Tacrolimus Trough Concentrations Research Articles

Exploring the Knowledge, Attitude, and Practice of Sudanese Medical Doctors Towards Tacrolimus, at Ahmed Gasim Hospital, Kidney Transplant Center Unit, Khartoum, Sudan (2022 – 2023)

Tacrolimus is one of the most commonly prescribed immunosuppressive drugs that varies between individuals depending on different ethnic groups, the presence of different CYP3A5 genetic variants, and the duration of time since the transplantation, which makes targeting optimal tacrolimus concentration levels more challenging. This study aimed to explore the knowledge, attitude, and practice of Sudanese medical doctors towards Tacrolimus. An observational, cross-sectional study was conducted on the Sudanese medical doctors in the nephrology clinic at Ahmed Gasim Hospital, Kidney Transplant Center Unit, Khartoum, Sudan, who were in direct contact with kidney transplant patients under tacrolimus treatment. Data were collected using a questionnaire modified to record the pharmacogenomic impact. The data were analyzed using a statistical package for social sciences (SPSS). Total of 15 medical doctors, Female 8 (53.3%) and male 7 (46.7%) with mean ± SD age of 31.60 ± (3.906). All of them were currently practicing in governmental hospitals (n=15; 83.3%), private hospitals (n=2; 11.1%), and private clinics (n=1; 6.7%). There were 67% of the medical doctors had high knowledge about the genetic profile of the patient's impact on the tacrolimus trough concentrations, while 66.7% of the medical doctors had low attitude levels toward tacrolimus. The observations among the different Sudanese ethnic groups tacrolimus trough concentrations were found to be variable, as Arabs and Fulani were observed to have low trough concentrations (n=6; 40%), while Nuba and Beja were observed to have high trough concentrations (n=5; 33.3%), instead of fur observed to had fluctuations (n=2; 13.3%). A significant correlation between practice toward tacrolimus with the location of practice, doctor specialty, and years of experience was found (P value ≤ 0.05). The medical doctors exerted a high level of knowledge about the impact of the genetic profile (metabolic alleles) in the dosing and dose adjustment of tacrolimus.

Tacrolimus Monitoring in Liver Transplant Recipients, Posttransplant Cholestasis: A Comparative Between 2 Commercial Immunoassays and a Liquid Chromatography-Tandem Mass Spectrometry Method.

Cholestasis commonly occurs after orthotopic liver transplantation. It can be extrahepatic because of mechanical obstruction or intrahepatic because of various causes. During cholestasis episodes, blood concentrations of tacrolimus (TAC) metabolites may increase, potentially affecting TAC concentrations measured by immunoassays. This study aimed to simultaneously evaluate the analytical performance of 2 TAC immunoassays, a quantitative microsphere system (QMS) immunoassay, and chemiluminescence microparticle immunoassay, using liquid chromatography-tandem mass spectrometry (LC-MS/MS) as a reference method in liver transplant recipients. This single-center study included 265 patients who underwent orthotopic liver transplantation. In total, 942 blood samples were collected. TAC trough concentrations were measured using LC-MS/MS and 2 immunoassays in parallel. The plasma concentrations of conjugated bilirubin were measured in all samples. The results were analyzed using Bland-Altman plots and Passing-Bablok regressions. The Bland-Altman plot analysis showed that the TAC QMS immunoassay has a significant bias (+37%) compared with LC-MS/MS, and this bias was higher in patients with cholestasis with hyperbilirubinemia (≤+70% in patients with conjugated bilirubin >150 µmol/L). In comparison, the chemiluminescence microparticle immunoassay showed acceptable analytical performance in patients with hyperbilirubinemia (bias <10%). In agreement with previous findings, the TAC QMS immunoassay showed a positive bias compared with LC-MS/MS. This bias is remarkably high in patients with cholestasis and hyperbilirubinemia, suggesting the cross-reactivity of TAC metabolites with the monoclonal antibody used in the QMS immunoassay.

Adaptative Strategy of Immunosuppressive Drugs Dosage Adjustments When Combined With Nirmatrelvir/Ritonavir in Solid Organ Transplant Recipients With COVID-19.

