Cancer patients taking calcitriol, the activated form of Vitamin D experience a reduction in blood clots an Oregon Health & Science University Cancer Institute team has found. The results of the clinical trial recently was published online in the British Journal of Haematology and in the November print issue, Saturday, Oct. 16.

Thrombosis, or blood clots, is a serious complication in advanced cancers and affects between 15 and 20 percent of all cancer patients.

"Blood clots, including life-threatening events such as stroke, heart attacks and blood clots in the lungs are serious complications of advanced cancer and cancer chemotherapy.  Reducing such blood clots would make a big difference for cancer patients," said Tomasz M. Beer, M.D., director of the Prostate Cancer Program in the OHSU Cancer Institute and principal investigator of the study, which involved researchers from the United States and Canada.

In a randomized trial involving 250 patients with advanced prostate cancer in 48 clinical sites, those receiving high-dose calcitriol (DN-101) along with Docetaxel experienced a significant reduction in both venous and arterial thromboses compared with patients receiving a placebo and Docetaxel.

Calcitriol is a naturally occurring hormone and the biologically active form of Vitamin D.

While the clinical trial involved patients with advanced stages of prostate cancer, in vitro studies of myelogenous leukemia cells, monocytes and osteoblasts, and observation in mice demonstrate that high concentrations of vitamin D can reduce activation of the clotting system and suggest that vitamin D could help reduce blood clots in a wide range of cancers.

The reduction in blood clots was not anticipated and was found in an exploratory analysis of AIPC Study of Calcitriol Enhancing Taxotere (ASCENT.)  Thus, it must be confirmed in a prospective study. ASCENT-2, an international study that compares docetaxel with prednisone to docetaxel with DN-101 will prospectively test the ability of high dose calcitriol to reduce blood clots in cancer patients. If these benefits are confirmed, high dose calcitriol would become a convenient and safe method for preventing blood clots in prostate cancer patients on chemotherapy, according to Beer.

DN-101 is produced by Novacea Inc. OHSU and Beer have significant financial interest in Novacea, Inc., a company that has a commercial interest in the results of this research and technology. This potential conflict was reviewed and a management plan approved by the OHSU Conflict of Interest in Research Committee and the Integrity Program Oversight Council was implemented.