Experimental drug promising for prostate

ROCHESTER, Minn., June 19 (UPI) -- Two patients with inoperable prostate cancer are cancer free, thanks in part to an experimental drug, U.S. doctors say.

The Mayo Clinic physicians say this new approach caused the tumors to shrink dramatically and allowed surgery. In both cases, the aggressive tumors had grown well beyond the prostate into the abdominal areas.

The two patients were participating in a clinical trial of an immunotherapeutic agent called MDX-010, or ipilimum, which was used in combination with standardized hormone treatment and radiation therapy.

"The goal of the study was to see if we could modestly improve upon current treatments for advanced prostate cancer," clinical trial leader Dr. Eugene Kwon says in a statement. "The candidates for this study were people who didn't have a lot of other options. However, we were startled to see responses that far exceeded any of our expectations."

After androgen ablation -- a hormone therapy that removes testosterone and usually causes tumor shrinkage -- the patients received a single dose of the new drug, an antibody that builds on the anti-tumor action of the hormone and causes a much larger immune response.

"The tumors had shrunk dramatically," Dr. Michael Blute, who operated on both men, said. "I had never seen anything like this before. I had a hard time finding the cancer."