Tacrolimus Dose-adjusted Trough Concentration Research Articles

Composite CYP3A (CYP3A4 and CYP3A5) phenotypes and influence on tacrolimus dose adjusted concentrations in adult heart transplant recipients.

CYP3A5 genetic variants are associated with tacrolimus metabolism. Controversy remains on whether CYP3A4 increased [*1B (rs2740574), *1 G (rs2242480)] and decreased function [*22 (rs35599367)] genetic variants provide additional information. This retrospective cohort study aims to address whether tacrolimus dose-adjusted trough concentrations differ between combined CYP3A (CYP3A5 and CYP3A4) phenotype groups. Heart transplanted patients (n = 177, between 2008 and 2020) were included and median age was 54 years old. Significant differences between CYP3A phenotype groups in tacrolimus dose-adjusted trough concentrations were found in the early postoperative period and continued to 6 months post-transplant. In CYP3A5 nonexpressers, carriers of CYP3A4*1B or *1 G variants (Group 3) compared to CYP3A4*1/*1 (Group 2) patients were found to have lower tacrolimus dose-adjusted trough concentrations at 2 months. In addition, significant differences were found among CYP3A phenotype groups in the dose at discharge and time to therapeutic range while time in therapeutic range was not significantly different. A combined CYP3A phenotype interpretation may provide more nuanced genotype-guided TAC dosing in heart transplant recipients.

Effect of CYP3A4*22, CYP3A5*3 and POR*28 genetic polymorphisms on calcineurin inhibitors dose requirements in early phase renal transplant patients.

This study aimed to investigate the combined effect of CYP3A5*3, CYP3A4*22, and POR*28 genetic polymorphisms on tacrolimus and cyclosporine dose requirements. One hundred thirty renal transplant patients placed on either tacrolimus or cyclosporine were recruited, where the effect of CYP3A5*3, CYP3A4*22, and POR*28 genetic polymorphisms on their dose requirements were studied at days 14, 30, and 90 post-transplantations. The POR*28 allele frequency in the studied population was 29.61%. The tacrolimus dose-adjusted trough concentration ratio (C0/D) was significantly lower in the fast metabolizers group ( CYP3A5*1/POR*28(CT/TT ) carriers) than in the poor metabolizers group ( CYP3A5*3/*3/CYP3A4*22 carriers) throughout the study (14, 30, and 90 days) ( P = 0.001, <0.001, and 0.003, respectively). Meanwhile, there was no significant effect of this gene combination on cyclosporine C0/D. Combining the CYP3A5*3, POR*28 , and CYP3A4*22 genotypes can have a significant effect on early tacrolimus dose requirements determination and adjustments. However, it does not have such influence on cyclosporine dose requirements.

#3185 INFLUENCE OF COMBINED CYP 3A4/5 AND POR*28 GENETIC POLYMORPHISMS ON TACROLIMUS AND CCLOSPORINE DOSE REQUIREMENTS IN INCIDENT RENAL TRANSPLANT PATIENTS

Abstract Background and Aims Calcineurin inhibitors, cyclosporine and tacrolimus have a narrow therapeutic index and have wide intra- and inter individual pharmacokinetic variability. They are metabolized mainly by CYP3A4 and CYP3A5. The P450 oxidoreductase POR*28 variant allele has been associated with changes in cytochrome P450 enzymatic activity that can affect the therapeutic level of both medications. The aim of this study is to investigate the allelic frequency of the POR*28 in Egyptian renal transplant patients and to evaluate the effect of the presence of CYP3A5*1, CYP3A4*22, and POR*28 genetic polymorphism on calcineurins inhibitos dose requirements and adjustments. Method A prospective clinical trial that included 130 renal transplant patients placed on either tacrolimus or cyclosporine. Patients were genotyped for POR*28, CYP3A4*22, and CYP3A5*1. The relation between the present genetic polymorphisms and tacrolimus and cyclosporine doses and dose adjustments were studied at days 14, 30, and 90 post-transplantation. Results The POR*28 allele frequency in the studied population was 29.61%. The tacrolimus dose-adjusted trough concentration ratio (C0/D) was highly statistically significant in the fast metabolizers group (CYP3A5*1/POR*28T carriers) than in the slow metabolizers group (CYP3A5*3/*3/CYP3A4*22 carriers) throughout the study (14, 30, and 90 days) (p value 0.001, &amp;lt;0.001, and 0.003, respectively). There was no significant effect for this gene combination on cyclosporine (C0/D). Conclusion Combining the CYP3A5*1, POR*28, and CYP3A4*22 genotypes can be of significant value in early tacrolimus dose requirements and adjustments. However, it does not have any influence on cyclosporine dose requirements.