Nirmatrelvir/ritonavir is a promising option for preventing severe COVID-19 in solid organ transplant recipients with SARS-CoV-2 infection. However, concerns have arisen regarding potential drug interactions with calcineurin inhibitors (CNI). This two-phase multicentre retrospective study, involving 113 patients on tacrolimus and 13 on cyclosporine A, aimed to assess the feasibility and outcomes of recommendations issued by The French societies of transplantation (SFT) and pharmacology (SFPT) for CNI management in this context. The study first evaluated adherence to recommendations, CNI exposure, and clinical outcomes. Notably, 96.5% of patients on tacrolimus adhered to the recommendations, maintaining stable tacrolimus trough concentrations (C0) during nirmatrelvir/ritonavir treatment. After reintroduction, most patients experienced increased C0, with 42.9% surpassing 15ng/mL, including three patients exceeding 40ng/mL. Similar trends were observed in cyclosporine A patients, with no COVID-19-related hospitalizations. Moreover, data from 22 patients were used to refine the reintroduction strategy. Modelling analyses suggested reintroducing tacrolimus at 50% of the initial dose on day 8, and then at 100% from day 9 as the optimal approach. In conclusion, the current strategy effectively maintains consistent tacrolimus exposure during nirmatrelvir/ritonavir treatment, and a stepwise reintroduction of tacrolimus may be better suited to the low CYP3A recovery.

High intra-patient variability of tacrolimus within post-operative 1month predicted worse 1-year outcomes in pediatric liver transplant recipients.

The pharmacokinetics of tacrolimus (TAC) show high intra-patient variability (IPV), which is associated with poor long-term outcomes following adult liver transplantation(LT). However, this relationship remains to be confirmed in pediatric liver transplant (PLT) recipients. The present study aimed to investigate the association between TAC IPV and grafts or patient outcomes after pediatric liver transplantion. This retrospective study included 848 PLT recipients (including infants) between January, 2016, and June, 2021. The IPV of TAC concentrations was estimated by calculating the coefficient of variation (CV) of trough concentrations in whole blood within 1month after transplantation. Patients were categorized into two groups, low IPV (CV < 45%) and high IPV (CV ≥ 45%), based on the third quartile of the CV distribution. A total of 848 patients were included in our study. The low CV group included 614 patients, with a mean TAC trough concentration of 8.59 ± 1.65ng/ml and a median CV of 32.37%. In contrast, the high CV group included 214 patients, the mean TAC trough concentration and median CV were 8.81 ± 2.00ng/ml and 54.88%, respectively. The median hospital duration was significantly higher in the high CV group (22days vs. 20days, P = 0.01). Univariate analysis was performed to evaluate the significant differences in 1-year recipient survival (P = 0.041) and 1-year graft survival (P = 0.005) between the high- and low-CV groups. Moreover, high CV (HR 2.316, 95%CI 1.026-5.231, P = 0.043) and persistent EBV viremia (HR 13.165, 95%CI 3.090-56.081, P < 0.001) were identified as independent risk factors for 1- year mortality after PLT. PLT recipients with high TAC trough concentration of CV in the first month were associated with poor 1-year outcomes. This CV calculation provides a valuable strategy to monitor TAC exposure.

Does Antibiotic Use Increase the Risk of Post-Transplantation Diabetes Mellitus? A Retrospective Study of Renal Transplant Patients.

BACKGROUND This study aimed to investigate the incidence of post-transplant diabetes mellitus (PTDM) in renal transplant (RT) patients at our center and to explore new risk factors for PTDM. MATERIAL AND METHODS This retrospective study included RT patients from 2010 to 2022. Clinic data on RT patients were obtained from hospital electronic medical records. CYP3A5*3, POR*28, ABCB1 (3435 C>T), and ABCB1 (1236 C>T) were genotyped in RT patients. The associations between age, BMI, concentration of tacrolimus (TAC), polymorphism of genes, antibiotics (eg, penicillins, cephalosporins, oxazolidinones, quinolones), numbers and days of antibiotic use, and PTDM were analyzed. RESULTS In this study, 409 patients with RT were included. The cumulative incidence of PTDM in the first year after RT was 9.05%. The numbers and days of antibiotic use in PTDM patients were significantly higher than those in non-PTDM patients. Multivariate logistic regression analysis identified age (OR=1.047, P=0.014), body mass index (BMI) (OR=1.178, P=0.007), dose-adjusted trough concentration of TAC (TAC C₀/D) at 7 days after RT (OR=1.159, P=0.042), trough concentration of TAC (TAC C₀) at 28 days after RT (OR=1.094, P=0.042), and levofloxacin (OR=5.975, P=0.003) as independent risk factors for PTDM. CONCLUSIONS In addition to age, BMI, and TAC concentration after RT, antibiotic use may be a novel factor affecting PTDM. The use of antibiotics may influence the development of PTDM.

