Iclusig is among only a handful of drugs used in the treatment of leukemia and is part of the class of Kinase inhibitors. Kinase inhibitors are also used to treat cancers such as melanoma, lung cancer, renal cancer and breast cancer and are used in certain instances to treat rheumatoid arthritis or prevent organ transplant rejection. Kinase inhibitors work by stopping the growth of cancer cells and preventing the spread of those cells. More specifically, Iclusig is a tyrosine-kinase inhibitor, meaning it disrupts enzymes within cancer cells. Iclusig is prescribed for those patients whose particular cancers are hard-to-treat or impervious to other forms of treatment including other tyrosine-kinase inhibitor drugs.