Multinational phase 2 trial of pembrolizumab monotherapy for high-risk NMIBC without carcinoma in situ and unresponsive to BCG

Cohort B of the multinational phase 2 KEYNOTE-057 trial evaluated pembrolizumab monotherapy in patients with BCG-unresponsive high-risk non-muscle-invasive bladder cancer (NMIBC) without carcinoma in situ who were ineligible for or declined radical cystectomy. Among 132 patients who had received a median of 10 (IQR 9-15) previous BCG instillations, and received a median of 10 cycles (IQR 6-27) of pembrolizumab, the 12-month disease-free survival rate was 43.5% (95% CI 34.9-51.9). Treatment-related adverse events occurred in 73% of patients; 14% had a grade 3 or 4 TRAE, while 13% experienced serious TRAEs. No treatment-related deaths occurred. The authors conclude that pembrolizumab monotherapy showed antitumor activity and manageable toxicity in patients with BCG-unresponsive high-risk NMIBC who declined or were ineligible for radical cystectomy.