Used in the treatment of non-small cell lung cancer (NSCLC) that is caused by abnormalities in the ALK or ROS1 genes. It works by blocking the action of abnormal proteins that signal cancer cells to grow, helping to slow or stop the spread of cancer. Often prescribed for patients with advanced or metastatic disease, it is taken orally and can lead to significant tumor shrinkage in responsive patients. Also investigated for use in other cancers involving ALK or ROS1 mutations, such as neuroblastoma and inflammatory myofibroblastic tumors.