A drug used with other anticancer drugs to treat acute lymphoblastic leukemia (ALL). It is an enzyme that comes from the Erwinia chrysanthemi bacterium. It is used in patients who cannot take a similar drug that comes from the E. coli bacterium. It is also being studied in the treatment of other types of cancer. It breaks down the amino acid asparagine and may block the growth of cancer cells that need asparagine to grow. It may also kill cancer cells.