CYP3A4/5 genotypes and age codetermine tacrolimus concentration and dosage in pediatric heart transplant recipients

Tacrolimus (TAC) is the cornerstone of immunosuppressive therapy for pediatric heart transplantation (HTx) recipients. However, little information is known on the interaction of developmental and genetic variants on TAC disposition in this population, which makes TAC dose optimization more difficult. The aim of study was to investigate the relationship between genotypes and age on TAC concentrations and dosage during the early post-operation period in pediatric HTx recipients. Sixty-six pediatric HTx recipients were enrolled and divided into three groups according to the age (<6, ≥6-≤12, 12–18 years old). CYP3A4/5, POR and ABCB1 polymorphisms were genotyped. The associations between genotypes and age on TAC dose-adjusted trough concentrations (C0/D), dose requirement as well as acute kidney injury (AKI) were evaluated. CYP3A5*3 and CYP3A4*1G were significantly correlated with TAC C0/D and dose requirement in the pediatric recipients ≥ 6 years. The C0/D in children aged ≥ 6-≤12 years and 12–18 years is 2.8 and 4.2 fold of these < 6 years old, respectively. TAC dose requirements in children aged < 6 years were 2.4 times and 3.5 times of these aged ≥ 6-≤12 years and 12–18 years, respectively. Among the same CYP3A5*3 or CYP3A4*1G genotypes, age was positively increased with TAC C0/D and negatively correlated with targeted dose. No genetic variants were found to be associated with AKI during the early post-operation period. CYP3A4/5 genotypes and age should be taken into consideration to TAC dosage in pediatric HTx recipients.

The Pharmacogenetics of Tacrolimus in Corticosteroid-Sparse Pediatric and Adult Kidney Transplant Recipients.

IntroductionTacrolimus is a calcineurin inhibitor used as an immunosuppressant drug in solid organ transplantation, and is mainly metabolized by cytochrome P450 (CYP) 3A4 and CYP3A5. Studies have shown an association between the CYP3A5 genotype and tacrolimus dose-adjusted trough concentrations. Variants in the genes PPARA, POR and CYP3A4 have recently been shown to influence tacrolimus metabolism. Furthermore, pharmacokinetic interaction between corticosteroid treatment and tacrolimus has been shown. In the present study, we investigated a potential association between CYP3A5*3, PPARA c.209-1003G>A, POR*28 and CYP3A4*22 and dose-adjusted tacrolimus trough concentrations in a primarily corticosteroid-free (>85%) population of Danish pediatric and adult kidney transplant recipients.MethodsSeventy-two patients receiving treatment with oral tacrolimus were genotyped using real-time polymerase chain reaction and Primer-Probe Detection. Tacrolimus trough concentrations, corresponding doses and covariates were retrospectively collected from the patients’ medical charts.ResultsIt was confirmed that CYP3A5*1 wild-type carriers had lower median dose-adjusted tacrolimus trough concentrations compared with noncarriers. Adults had 56 and 77% lower trough concentrations at 6 weeks (p = 0.0003) and 1 year, respectively (p < 0.0017), and, similarly, children had 65 and 39% lower median concentrations, with p values of 0.006 and 0.011, respectively. No association was found for PPARA c.209-1003G>A, POR*28, or CYP3A4*22. An association between the PPARA c.209-1003G>A genotype and an increased number of infections with cytomegalovirus (CMV) within the first year was identified (p < 0.05). Only 29% of trough concentrations measured between 2 and 12 weeks post-transplantation were on target.ConclusionThis study shows that the known association of the CYP3A5 genotype with tacrolimus dose-adjusted trough concentrations has the same impact in a corticosteroid-sparse population. The association between PPARA variance and infections with CMV will need further investigation.Electronic supplementary materialThe online version of this article (doi:10.1007/s40268-017-0177-9) contains supplementary material, which is available to authorized users.

