Pegylated L-asparagine amidohydrolase from E. coli. Pegylation significantly (via a element of four) extends the protein half life.
In a significant number of patients with acute leukemia, the malignant cells are dependent on an exogenous source of asparagine for survival. Normal cells, however, are able to synthesize asparagine and thus are affected less by the rapid depletion produced by treatment with the enzyme asparaginase. Oncaspar exploits a metabolic defect in asparagine synthesis of some malignant cells.
For treatment of acute lymphoblastic leukemia
Pegaspargase, more effective than asparaginase, converts asparagine to aspartic acid and ammonia. It facilitates production of oxaloacetate which is needed for general cellular metabolism. Some malignant cells lose the ability to produce asparagine and so the loss of exogenous sources of asparagine leads to cell death.