"This is good news for our prostate cancer patients," says Mario Eisenberger, M.D., co-chair of the study and the R. Dale Hughes Professor of Oncology at the Johns Hopkins Kimmel Cancer Center. "These data indicate that the current standard of care for these patients should be docetaxel therapy, and we should try adding new agents to build upon this success and test it in patients with aggressive disease before the cancer spreads."
Eisenberger co-chaired the global study that enrolled patients in 24 countries. With colleagues from Erasmus University in the Netherlands and Princess Margaret Hospital in Toronto, the research team randomly assigned 1,006 hormone-resistant prostate cancer patients to receive intravenous docetaxel (every three weeks or weekly) or the current standard chemotherapy drug, called mitoxantrone, which is approved mainly for reducing pain associated with tumor spread. Patients receiving docetaxel every three weeks survived 2.4 months longer on average than those receiving mitoxantrone or docetaxel weekly.
"The study's statistics are very robust. Two months may not sound like much time to most people, but the study shows that prostate cancer responds to docetaxel and this opens up the door to explore more options," says Eisenberger. The study results also show significant improvements in pain relief and lowering prostate specific antigen blood levels.
Side effects like low blood counts, fever, hair loss and nausea were seen more often in 25 percent of patients on the tri-weekly regimen of docetaxel, but many of the side effects are manageable, according to the study authors. All study participants received prednisone to improve symptoms.
Docetaxel, tradenamed Taxotere, is based on an extract from the needles of the English yew plant, and currently is used to treat metastatic breast cancer. It kills cancer cells by disrupting formation of the internal skeleton that allows cells to divide and multiply.
Other therapies that may boost docetaxel effectiveness include radiopharmaceuticals targeted at cancer cells that have spread to the bone or drugs that block prostate cancer growth genes. Based on the results of this study, docetaxel was approved on May 19, 2004 as first-line therapy for hormone refractory prostate cancer by the Food and Drug Administration.
Prostate cancer affects more than 230,000 men in the United States annually, and as the second leading cause of cancer deaths, almost 30,000 will die from the disease each year. Eighty percent of prostate cancer patients with advanced disease respond to initial hormone therapy to decrease testosterone levels, but most relapse within an average of two years.
This study was funded by Aventis Pharmaceuticals Inc.
Abstract # 4, Proceedings of the American Society of Clinical Oncology, 2004.
Links:
Johns Hopkins Kimmel Cancer Center: http://www.hopkinskimmelcancercenter.org/
Brady Urological Institute at Johns Hopkins: http://urology.jhu.edu/
Patients Living with Cancer Guide to Prostate Cancer: http://www.plwc.org/