A drug used with another drug to treat multiple myeloma in patients who have just been diagnosed. It is also used to treat a painful skin disease related to leprosy. It is 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. It is a type of antiangiogenesis agent and a type of immunomodulating agent. Also called Thalomid.