allogeneic cellular immunotherapy for hormone-refractory prostate cancer. Clinical Cancer Research. 2007; 13: 3883-3891.
Related News: GVAX® plus Ipilimumab Promising for Hormone-refractory Prostate Cancer (8/3/2007)
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