Ad.hIFN-α (SCH 721015, adenoviral-mediated interferon alpha) is a replication-defective recombinant adenoviral vector containing the human interferon-alpha (hIFN-alpha) gene. This Phase I study is designed to evaluate the safety and maximum tolerated dose (MTD) of two doses of Ad.hIFN-alpha injected into the pleural (intrapleural, IP) and given 4 days apart in subjects with pleural mesothelioma.