Mesothelioma is a form of lung cancer strongly associated with exposure to asbestos. Even though asbestos has been banned or heavily regulated in most developed nations, due to delayed onset, the number of mesothelioma cases is predicted to climb until around 2020. In the UK, which has the highest mesothelioma incidence worldwide, two new clinical trials are aiming to find treatments for the disease. The Meso2 trial will investigate ganetespib, while the COMMAND trial will examine defactinib. Defactinib specifically targets cancer stem cells, which often survive cancer treatment and cause cancer recurrence. The drug may therefore help prevent relapse after first-line therapy.