According to researchers from the University of Michigan Comprehensive Cancer Center, Ann Arbor, Michigan men with advanced prostate cancer experienced significant and rapid positive effects from an investigational treatment known as cabozantinib.

In a n article published online in the Journal of Clinical Oncology (Nov. 19, 2012) approximately two-thirds of men who were treated with cabozantinib had improvements on their bone scans, with 12% seeing complete resolution of uptake on their bone scans.
“The effects of cabozantinib on bone scans are unprecedented in the treatment of prostate cancer,” said lead study author David C. Smith, MD.

Cabozantinib had the most significant effect on tumors of the bones. What is very significant is that cabozantinib is aslready FDA approved for use in thyroid cancer under the brand name Cometriq, but its use in prostate cancer is still considered investigational. Given is fact, if ever presented to the FDA for approval as a treatment to fight advanced prostate cancer it should be easier to obtain approval as it has already been accepted as a safe drug. All it would need to prove is its efficacy.

Besides the improvements on bone scans, 67% of men with bone pain reported an improvement in pain control and 56% decreased or eliminated narcotic painkillers after treatment with cabozantinib.

The phase II trial, which consisted of171 men with castration-resistant advanced prostate cancer, began as a randomized trial in which all men receiving cabozantinib for 12 weeks, after which men were randomized to receive continued cabozantinib or placebo. The randomization was stopped early because of the dramatic effects on bone scan and because the men receiving placebo saw their cancer progress much more quickly than those who remained on drug.

Among the 31 men who were randomized, cancer progressed after a median 23.9 weeks for men taking cabozantinib, compared with 5.9 weeks for those on placebo.

Phase III trials have begun. Researchers at the University of Michigan are also conducting a phase II study to better understand the effect cabozantinib has on bone.

Joel T. Nowak, M.A., M.S.W.