A simultaneous d-optimal designed study for population pharmacokinetic analyses of mycophenolic Acid and tacrolimus early after renal transplantation.
Mycophenolic acid (MPA) and tacrolimus (TAC) are immunosuppressive agents used in combination with corticosteroids for the prevention of acute rejection after solid organ transplantation. Their pharmacokinetics (PK) show considerable unexplained intraindividual and interindividual variability, particularly in the early period after transplantation. The main objective of the present work was to design a study based on D-optimality to describe the PK of the 2 drugs with good precision and accuracy and to explain their variability by means of patients' demographics, biochemical test results, and physiological characteristics. Pharmacokinetic profiles of MPA and TAC were obtained from 65 stable adult renal allograft recipients on a single occasion (ie, day 15 after transplantation). A sampling schedule was estimated based on the D-optimality criterion with the POPED software, using parameter values from previously published studies on MPA and TAC modeling early after transplantation. Subsequently, a population PK model describing MPA and TAC concentrations was developed using nonlinear mixed-effects modeling. Optimal blood-sampling times for determination of MPA and TAC concentrations were estimated to be at 0 (predose) and at 0.24, 0.64, 0.98, 1.37, 2.38, and 11 hours after oral intake of mycophenolate and TAC. The PK of MPA and TAC were best described by a 2-compartment model with first-order elimination. For MPA, the absorption was best described by a transit compartment model, whereas first-order absorption with a lag time best described TAC transfer from the gastrointestinal tract. Parameters were estimated with good precision and accuracy. While hematocrit levels and CYP3A5 genetic polymorphism significantly influenced TAC clearance, the pharmaceutical formulation and MRP2 genetic polymorphism were retained as significant covariates on MPA absorption and elimination, respectively. The prospective use of the simultaneous D-optimal design approach for MPA and TAC has allowed good estimation of MPA and TAC PK parameters in the early period after transplantation characterized by a very high unexplained variability. The influence of some relevant covariates could be shown.
Louvain Drug Research Institute, Louvain Centre for Toxicology and Applied Pharmacology, LDRI/PKDM B1.73.13, Av. E. Mounier 73, 1200 Bruxelles, Belgique. flora.musuamba@uclouvain.be
Flora Tshinanu
FT
Musuamba
Michel
M
Mourad
Vincent
V
Haufroid
Martine
M
Demeyer
Arnaud
A
Capron
Isabelle K
IK
Delattre
Frederic
F
Delaruelle
Pierre
P
Wallemacq
Roger Karel
RK
Verbeeck
D000284:Administration, Oral; D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D051544:Cytochrome P-450 CYP3A / Q000235:genetics; D005260:Female; D005838:Genotype; D006400:Hematocrit; D006801:Humans; D007166:Immunosuppressive Agents / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D016030:Kidney Transplantation / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D000089762:Multidrug Resistance-Associated Protein 2; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000235:genetics; D009173:Mycophenolic Acid / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D016559:Tacrolimus / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D055815:Young Adult
D051544:Cytochrome P-450 CYP3A; D007166:Immunosuppressive Agents; D000089762:Multidrug Resistance-Associated Protein 2; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D009173:Mycophenolic Acid; D016559:Tacrolimus; C000715087:ABCC2 protein, human; C510164:CYP3A5 protein, human