ORLANDO, FL, USA (UroToday.com) - In this study, as of September 14, 2012, 7 patients received an infusion of sipuleucel-T. These patients had progressed to mCRPC and had been previously treated with at least one infusion of sipuleucel-T on the PROTECT trial. The median interval since the last infusion had been 8.6 years. This is the first study to demonstrate an immunological memory response of several years after initial treatment in patients being retreated with sipuleucel-T. The retreatment was well tolerated and the antigen-specific cellular responses were boosted after retreatment.