The genetic polymorphisms of POR*28 and CYP3A5*3 significantly influence the pharmacokinetics of tacrolimus in Chinese renal transplant recipients.

The aims of this study were to assess the influence of the polymorphism of cytochrome P450 oxidoreductase (POR) as well as other relevant genes (CYP3A4, CYP3A5, ABCB1) on individual variability of tacrolimus pharmacokinetics and perform population pharmacokinetic analysis of tacrolimus in Chinese renal transplant recipients. Tacrolimus trough whole blood concentrations and clinical details were retrospectively collected from 83 renal recipients. CYP3A4*1G, CYP3A5*3, and ABCB1 C3435T were genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), POR*28 and CYP3A4*22 were genotyped by sequencing method. Population pharmacokinetic analysis was performed using NONMEM program. The significant influences of CYP3A5*3, CYP3A4*1G, and POR*28 polymorphisms on tacrolimus dose-adjusted trough concentrations (C0/D) were observed in 83 renal recipients. Subgroup analysis showed that POR*28 polymorphisms significantly decreased tacrolimus C0/D by 1.50 - 1.84-fold (p < 0.05) in patients who were CYP3A5 expressers (CYP3A5*1 carriers, n = 46), while similar results could not be obtained from CYP3A5 non-expressers (CYP3A5*3/*3 carriers, n = 37). Additionally, population pharmacokinetic analysis identified that the combined genotype of CYP3A5-POR was the only covariant for the apparent clearance of tacrolimus (CL/F). The study demonstrated that the POR*28 C>T mutation could decrease the C0/D of tacrolimus in renal recipients who were CYP3A5 expressers. The population pharmacokinetic model showed that the combined genotype of CYP3A5-POR was associated with the CL/F of tacrolimus which might provide references for personalized use of tacrolimus in clinic.

Potential role of tacrolimus in erythrocytes’ antioxidative capacity in long-term period after renal transplantation

The main goal of this study was to evaluate the influence of tacrolimus daily dose (TDD) as well as cytochrome P450 (CYP) 3A5 6986A>G and ABCB1 3435C>T polymorphisms on the erythrocytes’ oxidative stress parameters in long-term period after renal transplantation (Tx). Secondly, we investigated whether tacrolimus and/or oxidative injury might have affected renal function or it was independent from both. In order to evaluate erythrocytes’ oxidative stress status in 72 renal transplant recipients and 62 healthy volunteers, we measured the levels of thiobarbituric acid reactive substances (TBARS) and reduced glutathione (GSH) and the activities of superoxide dismutase (SOD), glutathione peroxidase (GPX) and glutathione reductase (GR) as well. Also, we performed allele-specific PCR to determine CYP 3A5 and ABCB1 polymorphisms. Erythrocytes’ TBARS positively correlated with SOD, GPX and negatively with GFR. Tested polymorphisms affected TDD, but not oxidative stress parameters. TDD positively correlated with GSH and negatively with GFR. Additionally, tacrolimus dose-adjusted trough concentrations positively correlated with GFR and negatively with GPX and GSH. Furthermore, regression analysis showed that TBARS and TDD independently and negatively affected GFR in long term period after Tx. Our findings suggest that tacrolimus may increase erythrocytes’ antioxidative capacity. Regardless, it may be involved in renal function decline in a long-term period after Tx, which seems to be independent from oxidative stress mediated reduction in renal function.

Impact of PPARA and POR polymorphisms on tacrolimus pharmacokinetics and new-onset diabetes in kidney transplant recipients.

Recent efforts have been made to identify genetic markers of CYP3A4 enzymatic activity within genes encoding for regulatory elements. The aim of the current study was to investigate the impact of polymorphism of PPARA and POR genes on tacrolimus (TAC) dose-adjusted trough concentration and risk of new-onset diabetes after transplantation (NODAT). A total of 241 White kidney transplant patients were genotyped for three functional single nucleotide polymorphisms: rs1057868 (*28) in POR, rs4253728:G>A, and rs4823613:A>G in PPARA. No significant genotype-dependent differences in TAC dose-adjusted trough concentration were observed for either POR or PPARA variants. No significant differences in the incidence of NODAT were observed between patients stratified by PPARA and POR genotypes. The frequency of NODAT among PPARA rs4253728 AA homozygotes (42%) was higher compared with heterozygotes (22%) and GG homozygotes (19%), but the difference was not significant. Testing TAC-medicated renal transplant recipients for POR and PPARA variants seems to have limited clinical application.

