title: Clinical pharmacology of polyethylene glycol-L-asparaginase.
abstract: Polyethylene glycol (PEG)-L-asparaginase, at doses ranging from 500 to 8000 units/m2, was infused iv over 60 min in 31 patients of whom 27 were evaluable pharmacokinetically. The plasma disappearance of PEG-L-asparaginase is described by a monophasic curve with a mean half-life of 357 +/- 243 hr which is much longer than that of the unconjugated enzyme (half-life of approximately 20 hr). The rate of total clearance (128 +/- 74 ml/m2 X day) is much slower than that of L-asparaginase (2196 +/- 1098 ml/m2 X day). The volume of distribution is 2093 +/- 643 ml/m2, which is similar to that of L-asparaginase, indicating that PEG-L-asparaginase is mainly localized in the plasma. No enzyme could be measured in urine samples taken from nine patients for a period of up to 4 days. Additionally, no enzyme was measurable in one patient's pleural fluid obtained at the end of infusion and 6 days after infusion of a 1000-unit/m2 dose; the corresponding concentrations in plasma were 0.64 and 0.62 units/ml, respectively. In general, the plasma enzyme concentrations at the end of the 1-hr infusion and at 14 days after drug administration were proportional to the dose given. However, in two patients, a sudden disappearance of enzyme levels occurred which preceded anaphylactic reactions during subsequent treatment. A third patient developed severe bronchospasm 30 min after the first dose, but his enzyme levels were within the normal range.
authors.forename: D H
authors.initials: DH
authors.lastname: Ho
authors.forename: N S
authors.initials: NS
authors.lastname: Brown
authors.forename: A
authors.initials: A
authors.lastname: Yen
authors.forename: R
authors.initials: R
authors.lastname: Holmes
authors.forename: M
authors.initials: M
authors.lastname: Keating
authors.forename: A
authors.initials: A
authors.lastname: Abuchowski
authors.forename: R A
authors.initials: RA
authors.lastname: Newman
authors.forename: I H
authors.initials: IH
authors.lastname: Krakoff
mesh_terms: D000328:Adult; D000368:Aged; D000707:Anaphylaxis / Q000139:chemically induced; D001215:Asparaginase / Q000008:administration & dosage / Q000378:metabolism / Q000494:pharmacology* / Q000627:therapeutic use / Q000652:urine; D004305:Dose-Response Relationship, Drug; D004341:Drug Evaluation; D005260:Female; D006801:Humans; D007263:Infusions, Parenteral; D007700:Kinetics; D007945:Leukemia, Lymphoid / Q000188:drug therapy; D007951:Leukemia, Myeloid / Q000188:drug therapy; D015470:Leukemia, Myeloid, Acute / Q000188:drug therapy; D008223:Lymphoma / Q000188:drug therapy; D008297:Male; D008875:Middle Aged; D011092:Polyethylene Glycols / Q000008:administration & dosage / Q000378:metabolism / Q000494:pharmacology* / Q000627:therapeutic use / Q000652:urine
chemical_list: D011092:Polyethylene Glycols; C042705:pegaspargase; D001215:Asparaginase