Ceritinib is a medication primarily used in the treatment of non-small cell lung cancer (NSCLC) that is positive for an abnormal gene called ALK (anaplastic lymphoma kinase). It belongs to a class of drugs known as kinase inhibitors, which work by blocking the activity of specific proteins involved in cancer cell growth and spread. Ceritinib is specifically indicated for patients with ALK-positive metastatic NSCLC who have progressed on or are intolerant to crizotinib, another ALK inhibitor. It is typically taken orally in capsule form.