| Noun | 1. | melphalan - antineoplastic drug (trade name Alkeran) used to treat multiple myeloma and some other malignanciesantineoplastic, antineoplastic drug, cancer drug - any of several drugs that control or kill neoplastic cells; used in chemotherapy to kill cancer cells; all have unpleasant side effects that may include nausea and vomiting and hair loss and suppression of bone marrow function |