According to the results of a study recently presented at the 2005 American Society of Clinical Oncology, the vaccine Provenge® improves survival in asymptomatic hormone resistant prostate cancer.
The prostate is a gland of the male reproductive system that is responsible for producing some of the fluid that transports the sperm during male ejaculation. Prostate cancer is a disease in which cancer cells form in the tissues of the prostate. Prostate cancer is the most common form of cancer diagnosed in men, after skin cancer. The outlook for men diagnosed with prostate cancer is good and 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 lower the presence or block the effects of testosterone that can stimulate the growth the growth of hormone dependent types of prostate cancer. Some types of prostate cancer can become resistant to hormonal therapy and will then necessitate a different treatment approach; this condition is known as hormone refractory prostate cancer.
Provenge is a vaccine made from the proteins found in prostate cancers. Provenge is manufactured to present the patient’s immune system with a target it against which it can mount a response. Hormone refractory prostate cancer can be difficult to treat, so novel approaches such as immune stimulating vaccines are providing hopes of a better outcome for these patients.
Researchers conducted this phase III trial among men with asymptomatic, metastatic hormone refractory prostate cancer. Each patient was randomized to receive either Provenge or placebo over a four-week period. Results of the study indicated that the average survival was 25.9 months for those treated with Provenge, compared to 21.4 months for those who received placebo, representing a 4.5-month improvement. After three years, 34% of patients treated with Provenge were still alive, compared to 11% of patients who received placebo. Fever and shaking chills were the most commonly reported effects associated with Provenge.
The researchers concluded that Provenge appears to improve survival in patients with hormone refractory prostate cancer compared to placebo and is generally well tolerated. Larger phase III clinical trials are underway to evaluate Provenge and provide further data to the U.S. Food and Drug Administration (FDA).
Reference: Small E, Schellhammer P, Higano C, et al. Results of a Placebo-Controlled Phase III Trial of Immunotherapy with APC8015 for Patients with Hormone Refractory Prostate Cancer(HRPC). Proceedings from the 2005 annual meeting of the American Society of Clinical Oncology (ASCO). Abstract #4500.