Relevance of Tacrolimus Trough Concentration and Hepatitis E virus Genetic Changes in Kidney Transplant Recipients With Chronic Hepatitis E

IntroductionHepatitis E virus (HEV) can cause chronic infection (≥3 months) and cirrhosis in immunocompromised patients, especially kidney transplant recipients. Low ALT levels and high HEV intra-host diversity have previously been associated with evolution toward chronicity in these patients. We hypothesized that additional clinical and viral factors could be associated with the risk of chronic HEV infection. MethodsWe investigated a series of 27 kidney transplant recipients with HEV infection, including 20 patients with chronic hepatitis E. ResultsHigh tacrolimus trough concentration at diagnosis was the most relevant marker associated with chronic hepatitis E (9.2 vs 6.4 ng/mL, p = 0.04). Most HEV genetic changes selected during HEV infection were compartmentalized between plasma and feces. DiscussionThis compartmentalization highlights the diversity and complexity of HEV replication compartments. Tacrolimus trough concentration at diagnosis of HEV infection could allow an early identification of patients at high risk of chronic hepatitis E and guide treatment initiation.

Pharmacogenomic Analysis of CYP3A5*3 and Tacrolimus Trough Concentrations in Vietnamese Renal Transplant Outcomes.

CYP3A5 polymorphisms have been associated with variations in the pharmacokinetics of tacrolimus (Tac) in kidney transplant patients. Our study aims to quantify how the CYP3A5 genotype influences tacrolimus trough concentrations (C0) in a Vietnamese outpatient population by selecting an appropriate population pharmacokinetic model of Tac for our patients. The external dataset was obtained prospectively from 54 data of adult kidney transplant recipients treated at the 103 Military Hospital. All published Tac population pharmacokinetic models were systematically screened from PubMed and Scopus databases and were selected based on our patient's available characteristics. Mean absolute prediction error (MAPE), mean prediction error, and goodness-of-fit plots were used to identify the appropriate model for finding the formula that identifies the influence of CYP3A5 genotype on the pharmacokinetic data of Vietnamese patients. The model of Zhu et al had a good predictive ability with MAPE of 19.29%. The influence of CYP3A5 genotype on tacrolimus clearance was expressed by the following formulas: . The simulation result showed that Tac C0 was significantly higher in patients not expressing CYP3A5 (p< 0.001). The incorporation of the CYP3A5 phenotype into Zhu's structural model has significantly enhanced our ability to predict Tacrolimus trough levels in the Vietnamese population. This study's results underscore the valuable role of CYP3A5 phenotype in optimizing the forecast of Tac concentrations, offering a promising avenue to assist health-care practitioners in their clinical decision-making and ultimately advance patient care outcomes.

Pharmacokinetics of Tacrolimus in Pregnant Solid-Organ Transplant Recipients: A Retrospective Study.

Data on the pharmacokinetics of tacrolimus during pregnancy are limited. Therefore, the aim of this retrospective study was to characterize the whole-blood pharmacokinetics of tacrolimus throughout pregnancy. In this single-center retrospective cohort study, whole-blood tacrolimus trough concentrations corrected for the dose (concentration-to-dose [C/D] ratios) were compared before, monthly during, and after pregnancy in kidney, liver, and lung transplant recipients who became pregnant and gave birth between 2000 and 2022. Descriptive statistics and linear mixed models were used to characterize changes in tacrolimus C/D ratios before, during, and after pregnancy. The total study population included 46 pregnancies (31 pregnant women). Nineteen, 21, and 6 pregnancies were following kidney, liver, and lung transplantation, respectively. Immediate-release or extended-release formulations were used in 54.5% and 45.5% of the women, respectively. Tacrolimus C/D ratios significantly (P<.001) decreased (-48%) compared to the prepregnancy state at 7 months of pregnancy. These ratios recovered within 3 months postpartum (P = .002). C/D ratios tended to be lower during treatment with an extended-release formulation than with an immediate-release formulation (P = .071). Transplantation type did not significantly affect C/D ratios during pregnancy (P = .873). In conclusion, we found that tacrolimus whole-blood pharmacokinetics change throughout pregnancy, with the lowest C/D ratios (48% decrease) in the 7th month of pregnancy. In general, the decrease in C/D ratios seems to stabilize from month 4 onward compared to prepregnancy.

