L-asparaginase Assay for Leukemia Canine Patients
The L-asparaginase assay is a laboratory developed test (LDT) to determine the enzyme activity of L-asparaginase in patients who have been treated with asparaginase drug products. The assay was fully validated and is performed in a high complexity laboratory.
The L-asparaginase activity test can help physicians identify patients experiencing “silent inactivation” as well as to ensure that adequate asparaginase activity is present during asparaginase treatment. The assay is performed using a serum sample obtained from the patient after treatment. A minimal volume of sample (0.2 mL) is required, and the results are returned within one business day.
What is L-asparaginase?
Asparginase, an enzyme produced by bacteria, is used as an anti-neoplastic agent to treat cancer known to affect the immune system, but in dogs is mostly used to treat lymphoma. The mechanism of action is inhibition of asparagine in cancer cells. Asparagine is a non-essential amino acid, meaning that normal cells can produce asparagine through its innate biochemical pathways.
Asparagine is needed by all cells as an important part of its protein structures. Cells without asparagine will die. Asparaginase removes asparagine outside of the cancer cells limiting the cells to the available asparagine already in the cells. Like all chemotherapeutic and anti-neoplastic agents, asparaginase is not without side effects. The most common adverse reactions are hypersensitivity and sub-clinical hypersensitivity (silent inactivation). Silent inactivation occurs when patients develop anti-asparaginase antibodies without clinical signs of hypersensitivity. These patients suffer greater incidence of cancer relapse. Therapeutic drug monitoring through measurement of asparaginase enzyme activity can identify patients at risk for silent inactivation.