title: Low intraindividual variability of cyclosporin A exposure reduces chronic rejection incidence and health care costs.
abstract: The present study applied a receiver operating characteristic (ROC) analysis to assess the role of intraindividual variability of cyclosporin A (CsA) drug exposure in predisposing renal transplant recipients to the occurrence of chronic rejection, as well as to increased health care costs using a resource-based economic analysis. Two hundred and four adult renal transplant recipients were treated with tapering doses of prednisone (Pred) and with a concentration-controlled strategy that selected doses of the olive oil-based formulations of CsA (Sandimmune(R)) that achieved target concentrations based on serial pharmacokinetic profiles. The ROC analysis revealed an inflection point of plots of the coefficient of variation (%CV) of CsA exposure versus the risk of chronic rejection at >/=28.4% for the average concentration (C(av)), i.e., the dosing interval-corrected area under the concentration-time curves, and >/=36% for the trough concentration (C(0)). The incidence of chronic rejection over a period of 5 yr was 24% among the less variable (LV) versus 40% among the variable (V) cohort. The economic analysis revealed that the total mean facility and physician costs per patient were $48,789 versus $60,998, respectively (P < 0.01). The degree of variability displayed by any individual could only be predicted by serial measurements of CsA concentrations, and not by demographic features, laboratory determinations, clinical characteristics, individual or mean values of any observed CsA concentration, or other pharmacokinetic parameters calculated following a single drug exposure. Thus, strategies that reduce intrapatient variability of CsA exposure over time may lead to reductions in chronic allograft loss and in treatment costs.
authors.affiliation: Division of Immunology and Organ Transplantation, Department of Surgery, University of Texas Houston Health Science Center - Medical School, Houston, Texas.
authors.forename: Barry D
authors.initials: BD
authors.lastname: Kahan
authors.affiliation: Division of Immunology and Organ Transplantation, Department of Surgery, University of Texas Houston Health Science Center - Medical School, Houston, Texas.
authors.forename: Maria
authors.initials: M
authors.lastname: Welsh
authors.affiliation: Biometrics Consulting, Houston, Texas.
authors.forename: Diana L
authors.initials: DL
authors.lastname: Urbauer
authors.affiliation: Division of Immunology and Organ Transplantation, Department of Surgery, University of Texas Houston Health Science Center - Medical School, Houston, Texas.
authors.forename: Melinda B
authors.initials: MB
authors.lastname: Mosheim
authors.affiliation: Covance Health Economics and Outcomes Services, Inc., Washington, DC.
authors.forename: Kathleen M
authors.initials: KM
authors.lastname: Beusterien
authors.affiliation: Covance Health Economics and Outcomes Services, Inc., Washington, DC.
authors.forename: Martha R
authors.initials: MR
authors.lastname: Wood
authors.affiliation: Division of Immunology and Organ Transplantation, Department of Surgery, University of Texas Houston Health Science Center - Medical School, Houston, Texas.
authors.forename: Linda P
authors.initials: LP
authors.lastname: Schoenberg
authors.affiliation: Novartis Pharmaceuticals Corporation, East Hanover, New Jersey.
authors.forename: Joseph
authors.initials: J
authors.lastname: Dicesare
authors.affiliation: Division of Immunology and Organ Transplantation, Department of Surgery, University of Texas Houston Health Science Center - Medical School, Houston, Texas.
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Katz
authors.affiliation: Division of Immunology and Organ Transplantation, Department of Surgery, University of Texas Houston Health Science Center - Medical School, Houston, Texas.
authors.forename: Charles T
authors.initials: CT
authors.lastname: VAN Buren
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D019540:Area Under Curve; D015331:Cohort Studies; D016572:Cyclosporine / Q000008:administration & dosage / Q000493:pharmacokinetics*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006084:Graft Rejection / Q000188:drug therapy* / Q000378:metabolism*; D017048:Health Care Costs; D006801:Humans; D007166:Immunosuppressive Agents / Q000008:administration & dosage / Q000493:pharmacokinetics*; D016030:Kidney Transplantation; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011182:Postoperative Care / Q000191:economics*; D011241:Prednisone / Q000008:administration & dosage; D012372:ROC Curve; D012306:Risk; D012680:Sensitivity and Specificity; D018709:Statistics, Nonparametric
chemical_list: D007166:Immunosuppressive Agents; D016572:Cyclosporine; D011241:Prednisone