Anti-PD-L1 antibody MPDL3280A is well-tolerated and associated with clinical activity in patients with metastatic bladder cancer, according to the results of a phase I study presented at ASCO. The objective response rate in 20 evaluable patients, measured using RECIST criteria, was 50% (one complete response, nine partial responses), with a median time to response of 43 days. Patients who progressed had higher levels of IL8 and CCL2 in their tumours prior to treatment.