**4.2 Nivolumab**

Nivolumab is a fully humanized monoclonal anti-PD-1 antibody. It was first tested in 34 patients with recurrent MPM in the Netherlands [23]. In that singlecenter trial, patients with MPM received 3 mg/kg intravenous nivolumab every 2 weeks. Among 34 patients, 8 patients (24%) achieved a partial response, and another 8 patients (24%) displayed stable disease at 12 weeks.

A Japanese group also evaluated the efficacy and safety of nivolumab in 34 patients with advanced MPM. That study tested nivolumab as a salvage therapy in a single-arm phase II study (MERIT study) [24]. Patients received 240 mg nivolumab intravenously every 2 weeks. Ten (29%) patients showed an objective response. The median duration of the response was 11.1 months, and the disease control rate was 68%. The median PFS and OS were 6.1 and 17.3 months, respectively. Among patients with PD-L1-positive tumors (≥1% expression), the ORR was 40%. Based on those results, nivolumab was approved in Japan for unresectable recurrent MPM.
