A drug used with dexamethasone to treat multiple myeloma in patients who have been just diagnosed. It is also used to treat a painful skin disease related to leprosy. It is also being studied in the treatment of other types of cancer. Thalidomide may help the immune system kill cancer cells. It may also prevent the growth of new blood vessels that tumors need to grow. Thalidomide is a type of antiangiogenesis agent and a type of immunomodulating agent. Also called Thalomid.