title: Pharmacokinetic, pharmacodynamic and intracellular effects of PEG-asparaginase in newly diagnosed childhood acute lymphoblastic leukemia: results from a single agent window study.
abstract: L-asparaginase is an effective drug for treatment of children with acute lymphoblastic leukemia (ALL). The effectiveness is thought to result from depletion of asparagine in serum and cells. We investigated the clinical response in vivo of 1000 IU/m(2) pegylated (PEG)-asparaginase and its pharmacokinetic, pharmacodynamic and intracellular effects in children with newly diagnosed ALL before start of combination chemotherapy. The in vivo window response was significantly related to immunophenotype and genotype: 26/38 common/pre B-ALL cases, especially those with hyperdiploidy and TELAML1 rearrangement, demonstrated a good clinical response compared to 8/17 T-ALL (P=0.01) and BCRABL-positive ALL (P=0.04). A poor in vivo clinical window response was related to in vitro resistance to L-asparaginase (P=0.02) and both were prognostic factors for long-term event-free survival (hazard ratio 6.4, P=0.004; hazard ratio 3.7, P=0.01). After administration of one in vivo dose of PEG-asparaginase no changes in apoptotic parameters or in intracellular levels of twenty amino acids in leukemic cells could be measured, in contradiction to the changes found after in vitro exposure. This may be explained by the rapid removal of apoptotic cells from the circulation in vivo. One additional dose of PEG-asparaginase upfront ALL treatment did not lead to other severe toxicities.
authors.affiliation: Department of Pediatric Oncology/Hematology, Erasmus MC/Sophia Children's Hospital, Erasmus University Medical Center, Rotterdam, The Netherlands. i.m.appel@erasmusmc.nl
authors.forename: I M
authors.initials: IM
authors.lastname: Appel
authors.forename: K M
authors.initials: KM
authors.lastname: Kazemier
authors.forename: J
authors.initials: J
authors.lastname: Boos
authors.forename: C
authors.initials: C
authors.lastname: Lanvers
authors.forename: J
authors.initials: J
authors.lastname: Huijmans
authors.forename: A J P
authors.initials: AJ
authors.lastname: Veerman
authors.forename: E
authors.initials: E
authors.lastname: van Wering
authors.forename: M L
authors.initials: ML
authors.lastname: den Boer
authors.forename: R
authors.initials: R
authors.lastname: Pieters
mesh_terms: D000596:Amino Acids / Q000032:analysis / Q000187:drug effects; D017209:Apoptosis / Q000187:drug effects; D001215:Asparaginase / Q000008:administration & dosage / Q000493:pharmacokinetics* / Q000633:toxicity; D002648:Child; D005838:Genotype; D006801:Humans; D016130:Immunophenotyping; D011092:Polyethylene Glycols; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000188:drug therapy* / Q000401:mortality / Q000473:pathology; D011379:Prognosis; D016019:Survival Analysis; D016896:Treatment Outcome
chemical_list: D000596:Amino Acids; D011092:Polyethylene Glycols; D001215:Asparaginase