Influence of TLR4 rs1927907 locus polymorphisms on tacrolimus pharmacokinetics in the early stage after liver transplantation

The aim of this study was to assess the potential influence of single nucleotide polymorphisms (SNPs) in the TLR4 gene on tacrolimus pharmacokinetics in the early stage after liver transplantation. A total of 96 liver transplant patients receiving tacrolimus-based immunosuppressive regimens were enrolled in this study. The SNPs of CYP3A5 rs776746 and TLR4 rs1927907 were genotyped in both donors and recipients. Trough tacrolimus concentration (ng/mL) and tacrolimus daily doses (mg/day) were recorded for the first 4 weeks post-transplantation. The tacrolimus dose-adjusted trough concentrations (C/D ratio) required to achieve target concentrations were compared among patients according to allele status for CYP3A5 rs776746 and TLR4 rs1927907 during the first 4 weeks post-transplantation. Both donor and recipient CYP3A5 rs776746 allele A and donor TLR4 rs1927907 allele A were associated with a lower C/D ratio during the early stage after transplantation. The difference was even more striking in patients with both the CYP3A5 and TLR4 genotypes. With increasing numbers of genotype AA/AG, patients were found to have increasingly lower tacrolimus C/D ratios at all time points between post-transplantation weeks 1 and 4. Collectively, donor TLR4 rs1927907 SNPs were closely associated with tacrolimus elimination in our Chinese Han patient population. The combination of the donor TLR4 rs1927907 SNP and both donor and recipient CYP3A5 rs776746 SNP might have a greater effect on tacrolimus elimination than each SNP separately. Screening for these SNPs prior to liver transplantation might be useful for determining adequate initial daily doses of immunosuppressive agents and achieving the desired immunosuppressive effect.

Association of Hemoglobin Levels, CYP3A5, and NR1I3 Gene Polymorphisms with Tacrolimus Pharmacokinetics in Liver Transplant Patients

Tacrolimus is a widely used immunosuppressant after organ transplantation. The narrow therapeutic window and individual variability in tacrolimus pharmacokinetics make management of this agent a great challenge. This study was undertaken to determine the association of clinical markers, cytochrome P450, family 3, subfamily A, polypeptide 5 (CYP3A5) and nuclear receptor subfamily 1, group I, member 3 (NR1I3) gene polymorphisms with tacrolimus pharmacokinetics. A total of 96 liver transplant patients were enrolled in the study. Tacrolimus dose-adjusted trough concentration (C/D ratio) and clinical markers were recorded for one month after transplantation. CYP3A5 and NR1I3 gene polymorphisms for both donor and recipient were genotyped. In single variable analysis, hemoglobin (Hb), hematocrit (Hct), donor CYP3A5, NR1I3 gene polymorphisms and recipient CYP3A5 gene polymorphisms were associated with log-transformed tacrolimus C/D ratios. Hb, donor CYP3A5, NR1I3 gene polymorphisms and recipient CYP3A5 gene polymorphisms showed association with log-transformed tacrolimus C/D ratios in the final multiple linear regression model. Donor CYP3A5 polymorphisms were the most important variant, accounting for 14.3% of total variation involved in tacrolimus pharmacokinetics. This information could be useful in developing individualized tacrolimus treatment after liver transplantation.

