First response evaluation was done in all 27 patients. Overall response rate was 32% (3 patients with CR and 5 patients PR). Median progression free survival (PFS) was 4 months...Median PFS of patients with loss BAP1 signature was significantly longer than BAP1 intact or unknown patients (Not reached vs 2.9 months, p=0.0387)...The ipilimumab and nivolumab combination therapy seems to be a well-tolerable treatment option for particularly for patients with MPM with BAP1 signature loss.