(UroToday.com) KEYNOTE-199 is a multicohort phase 2 study to evaluate pembrolizumab in mCRPC. A previous analysis of patients with RECIST-measurable (cohort 4) or bone-predominant nonmeasurable (cohort 5) disease who were chemotherapy-naive and had progression while on enzalutamide found that pembrolizumab + enzalutamide showed antitumor activity and manageable safety. Long-term outcomes are of interest with immunotherapy, and as such, at the ASCO 2021 annual meeting, Dr. Julie Graff and colleagues presented results of the updated efficacy and safety data after an additional 1 year of follow-up.