CYP3A4/5 polymorphisms affect the blood level of cyclosporine and tacrolimus in Chinese renal transplant recipients

Both cyclosporine and tacrolimus display a narrow therapeutic index as well as high interindividual pharmacokinetic variability. We approached the effect of the CYP3A4*18B and CYP3A5*3 polymorphisms and haplotypes on the whole blood cyclosporine or tacrolimus concentration in Chinese renal transplant patients during the first month after transplantation. A total of 83 recipients receiving tacrolimus or cyclosporine was genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The whole blood concentration was measured by enzyme-multiplied immunoassay technique. Both CYP3A4*18B and CYP3A5*3 polymorphisms affected the tacrolimus dose-adjusted trough concentration (C0/D). The tacrolimus C0/D was higher in carriers of haplotype GG compared with the non-carriers. The cyclosporine dose-adjusted 2-hour post-dose concentrations (C2/D), dose-adjusted C0 + C2 ((C0 + C2)/D) and C2/C0 during Days 15 - 21 displayed significant difference among the three genotypes. Statistical difference was observed between CYP3A4*1/*1 and CYP3A4*18B/*18B groups and between CYP3A4*1/*18B and CYP3A4*18B/*18B groups, but no difference was detected between CYP3A4*1/*1 and CYP3A4*1/*18B groups. No difference was found in C0/D among the three genotypes of CYP3A4*18B polymorphism, and neither CYP3A5*3 polymorphisms nor CYP3A haplotype-derived genotypes affected the cyclosporine dose-adjusted concentration. Genetic polymorphisms of CYP3A5*3 and CYP3A4*18B may be partly responsible in large interindividual variability of cyclosporine and tacrolimus blood levels in Chinese renal transplant patients during the first month after transplantation. A patient carried combined genotype of CYP3A4*1/*1-CYP3A5* 3/*3 might require lower tacrolimus doses to achieve target concentration levels. Genotyping of CYP3A4*18B and CYP3A5*3 before transplantation is of benefit in determining a suitable initial dose for each patient.

Impact of Cytochrome P450 3A and ATP-Binding Cassette Subfamily B Member 1 Polymorphisms on Tacrolimus Dose-Adjusted Trough Concentrations Among Korean Renal Transplant Recipients

BackgroundTacrolimus is a substrate of cytochrome P450 3A (CYP3A) and P-glycoprotein (P-gp), encoded by the CYP3A and ATP-binding cassette subfamily B member 1 (ABCB1) genes, respectively. This study was aimed to investigate the impact of CYP3A and ABCB1 polymorphisms on the tacrolimus pharmacokinetics and clinical outcomes in Korean renal transplant recipients. MethodsWe analyzed data from a cohort of 70 renal transplant recipients receiving tacrolimus. CYP3A4*4, CYP3A4*5, CYP3A4*18, CYP3A5*3, ABCB1 C1236>T, ABCB1 G2677>T/A, and ABCB1 C3435>T polymorphisms were genotyped and correlated to dose-adjusted tacrolimus trough concentration at months 1, 3, 6, and 12 after transplantation. ResultsPatients with the CYP3A5*3 alleles showed higher dose-adjusted tacrolimus concentrations for 12 months and higher trough levels until 6 months after transplantation. ABCB1 polymorphisms and haplotypes were not associated with tacrolimus concentrations. In a multivariate analysis, the presence of ≥1 CYP3A5*3 allele was a significant independent variable affecting dose-adjusted tacrolimus concentrations. Glomerular filtration rate, acute rejection, opportunistic infection, and graft survival were not affected by CYP3A5 polymorphisms. Calcineurin inhibitor toxicity, which showed higher tendency in patients with CYP3A5*1 alleles, might be associated with higher tacrolimus dose per kilogram. ConclusionsThe CYP3A5 genotype is a major factor in determining the dose requirement of tacrolimus, and genotyping may be of value in individualization of immunosuppressive therapy of renal transplant patients.

Pharmacogenetics of Calcineurin Inhibitors in Brazilian Renal Transplant Patients

