AstraZeneca, a British multinational pharmaceutical and biologics company headquartered in London, UK, announced that the FDA has granted Orphan Drug Designation (ODD) for its tremelimumab for the treatment of malignant mesothelioma. Malignant mesothelioma is a rare form of cancer originated from cells lining many of the internal organs of the body and asbestos exposure has been identified as one of the major risk factors for this type of cancer. The prognosis for malignant mesothelioma remains poor and treatment options and effectiveness are limited. Tremelimumab is a humanized monoclonal antibody against CTLA-4, which is expressed on the surface of activated T lymphocytes and inhibits their cytotoxic effect on cancer cells. By blocking the binding of ligands to CTLA-4, tremelimumab reactivates the immune system to destroy cancer cells. In addition to being evaluated as a monotherapy treatment for patients with mesothelioma, tremelimumab is currently being investigated as combination therapy in non-small cell lung cancer and head and neck cancer.