title: Pentostatin pharmacokinetics and dosing recommendations in patients with mild renal impairment.
abstract: OBJECTIVE
  The purpose of this study was to determine the pharmacokinetic parameters of pentostatin in renally impaired patients in order to establish dosing guidelines for this population.
  
  
  METHODS
  Pentostatin doses were administered as 15-min intravenous infusions to patients based on their measured creatinine clearance (CLcr) as follows. Patients with normal renal function (NRF), defined as CLcr >60 ml/min, received 4 mg/m(2) repeated every14 days. Patients with impaired renal function (IRF) included those with CLcr 41-60 ml/min who received 3 mg/m(2) and those with CLcr 21-40 ml/min who received 2 mg/m(2), also repeated every 14 days. Heparinized plasma samples were collected during drug infusion and out through 96 h after dosing, except in two patients in whom sampling was extended to 144 h after dosing. Urine sampling extended to 96 h after dosing, and all samples were analyzed by a validated enzyme immunoassay for pentostatin concentrations.
  
  
  RESULTS
  Enrolled in the study were 13 patients (7 IRF and 6 NRF), of whom 12 contributed samples for pharmacokinetic analysis. Median baseline CLcr values were 71.5 ml/min for NRF patients and 44 ml/min for IRF patients. Following the end of intravenous infusion, pentostatin plasma concentrations declined biexponentially with time. In some patients there was a transient increase in pentostatin equivalents 2 to 4 h after dosing. There was a good correlation between measured CLcr and pentostatin total plasma clearance. The AUC(0- infinity ) values seen in IRF patients, at lower doses, were within the range of the AUC(0- infinity ) values seen in patients with normal CLcr. Toxicities observed in the two groups of patients were similar.
  
  
  CONCLUSIONS
  The pentostatin doses used in the study appear to be appropriate for administration to cancer patients with varying degrees of renal impairment.
authors.affiliation: Bayer Corporation, 400 Morgan Lane, West Haven, CT 06516, USA. chetan.lathia.b@bayer.com
authors.forename: Chetan
authors.initials: C
authors.lastname: Lathia
authors.forename: Gini F
authors.initials: GF
authors.lastname: Fleming
authors.forename: Mark
authors.initials: M
authors.lastname: Meyer
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Ratain
authors.forename: Lloyd
authors.initials: L
authors.lastname: Whitfield
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000964:Antimetabolites, Antineoplastic / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics* / Q000652:urine; D019540:Area Under Curve; D003404:Creatinine / Q000097:blood; D004791:Enzyme Inhibitors / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics* / Q000652:urine; D005260:Female; D006801:Humans; D007674:Kidney Diseases / Q000378:metabolism*; D008297:Male; D008657:Metabolic Clearance Rate; D008875:Middle Aged; D009369:Neoplasms / Q000150:complications / Q000188:drug therapy* / Q000378:metabolism; D015649:Pentostatin / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics* / Q000652:urine
chemical_list: D000964:Antimetabolites, Antineoplastic; D004791:Enzyme Inhibitors; D015649:Pentostatin; D003404:Creatinine