Polymorphisms in the CYP3A5 and ABCB1 genes have been investigated as modulators of the pharmacokinetics and clinical effects of cyclosporine (CSA) and tacrolimus (TAC) in European, North American and Asian populations, with controversial results. The extensive variation in worldwide frequency distribution of CYP3A5 and ABCB1 polymorphisms is a caveat against the extrapolation of these data to the heterogeneous and admixed Brazilian population. We investigated the effect of CYP3A5 and ABCB1 polymorphisms on CSA and TAC dose-adjusted trough concentration (C₀/dose) in Brazilian renal transplant recipients, during the first 3 months post-transplantation. Patients receiving CSA (n = 150) or TAC (n = 151) were genotyped for CYP3A5*3 (rs776746, 6986A>G), *6 (rs10264272, 14690G>A) and *7 (rs41303343, 27131-27132insT) and for ABCB1 1236C>T (rs1128503), 2677G>T/A (rs2032582) and 3435C>T (rs1045642) polymorphisms. We explored the effects of CYP3A5 and ABCB1 polymorphisms, clinical and demographical characteristics on CSA and TAC C₀/dose under a two-step data analysis strategy by fitting a longitudinal mixed-effects model to the data; first to select the important covariates under a univariate setting and then to fit the final multivariate model. C₀/dose of TAC was associated with the number of CYP3A5-defective alleles, in a gene-dose manner, throughout the observation period, whereas C₀/dose of CSA was associated with body surface area and prednisone dosing. No other significant associations were detected. Individual adjustment of the initial TAC dose according to the CYP3A5 haplotypes comprising the CYP3A5*3, *6 and *7 defective alleles might prove beneficial to Brazilian renal transplant recipients and should be further investigated in prospective trials.

Effect of CYP3A and ABCB1 Single Nucleotide Polymorphisms on the Pharmacokinetics and Pharmacodynamics of Calcineurin Inhibitors: Part I

The calcineurin inhibitors ciclosporin (cyclosporine) and tacrolimus are immunosuppressant drugs used for the prevention of organ rejection following transplantation. Both agents are metabolic substrates for cytochrome P450 (CYP) 3A enzymes--in particular, CYP3A4 and CYP3A5--and are transported out of cells via P-glycoprotein (ABCB1). Several single nucleotide polymorphisms (SNPs) have been identified in the genes encoding for CYP3A4, CYP3A5 and P-glycoprotein, including CYP3A4 -392A>G (rs2740574), CYP3A5 6986A>G (rs776746), ABCB1 3435C>T (rs1045642), ABCB1 1236C>T (rs1128503) and ABCB1 2677G>T/A (rs2032582). The aim of this review is to provide the clinician with an extensive overview of the recent literature on the known effects of these SNPs on the pharmacokinetics of ciclosporin and tacrolimus in solid-organ transplant recipients. Literature searches were performed, and all relevant primary research articles were critiqued and summarized. Influence of the CYP3A4 -392A>G SNP on the pharmacokinetics of either ciclosporin or tacrolimus appears limited. Variability in CYP3A4 expression due to environmental factors is likely to be more important than patient genotype. Influence of the CYP3A5 6986A>G SNP on the pharmacokinetics of ciclosporin is also uncertain and likely to be small. CYP3A4 may play a more dominant role than CYP3A5 in the metabolism of ciclosporin. The CYP3A5 6986A>G SNP has a well established influence on the pharmacokinetics of tacrolimus. Several studies in kidney, heart and liver transplant recipients have reported an approximate halving of tacrolimus dose-adjusted trough concentrations and doubling of tacrolimus dose requirements in heterozygous or homozygous carriers of a CYP3A5*1 wild-type allele compared with homozygous carriers of a CYP3A5*3 variant allele. Carriers of a CYP3A5*1 allele take a longer time to reach target blood tacrolimus concentrations. Influence of ABCB1 3435C>T, 1236C>T and 2677G>T/A SNPs on the pharmacokinetics of ciclosporin and tacrolimus remains uncertain, with inconsistent results. Genetic linkage between the three variant genotypes suggests that the pharmacokinetic effects are complex and not related to any one ABCB1 SNP. It is likely that these polymorphisms exert a small but combined effect, which is additive to the effects of the CYP3A5 6986A>G SNP. In liver transplant patients, recipient and donor liver genotypes may act together in determining overall drug disposition, hence the importance of assessing both. Studies with low patient numbers may account for many inconsistent results to date. Meta-analyses of the current data should help resolve some discrepancies. The majority of studies have only evaluated the effects of individual SNPs; however, multiple polymorphisms may interact to produce a combined effect. Further haplotype analyses are likely to be useful. It is not yet clear whether pharmacogenetic profiling of calcineurin inhibitors will be a useful clinical tool for personalizing immunosuppressant therapy.