Impact of Switching From Immediate- or Prolonged-Release to Once-Daily Extended-Release Tacrolimus (LCPT) on Tremor in Stable Kidney Transplant Recipients: The Observational ELIT Study.

Once-daily extended-release tacrolimus (LCPT) exhibits increased bioavailability versus immediate-release (IR-TAC) and prolonged release (PR-TAC) tacrolimus. Improvements in tremor were previously reported in a limited number of kidney transplant patients who switched to LCPT. We conducted a non-interventional, non-randomized, uncontrolled, longitudinal, prospective, multicenter study to assess the impact of switching to LCPT on tremor and quality of life (QoL) in a larger population of stable kidney transplant patients. The primary endpoint was change in The Essential Tremor Rating Assessment Scale (TETRAS) score; secondary endpoints included 12-item Short Form Survey (SF-12) scores, tacrolimus trough concentrations, neurologic symptoms, and safety assessments. Subgroup analyses were conducted to assess change in TETRAS score and tacrolimus trough concentration/dose (C0/D) ratio by prior tacrolimus formulation and tacrolimus metabolizer status. Among 221 patients, the mean decrease of TETRAS score after switch to LCPT was statistically significant (p < 0.0001 vs. baseline). There was no statistically significant difference in change in TETRAS score after switch to LCPT between patients who had received IR-TAC and those who had received PR-TAC before switch, or between fast and slow metabolizers of tacrolimus. The overall increase of C0/D ratio post-switch to LCPT was statistically significant (p < 0.0001) and from baseline to either M1 or M3 (both p < 0.0001) in the mITT population and in all subgroups. In the fast metabolizers group, the C0/D ratio crossed over the threshold of 1.05ng/mL/mg after the switch to LCPT. Other neurologic symptoms tended to improve, and the SF-12 mental component summary score improved significantly. No new safety concerns were evident. In this observational study, all patients had a significant improvement of tremor, QoL and C0/D ratio post-switch to LCPT irrespective of the previous tacrolimus formulation administered (IR-TAC or PR-TAC) and irrespective from their metabolism status (fast or slow metabolizers).

Association between the early high level of serum tacrolimus and recurrence of hepatocellular carcinoma in ABO-incompatible liver transplantation.

Clinical factors predicting graft survival (GS) after ABO-incompatible (ABOi) liver transplantation (LT), and differences between recipients with and without hepatocellular carcinoma (HCC) are unclear. To analyze the impact of serial serum tacrolimus trough concentration in recipients with or without HCC) in ABOi living-donor liver transplantation (LDLT). We analyzed a historical cohort of 89 recipients who underwent ABOi LDLT, including 47 patients with HCC. The 1-, 3-, 5-, and 10-year GS rates were 85.9%, 73.3%, 71.4%, and 71.4%, respectively, and there were no significant differences between HCC and non-HCC recipients. In multivariate Cox-regression analyses, tacrolimus trough concentrations below 5.4 ng/mL at 24 wk post-LT, in addition to the antibody-mediated rejection (AMR) were associated with poor-graft outcomes. In HCC patients, AMR [hazard ratio (HR) = 63.20, P < 0.01] and HCC recurrence (HR = 20.72, P = 0.01) were significantly associated with poor graft outcomes. HCCs outside Milan criteria, and tacrolimus concentrations at 4 wk post-LT > 7.3 ng/mL were significant predictive factors for HCC recurrence. After propensity score matching, patients with high tacrolimus concentrations at 4 wk had significantly poor recurrence-free survival. Elevated tacrolimus levels at 4 wk after ABOi LDLT have been found to correlate with HCC recurrence. Therefore, careful monitoring and control of tacrolimus levels are imperative in ABOi LT recipients with HCC.

