A drug that is a form of thalidomide, and is used to treat multiple myeloma that has not gotten better with other anticancer drugs. It is also being studied in the treatment of other types of cancer. Pomalyst 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 immunomodulating agent and a type of antiangiogenesis agent. Also called CC-4047 and pomalidomide.