The results of the trial were published in the New England Journal of Medicine.
Avratronone, also known as Xetega, is a hormone therapy.
Avratiron, the opposite of chemotherapy that kills cancer cells, prevents more testosterone from reaching the prostate gland to stifle tumor growth.
The trial included nearly 2,000 patients.
Half of the men were treated with hormones, while the other half received hormone therapy and Avratronone.
Of the 1,917 men in the trial, 184 died in the mixed group compared with 262 in the hormone-only group.
Professor Nicholas James of the University of Birmingham, who led the research, says: "Epreation is actually used to treat some men who have spread the disease in their bodies but our results show a lot of men can benefit."
Each year about 46,500 men are diagnosed with prostate cancer in Britain, and about 11,000 people die from the disease.