Dosing strategies for de novo once-daily extended release tacrolimus in kidney transplant recipients based on CYP3A5 genotype.

Tacrolimus extended-release tablets have been Food and Drug Administration-approved for use in the de novo kidney transplant population. Dosing requi rements often vary for tacrolimus based on several factors including variation in metabolism based on CYP3A5 expression. Patients who express CYP3A5 often require higher dosing of immediate-release tacrolimus, but this has not been established for tacrolimus extended-release tablets in the de novo setting. To obtain target trough concentrations of extended-release tacrolimus in de novo kidney transplant recipients according to CYP3A5 genotype. Single-arm, prospective, single-center, open-label, observational study (ClinicalTrials.gov: NCT037 13645). Life cycle pharma tacrolimus (LCPT) orally once daily at a starting dose of 0.13 mg/kg/day based on actual body weight. If weight is more than 120% of ideal body weight, an adjusted body weight was used. LCPT dose was adjusted to maintain tacrolimus trough concentrations of 8-10 ng/mL. Pharmacogenetic analysis of CYP3A5 genotype was performed at study conclusion. Mean time to therapeutic tacrolimus trough concentration was longer in CYP3A5 intermediate and extensive metabolizers vs CYP3A5 non-expressers (6 d vs 13.5 d vs 4.5 d; P = 0.025). Mean tacrolimus doses and weight-based doses to achieve therapeutic concentration were higher in CYP3A5 intermediate and extensive metabolizers vs CYP3A5 non-expressers (16 mg vs 16 mg vs 12 mg; P = 0.010) (0.20 mg/kg vs 0.19 mg/kg vs 0.13 mg/kg; P = 0.018). CYP3A5 extensive metabolizers experienced lower mean tacrolimus trough concentrations throughout the study period compared to CYP3A5 intermediate metabolizers and non-expressers (7.98 ng/mL vs 9.18 ng/mL vs 10.78 ng/mL; P = 0 0.008). No differences were identified with regards to kidney graft function at 30-d post-transplant. Serious adverse events were reported for 13 (36%) patients. Expression of CYP3A5 leads to higher starting doses and incremental dosage titration of extended-release tacro limus to achieve target trough concentrations. We suggest a higher starting dose of 0.2 mg/kg/d for CYP3A5 expressers.

A pig model of chronic hepatitis E displaying persistent viremia and a downregulation of innate immune responses in the liver.

Hepatitis E virus (HEV) is a zoonotic virus transmitted by pig meat and responsible for chronic hepatitis E in immunocompromised patients. It has proved challenging to reproduce this disease in its natural reservoir. We therefore aimed to develop a pig model of chronic hepatitis E to improve the characterization of this disease. Ten pigs were treated with a tacrolimus-based regimen and intravenously inoculated with HEV. Tacrolimus trough concentration, HEV viremia, viral diversity, innate immune responses, liver histology, clinical disease and biochemical markers were monitored for 11 weeks post-infection (p.i.). HEV viremia persisted for 11 weeks p.i. HEV RNA was detected in the liver, small intestine, and colon at necropsy. Histological analysis revealed liver inflammation and fibrosis. Several mutations selected in the HEV genome were associated with compartmentalization in the feces and intestinal tissues, consistent with the hypothesis of extrahepatic replication in the digestive tract. Antiviral responses were characterized by a downregulation of IFN pathways in the liver, despite an upregulation of RIG-I and ISGs in the blood and liver. We developed a pig model of chronic hepatitis E that reproduced the major hallmarks of this disease. This model revealed a compartmentalization of HEV genomes in the digestive tract and a downregulation of innate immune responses in the liver. These original features highlight the relevance of our model for studies of the pathogenesis of chronic hepatitis E and for validating future treatments.

