Japan's Astellas Pharma Inc. and U.S. pharmaceutical giant Pfizer Inc. said combining their cancer drug Xtandi with androgen deprivation therapy in a late-stage clinical study extended the life of patients while keeping the disease at bay.

The 1,150 patients in the study, named Arches, had prostate cancer that had spread to other parts of the body and was still responsive to medical or surgical treatment, a condition called metastatic hormone-sensitive prostate cancer.

In top-line results, the men who received both the drug and the therapy lived longer without disease worsening than those who received only the therapy. Androgen deprivation therapy depletes the body of the hormone that causes prostate cancer cells to grow.

Xtandi inhibits the receptors that accept the group of hormones known as androgens.

New York's Pfizer markets Xtandi in the U.S. with Astellas, which sells the drug in all other countries it is approved. In late October, the drug had its most recent regulatory win in Europe for men with high-risk, non-metastatic castration-resistant prostate cancer.