Trial Information

PEG-asparaginase During Two Treatment Courses in the Treatment of Childhood Acute Lymphoblastic Leukemia

Asparaginase is used in the treatment of childhood lymphoblastic leukemia. Approximately 1/3
of the patients develops blocking antibodies against native E.coli asparaginase during the
second exposure, so that they do not benefit from treatment and thus may have a worse
prognosis.

PEG-asparaginase is less immunogenic so that fewer patients may develop antibodies during
the second exposure.

There is no published study about the antibody formation after treatment of children with
PEG-asparaginase during two treatment courses.

The first part of the study is a description of the pharmacokinetics of PEG-asparaginase
after intramuscular administration in order to determine the correct dose.

The second part of the study is a comparison of antibody formation during two treatment
courses after intramuscular administration og native E.coli asparaginase and
PEG-asparaginase.

Other side effects than antibodies will be registered during treatment with
PEG-asparaginase. Finally comparison of the 5-year EFS between the groups (native E.coli
asparaginase and PEG-asparaginase as well as patients who have and have not developed
antibodies) will be evaluated.