Machine Learning Models for Predicting Personalized Tacrolimus Stable Dosages in Pediatric Renal Transplant Patients

Tacrolimus, characterized by a narrow therapeutic index, significant toxicity, adverse effects, and interindividual variability, necessitates frequent therapeutic drug monitoring and dose adjustments in renal transplant recipients. This study aimed to compare machine learning (ML) models utilizing pharmacokinetic data to predict tacrolimus blood concentration. This prediction underpins crucial dose adjustments, emphasizing patient safety. The investigation focuses on a pediatric cohort. A subset served as the derivation cohort, creating the dose-prediction algorithm, while the remaining data formed the validation cohort. The study employed various ML models, including artificial neural network, RandomForestRegressor, LGBMRegressor, XGBRegressor, AdaBoostRegressor, BaggingRegressor, ExtraTreesRegressor, KNeighborsRegressor, and support vector regression, and their performances were compared. Although all models yielded favorable fit outcomes, the ExtraTreesRegressor (ETR) exhibited superior performance. It achieved measures of −0.161 for MPE, 0.995 for AFE, 1.063 for AAFE, and 0.8 for R2, indicating accurate predictions and meeting regulatory standards. The findings underscore ML’s predictive potential, despite the limited number of samples available. To address this issue, resampling was utilized, offering a viable solution within medical datasets for developing this pioneering study to predict tacrolimus trough concentration in pediatric transplant recipients.

Alterations in the Gut Microbiome in Liver Recipients with Post-Transplant Diabetes Mellitus

Post-transplant diabetes mellitus (PTDM) increases the risk of graft failure and death in liver transplant (LT) recipients. Experimental studies have indicated that enteric dysbiosis mediated by immunosuppressive tacrolimus (TAC) could contribute to glucose disorders, but no data on human recipients with PTDM have been reported. Here, by combining high-throughput shotgun metagenomics sequencing and metabolomics profiling, we characterized the intestinal microbiome (IM) in LT recipient cohort with or without PTDM and deciphered the potential relationship among IM, TAC dosage, and diabetes. By comparing with both non-PTDM and classical type 2 diabetes mellitus (T2DM), we identified microbial signatures of PTDM, which was characterized by the enriched Proteobacteria and decreased Bacteroidetes. Additionally, the altered microbes, as well as the microbial metabolomics, correlated with the dosage of TAC. Specifically, the levels of beneficial microbes associated with PTDM were lowered in recipients with the high TAC trough concentrations (> 5 ng∙mL–1) than those with low ones (< 5 ng∙mL–1), which was accompanied by reduced faecal metabolites involved in the biosynthesis of α-linolenic acid and arachidonic acid-lowering factors of developing T2DM. Moreover, these microbial signatures linked with the extent of glucose disorders in LT recipients. In summary, the faecal microbiome and metabolome differed between PTDM and non-PTDM patients, which were linked with TAC dosage. This study was the first to explore taxonomic alterations and bacterial gene functions to better understand the contribution of the IM to PTDM.

Generic Tacrolimus in Kidney Transplant Patients at Jordan University Hospital

Background: Tacrolimus is the immunosuppressive drug of choice for kidney transplant patients, but its cost is very high in the total drug cost for patients with renal disease. Lower drug costs can be achieved with generic tacrolimus. For this reason, the Ministry of Health mandated to implementation of a switch to generic form and so we wanted to evaluate whether a switch could be safely performed and to observe the effect of this on kidney function. Subjects and Methods: In this observational study, 28 stable kidney transplant patients taking Prograf®(Astellas) were switched to a generic Pangraf®(Pancea) in a 1:1 dose ratio and were followed up for 6 months. Plasma creatinine levels and trough concentrations of tacrolimus were recorded three times on Prograf® and weekly for 4 weeks, then monthly after conversion to Pangraf®. Results: Tacrolimus mean C0 levels were 6.97 ± 0.92 ng/mL before and 7.4 ± 1.23 ng/mL after conversion (P = 0.22). Mean serum creatinine values were 1.13 ± 0.53 mg/dL and 1.15 ± 0.54 mg/dL before and after conversion, respectively (P = 0.27). Conclusion: Switching from branded tacrolimus to generic tacrolimus seems possible and safe, but close monitoring is essential.

Impact of immunosuppression level on liver allograft fibrosis after pediatric liver transplantation: a retrospective cohort study.

