L-asparaginase

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L-asparaginase is a chemotherapy agent used for treatment of canine lymphoma.

Pharmacologic quantities of L-asparaginase are isolated from Escherichia coli and Erwinia carotovora and sold as 99.9% pure, endotoxin-free lyphophilized powder. L-asparaginase is inherently a foreign protein and as such can produce an anaphylactic reaction.

L-asparaginase exploits the unusually high requirement tumor cells have for the amino acid asparagine. Asparagine is an amino acid required by cells for the production of protein. Asparagine can be produced within a cell through the enzyme asparagine synthetase or it can absorbed into the cell from the outside (i.e. it is consumed in the patient’s diet, absorbed into the body and made available to the body’s cells.) Tumor cells, more specifically lymphatic tumor cells, require huge amounts of asparagines to keep up with their rapid, malignant growth. This means they use both asparagine from the diet as well as what they can make themselves (which is limited) to satisfy their large asparagines demand.

L-asparaginase and methotrexate work against each other and should be administered at least 48 hours apart.

Success rates in lymphoma are low (approx 30%) when used as a sole agent, but higher when used in combination with chlorambucil, prednisolone or cyclophosphamide.

Side effects are common, and pancreatitis appears to a rare complication in some dogs[1].

Dose rate for use in dogs is 400 U/kg IV, IP, IM weekly

References

  1. Schleis SE et al (2011) Asparaginase-associated pancreatitis in a dog. Can Vet J 52(9):1009-1012