Post-marketing Surveillance Study of the Pharmacokinetics of Asparaginase and Antibody Formation in Interfant-06

Combination chemotherapy for acute lymphoblastic leukaemia (ALL) usually includes a bacterial L-asparaginase enzyme derived from Escherichia coli or Erwinia species. Several studies have described the pharmacokinetics in children above 1 year of age of asparaginase given intramuscularly as well as intravenously. The development of anti-asparaginase antibodies to these foreign proteins has also been described.

Chemotherapy for infant ALL also includes L-asparaginase. However, the pharmacokinetics of asparaginase and antibody formation in infants is needed to be described to optimize therapy for this group of patients who have a doubtful prognosis.

Background In general the information about drug metabolism in neonates and infants is scarce as well as the reactions of an immature immune system to foreign proteins. Several pharmacokinetic studies have been performed in children above one year of age, but no data is available about pharmacokinetics and antibody formation during treatment with any asparaginase preparation in infants.

Pharmacokinetics:

Asparaginase is used in the treatment of childhood ALL since it depletes the blood of asparagines, which can be synthesized by normal cells but not by leukemic lymphoblasts. It has been shown that serum activities above 100 IU/l ensure depletion of asparagine in serum and CNS. In many cases even values considerably lower than 100 IU/l will deplete asparagine from the serum1-5.