Liver allograft fibrosis (LAF) is prevalent among children with long-term survival after liver transplantation (LT). The authors aimed to identify clinical risk factors, with a focus on the impact of immunosuppression (IS) level in the early post-transplant period on LAF. A retrospective study was conducted on pediatric LT recipients with at least 1-year of follow-up. Cox regression models were used to analyze risk factors associated with LAF, and landmark analysis was used to evaluate the impact of IS level on LAF. Longitudinal analysis was also conducted in patients with paired biopsies. A total of 139 patients involving 174 liver biopsies were included. With 2.3 to 5.9 years of follow-up, LAF was detected in 91.4% of patients (7.9% were significant), up to 88.2% of whom showed normal liver function. Episodes of acute rejection, biliary complications, cytomegalovirus infection, and prolonged cold ischemia time were independent risk factors. Besides, the risk of LAF in patients with relatively low IS levels at postoperative 1-3, 3-6, 6-12, and 12-36 months was higher than the counterparts. Especially, in patients with relatively high IS levels (mean tacrolimus trough concentration ≥5.1ng/ml) during postoperative 12-36 months, the risk of LAF was 67% lower in the short future ( P =0.006). In paired analysis, patients with increased IS levels were more likely to achieve fibrosis-reduction (HR=7.53, P =0.025). Mild to moderate LAF is common among pediatric LT recipients and can appear early and silently. Maintaining adequate levels of IS during 1-3 years after LT seems crucial to ensure protection against LAF.

Artificial Neural Network Analysis of Determinants of Tacrolimus Pharmacokinetics in Liver Transplant Recipients.

The efficacy and toxicity of tacrolimus are closely related to its trough blood concentrations. Identifying the influencing factors of pharmacokinetics of tacrolimus in the early postoperative period is conducive to the optimization of the individualized tacrolimus administration protocol and to help liver transplant (LT) recipients achieve the target blood concentrations. This study aimed to develop an artificial neural network (ANN) for predicting the blood concentration of tacrolimus soon after liver transplantation and for identifying determinants of the concentration based on Shapley additive explanation (SHAP). In this retrospective study, we enrolled 31 recipients who were first treated with liver transplantation from the Department of Liver Transplantation and Hepatic Surgery, the First Affiliated Hospital of Shandong First Medical University (Shandong Provincial Qianfoshan Hospital) from November 2020 to May 2021. The basic information, biochemical indexes, use of concomitant drugs, and genetic factors of organ donors and recipients were used for the ANN model inputs, and the output was the steady-state trough concentration (C0) of tacrolimus after oral administration in LT recipients. The ANN model was established to predict C0 of tacrolimus, SHAP was applied to the trained model, and the SHAP value of each input was calculated to analyze quantitatively the influencing factors for the output C0. A back-propagation ANN model with 3 hidden layers was established using deep learning. The mean prediction error was 0.27 ± 0.75 ng/mL; mean absolute error, 0.60 ± 0.52 ng/mL; correlation coefficient between predicted and actual C0 values, 0.9677; and absolute prediction error of all blood concentrations obtained by the ANN model, ≤3.0 ng/mL. The results indicated that the following factors had the most significant effect on C0: age, daily drug dose, genotype at CYP3A5 polymorphism rs776746 in both recipient and donor, and concomitant use of caspofungin. The predicted C0 value of tacrolimus in LT recipients increased in a dose-dependent manner when the daily dose exceeded 3 mg, whereas it decreased with age when LT recipients were older than 48 years. The predicted C0 was higher when recipients and donors had the genotype CYP3A5*3*3 than when they had the genotype CYP3A5*1. The predicted C0 value also increased with the use of caspofungin or Wuzhi capsule. The established ANN model can be used to predict the C0 value of tacrolimus in LT recipients with high accuracy and good predictive ability, serving as a reference for personalized treatment in the early stage after liver transplantation.

Effect of Tacrolimus Time in Therapeutic Range on Postoperative Recurrence in Patients Undergoing Liver Transplantation for Liver Cancer.

