CD274 and neoplasm: A second multicenter phase II study (SWOG S1605) also reported positive results with systemic atezolizumab, a humanized IgG1 monoclonal antibody that targets PD-L1, administered every three weeks for 12 months in 129 BCG-unresponsive NMIBC (including 74 CIS ± Ta/T1 tumor and 55 papillary tumors without CIS).