The ASCENT (AIPC Study of Calcitriol Enhancing Taxotere) study is a multicenter, randomized, double-blind trial based on the promising results of a preliminary study in Oregon. ASCENT will determine whether a high dose of an active form of vitamin D, called calcitriol, taken once a week in combination with docetaxel, is any more effective than docetaxel alone for patients with androgen-independent prostate cancer (AIPC), an advanced form of prostate cancer.
"Late-stage prostate cancer patients have few treatment options, and we are cautiously hopeful that this study will further confirm and extend the promising results we've already seen with docetaxel in combination with high-dose pulse administration (HDPA) calcitriol," said OHSU Cancer Institute oncologist Tomasz Beer, M.D., study chairman and assistant professor of medicine (hematology and medical oncology) in the OHSU School of Medicine.
The study will enroll approximately 232 patients at about 20 medical centers in the United States, including OHSU. Additional sites will be added during the next several months.
The study hopes to achieve a reduction of 50 percent or more in prostate specific antigen (PSA) levels in patients. PSA is a substance produced within the prostate gland, and a high PSA level may indicate the presence of cancer. In patients with advanced prostate cancer, many clinicians use elevated PSA levels as an indicator of disease progression.
Results from the initial OHSU study were presented by Beer at the American Society of Clinical Oncology conference last May. In that trial, 81 percent (30 of 37) of patients treated with HDPA calcitriol in combination with docetaxel had a reduction in PSA levels of more than 50 percent. Four other studies of docetaxel without calcitriol have reported that 38 percent to 46 percent of the patients had more than a 50 percent reduction in PSA levels, about half the rate as those patients on the combination therapy.
The ASCENT trial is supported by Novacea Inc. (www.novacea.com), in collaboration with Aventis Pharmaceuticals Inc. (www.aventis.com). Novacea has manufactured a new formulation of calcitriol, DN-101, that was specifically designed for use in the HDPA calcitriol treatment of patients with cancer. Aventis is the manufacturer of Taxotere, the brand name of the chemotherapy agent docetaxel.
Prostate cancer is the most common cancer in men, with approximately 189,000 new cases diagnosed and roughly 30,200 deaths in the United States each year (2002 Cancer Facts and Figures, American Cancer Society). The most effective treatment for disseminated prostate cancer is androgen deprivation depletion from surgical or pharmacological means. Treatment options at late stage of illness are extremely limited and include palliative radiotherapy and, in some patients, palliative chemotherapy. Overall, roughly one in six American men will develop prostate cancer during his lifetime. If detected early, however, treatment can be highly effective.
Oregon Health & Science University is a health and research university focused on improving the well-being of people in Oregon and beyond. OHSU educates health practitioners, bioscientists, high-technology professionals, and environmental scientists and engineers, and it undertakes the indispensable functions of patient care, community service and biomedical research.