title: Differences in clearance of mycophenolic acid among renal transplant recipients, hematopoietic stem cell transplant recipients, and patients with autoimmune disease.
abstract: For more than a decade, mycophenolate mofetil (MMF) has been used as an immunosuppressive drug in solid organ transplant recipients to prevent graft rejection. After oral administration, the prodrug MMF is rapidly hydrolyzed to the active metabolite mycophenolic acid (MPA). MMF is being used increasingly in hematopoietic stem cell transplantation (HSCTx) and autoimmune diseases (AID). The pharmacokinetics of MPA are markedly different in these patients. In comparison with renal transplant recipients (RTx), MPA clearance is increased in HSCTx patients and decreased in AIDS. The aim of this study was to characterize MPA clearance in RTx, HSCTx, and AID patients and to test whether the differences in clearance can be described by clinical chemical parameters. MPA concentration-time profiles from 19 RTx patients coprescribed cyclosporine, 17 RTx patients coprescribed tacrolimus, 38 HSCTx patients coprescribed cyclosporine, and 36 patients with AID were analyzed retrospectively with nonlinear mixed effects modeling (first-order conditional estimate). The following covariates were tested: indication for MMF treatment, sex, age, weight, plasma albumin, cyclosporine cotreatment, dose and predose blood concentration, creatinine clearance, and hemoglobin. Pharmacokinetics of MPA were described by a two-compartment model with time-lagged first-order absorption. MPA clearance was correlated in univariate analysis with plasma albumin, cyclosporine dose and predose blood concentration, creatinine clearance, hemoglobin, and indication for MMF treatment (RTx, HSCTx, or AID) (P < 0.001). All significant covariates were combined in an intermediate multivariate model followed by backward elimination. The indication for MMF treatment could be removed from the intermediate model without compromising the fit. The correlation between clearance and cyclosporine predose concentrations and plasma albumin remained significant in the final model and could describe the difference in clearance between the different indications for MMF treatment. Median clearance was 30.2, 45.6, and 10.7 L/h in RTx, HSCTx, and AID patients, respectively. In conclusion, plasma albumin concentrations and cyclosporine predose concentrations are able to describe the difference in MPA clearance among RTx, HSCTx, and AID patients.
authors: Department of Hospital Pharmacy, Clinical Pharmacology Unit, Erasmus University Medical Center, Rotterdam, The Netherlands.
authors: Brenda C M
authors: BC
authors: de Winter
authors: Ron A A
authors: RA
authors: Mathot
authors: Ferdi
authors: F
authors: Sombogaard
authors: Irmgard
authors: I
authors: Neumann
authors: Reinier M
authors: RM
authors: van Hest
authors: Jeanette K
authors: JK
authors: Doorduijn
authors: Teun
authors: T
authors: van Gelder
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019540:Area Under Curve; D001327:Autoimmune Diseases / Q000188:drug therapy*; D016572:Cyclosporine / Q000008:administration & dosage; D004305:Dose-Response Relationship, Drug; D004359:Drug Therapy, Combination; D005260:Female; D006084:Graft Rejection / Q000188:drug therapy / Q000517:prevention & control; D018380:Hematopoietic Stem Cell Transplantation; D006801:Humans; D007166:Immunosuppressive Agents / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D016030:Kidney Transplantation; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D009173:Mycophenolic Acid / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000097:blood / Q000493:pharmacokinetics; D012709:Serum Albumin / Q000032:analysis; D016559:Tacrolimus / Q000008:administration & dosage
chemical_list: D007166:Immunosuppressive Agents; D012709:Serum Albumin; D016572:Cyclosporine; D009173:Mycophenolic Acid; D016559:Tacrolimus