Clinical efficacy and safety of nivolumab in Japanese patients with malignant pleural mesothelioma: 3-year results of the MERIT study

ABSTRACT Introduction We examined the long-term efficacy and safety of nivolumab, a human monoclonal antibody that inhibits interactions between the programmed death-1 (PD-1) receptor and its ligands (PD-L1 and PD-L2), in Japanese patients with malignant pleural mesothelioma (MPM). Methods Japanese patients with previously treated MPM (one or two regimens) were enrolled in a single-arm, Phase II study, and received nivolumab intravenously 240 mg every 2 weeks until progressive disease or unacceptable toxicity. The primary endpoint was the centrally assessed objective response rate (ORR). Other endpoints included overall survival (OS), progression-free survival (PFS), treatment-related adverse events, and patient-reported outcomes (Lung Cancer Symptom Scale for mesothelioma and EuroQOL visual analog scale). Patient enrollment started on June 16, 2016. Here, we report 3-year follow-up data (cutoff date: November 12, 2019). Results Thirty-four patients were enrolled. The centrally assessed ORR was previously reported (29.4%). The 2- and 3-year OS rates were 35.3% and 23.5%, respectively, and the corresponding PFS rates were 17.0% and 12.7%. Median OS and PFS were 17.3 and 5.9 months, respectively. Eight patients were alive at 3 years of follow-up. Nivolumab was well tolerated and no new safety signals were found. The patient-reported outcomes were maintained without significant deteriorations during the study. Conclusions Our results demonstrate clinically relevant long-term efficacy and safety of nivolumab for the treatment of MPM.