Liver cancer is the second highest cause of cancer-related deaths worldwide. It is commonly treated with liver transplantation, where tacrolimus is typically used as an antirejection immunosuppressant. The purpose of this study was to evaluate the effect of tacrolimus time in therapeutic range (TTR) on liver cancer recurrence in liver transplant recipients and to compare the performance of TTRs calculated according to the target ranges recommended in published guidelines. A total of 84 patients who underwent liver transplantation for liver cancer were retrospectively included. Tacrolimus TTR was calculated using linear interpolation from the date of transplantation until recurrence or the last follow-up according to target ranges recommended in the Chinese guideline and international expert consensus. Twenty-four recipients developed liver cancer recurrence after liver transplantation. The CTTR (TTR calculated according to the Chinese guideline) for the recurrence group was significantly lower than that of the nonrecurrence group (26.39% vs. 50.27%, P < 0.001), whereas the ITTR (TTR calculated according to the international consensus) was not significantly different between the two groups (47.81% vs. 56.37%, P = 0.165). Multivariate survival analysis revealed that age, microvascular invasion, hepatocellular carcinoma, CTTR, and mean tacrolimus trough concentration were independent predictors of liver cancer recurrence after liver transplantation. TTR predicts liver cancer recurrence in liver transplant recipients. The range of tacrolimus concentrations recommended in the Chinese guideline was more beneficial than that recommended in the international consensus for Chinese patients undergoing liver transplantation for liver cancer.

Using Prior Knowledge on Systems Through PBPK to Gain Further Insight into Routine Clinical Data on Trough Concentrations: The Case of Tacrolimus in Chronic Kidney Disease.

Routine therapeutic drug monitoring (TDM) relies heavily on measuring trough drug concentrations. Trough concentrations are affected not only by drug bioavailability and clearance, but also by various patient and disease factors and the volume of distribution. This often makes interpreting differences in drug exposure from trough data challenging. This study aimed to combine the advantages of top-down analysis of therapeutic drug monitoring data with bottom-up physiologically-based pharmacokinetic (PBPK) modeling to investigate the effect of declining renal function in chronic kidney disease (CKD) on the nonrenal intrinsic metabolic clearance ( CLint ) of tacrolimus as a case example. Data on biochemistry, demographics, and kidney function, along with 1167 tacrolimus trough concentrations for 40 renal transplant patients, were collected from the Salford Royal Hospital's database. A reduced PBPK model was developed to estimate CLint for each patient. Personalized unbound fractions, blood-to-plasma ratios, and drug affinities for various tissues were used as priors to estimate the apparent volume of distribution. Kidney function based on the estimated glomerular filtration rate ( eGFR ) was assessed as a covariate for CLint using the stochastic approximation of expectation and maximization method. At baseline, the median (interquartile range) eGFR was 45 (34.5-55.5) mL/min/1.73 m 2 . A significant but weak correlation was observed between tacrolimus CLint and eGFR (r = 0.2, P < 0.001). The CLint declined gradually (up to 36%) with CKD progression. Tacrolimus CLint did not differ significantly between stable and failing transplant patients. Kidney function deterioration in CKD can affect nonrenal CLint for drugs that undergo extensive hepatic metabolism, such as tacrolimus, with critical implications in clinical practice. This study demonstrates the advantages of combining prior system information (via PBPK) to investigate covariate effects in sparse real-world datasets.

Clinical pharmacokinetic study of tacrolimus in continuous intravenous administration for lung transplantation.

Tacrolimus is a cornerstone of immunosuppression after lung transplantation. However, there are no clear guidelines on how to administer the drug and the duration to achieve the required therapeutic range in the early phase of lung transplantation. This is a single-center cohort study of adult patients who had lung transplantation. Tacrolimus was administered beginning with a low dose of 0.01 mg/kg/day immediately after transplantation. In addition, the designated clinical pharmacist conducted a daily intervention with trough concentrations to achieve the target of 10-15 ng/mL. Time in the therapeutic range (TTRin, %), time to the therapeutic range (TTRto, days), and coefficient of variation (CoV) of tacrolimus were evaluated for the 2-week post-transplant period. A total of 67 adult patients who had received first-time lung transplantation were included in the analysis. The median percentage of tacrolimus TTRin was 35.7% (21.4-42.9%) for the 2-week postoperative period. The median day of TTRto was 7 days (5-9 days), and the median tacrolimus trough concentration was 10.02 ng/mL (7.87-12.26 ng/mL) for the 2-week postoperative period. The median CoV of tacrolimus was 49.7% (40.8-61.6%). Acute kidney injury following tacrolimus infusion occurred in 23 (34.3%) patients, but there was no neurotoxicity or acute cellular rejection within 1 month of the postoperative period. In conclusion, continuous intravenous administration with the daily measure and dose titration of tacrolimus trough concentrations allowed the therapeutic range of tacrolimus to be reached within 1 week without significant adverse events, although the pharmacokinetic parameters were highly variable over time.