April 8, 2009
Prostate Drug Shows Promise
Researchers report that a prostate cancer drug which takes a new approach to blocking tumor growth, helped more than 40 percent of men with advanced prostate cancer.
The drug, made by San Francisco-based Medivation Inc., helps stop testosterone from getting into cells and driving the cancer.
The findings were published in the journal Science.
Of the first 30 patients treated with MDV3100, 13 showed declines of more than 50 percent in the levels of chemicals in the blood that indicate the presence of the cancer.
Dr. Chris Tran of Memorial Sloan-Kettering Cancer Center in New York and colleagues led the study.
They warn that the tests are only in phase 1 and 2, where drugs are checked for safety, side effects, and effectiveness. More tests are necessary before the drug can be sold.
The treatment is for prostate cancer that has already spread to other areas of the body.
Men with advanced prostate cancer are often treated with so-called castration therapy -- drugs that block the production of testosterone, the "male" hormone that drives many prostate tumors.
But the cancer cells begin to evade this treatment in many men. The researchers looked for a drug that might work despite this mutation by the cancer cells.
They settled on MDV3100, which worked well in mice.
"Of the first 30 patients treated with MDV3100 in a phase I/II clinical trial, 13 of 30 (43 percent) showed sustained declines (by more than 50 percent) in serum levels of prostate specific antigen, a biomarker of prostate cancer," they wrote.
Lower levels of PSA suggest that tumors have stopped growing or have shrunk.
Prostate cancer kills about 254,000 men a year globally, 29,000 in the United States alone.
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