Randomized, Double-blind Study Comparing Tremelimumab to Placebo in Subjects With Unresectable Malignant Mesothelioma

This is a Phase 2b, randomized, double-blind, parallel-group study. Subjects with unresectable pleural or peritoneal malignant mesothelioma will be randomized in a 2:1 ratio to receive either tremelimumab or placebo. Randomization will be stratified by EORTC status (low-risk vs high-risk), line of therapy (second vs third), and anatomical site (pleural vs peritoneal). This study plans to use the EORTC to stratify subjects into high or low risk groups in order to ensure balanced randomization to the different treatment groups. For subjects in whom pemetrexed was contraindicated or not tolerated or not an approved therapy (eg, peritoneal mesothelioma), prior therapy with a first-line platinum-based regimen is required. Approximately 564 subjects will be enrolled at study centers in multiple countries. The study consists of a screening period, a treatment period, a 90-day follow-up period for safety, and a long-term survival follow-up period.