(UroToday.com) PURE-01 was an open-label, single-arm, phase 2 trial where three courses of 200mg pembrolizumab were administered in T2-4aN0M0 bladder cancer patients preceding radical cystectomy (RC).1 A proportion of these patients had residual invasive disease (ypT2-4) at radical cystectomy. Investigators from Fondazione IRCCS Istituto Nazionale dei Tumori explored the biological characteristics of pembrolizumab-resistant tumors in the context of this trial.