This multicenter trial is evaluating the mesothelin-targeting antibody-drug conjugate, anetumab ravtansine in subjects with thymic carcinoma. This clinical trial is based on a preclinical study conducted by our group that showed strong, membranous expression of mesothelin in thymic carcinoma. Three patients have been enrolled and treated with anetumab. One patient experienced a durable complete response and two patients had durable stabilization of disease. Adverse events associated with anetumab were manageable and included peripheral neuropathy and development of corneal microcysts, which are reversible with interruption of treatment.