A drug used to treat acute lymphoblastic leukemia (ALL). It is a form of the anticancer drug PEG-asparaginase that stays in the body longer. Oncaspar-IV is an enzyme that breaks down the amino acid asparagine and may block the growth of tumor cells that need asparagine to grow. It is a type of protein synthesis inhibitor. Also called EZN-2285 and SC-PEG E. coli L-asparaginase.