 A few months later the U.S. Food and Drug Administration (FDA) agreed to review the vaccine on an accelerated schedule when the company filed for approval, and Antigenics began recruiting 728 patients with kidney cancer for the phase 3 trial, the largest study conducted in the world.Ultimately, 118 cancer centers participated in the trial, 63 of them outside the U.S..The largest group of patients, 172, was treated in Russia.