This is a study of ADI-PEG 20 (pegylated arginine deiminase), an arginine degrading enzyme versus placebo in patients with malignant pleural mesothelioma with low argininosuccinate synthetase 1 expression. Malignant pleural mesothelioma have been found to require arginine, an amino acid. Thus the hypothesis is that by restricting arginine with ADI-PEG 20, the malignant pleural mesothelioma cells will starve and die.