Imatib 400mg tablet contains the active substance imatinib. It is an antineoplastic drug that belongs to the class tyrosine kinase inhibitor. This tablet is used in treating adults and children with chronic myeloid leukemia (CML- it is a form of leukemia in which certain abnormal white blood cells start growing out of control). It is also indicated to treat Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph-positive ALL). It is also used to treat certain types of gastrointestinal stromal tumors (GIST, a type of tumor that grows in the walls of the digestive passages and may spread to other parts of the body).