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Ramdas S, Painho T, Vanegas MI, Famili DT, Lim MJ, Jungbluth H. Targeted Treatments for Myasthenia Gravis in Children and Adolescents. Paediatr Drugs 2024:10.1007/s40272-024-00649-3. [PMID: 39198371 DOI: 10.1007/s40272-024-00649-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 08/04/2024] [Indexed: 09/01/2024]
Abstract
Myasthenia gravis (MG) is an antibody-mediated disorder of the neuromuscular junction affecting children and adults. MG is a treatable condition with most patients requiring immunosuppression for disease control and/or remission. Juvenile myasthenia gravis (JMG) is rare in comparison with adult-onset MG but given the same underlying pathophysiology, treatment strategies are similar to those in adults. Until recently, there were only a few randomised controlled trials (RCTs) for MG treatments in adults and none in children, and management strategies were primarily based on expert consensus. In addition, treatment options for refractory MG cases have been severely limited, resulting in poor long-term quality of life in such patients due to the significant disease burden. Recently, there have been several RCTs focussing on novel therapeutic strategies with potentially promising outcomes, suggesting a change in MG management over the coming years and access to more effective and faster-acting drugs for MG patients. This paper will review current and new MG treatments including efgartigimod, eculizumab, rozanolixizumab, ravulizumab, and zilucoplan, with a focus on juvenile myasthenia gravis.
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Affiliation(s)
- Sithara Ramdas
- Department of Paediatrics, MDUK Neuromuscular Centre, University of Oxford, Oxford, UK
- Department of Paediatric Neurology, John Radcliffe Hospital, Oxford, UK
| | - Teresa Painho
- Department of Paediatrics, MDUK Neuromuscular Centre, University of Oxford, Oxford, UK
- Neurology Unit, Hospital Dona Estefânia, Unidade Local de Saúde São José, Centro Clínico Académico de Lisboa, Lisbon, Portugal
| | - Maria I Vanegas
- Department of Paediatric Neurology, Evelina London Children's Hospital, Guy's & St. Thomas' Hospital NHS Foundation Trust, Children's Neurosciences Centre, F02-Becket House, Lambeth Palace Road, London, SE1 7EU, UK
| | - Dennis T Famili
- Department of Paediatric Neurology, Evelina London Children's Hospital, Guy's & St. Thomas' Hospital NHS Foundation Trust, Children's Neurosciences Centre, F02-Becket House, Lambeth Palace Road, London, SE1 7EU, UK
| | - Ming J Lim
- Department of Paediatric Neurology, Evelina London Children's Hospital, Guy's & St. Thomas' Hospital NHS Foundation Trust, Children's Neurosciences Centre, F02-Becket House, Lambeth Palace Road, London, SE1 7EU, UK
- Women and Children's Health, Faculty of Life Sciences and Medicine (FoLSM), King's College London, London, UK
| | - Heinz Jungbluth
- Department of Paediatric Neurology, Evelina London Children's Hospital, Guy's & St. Thomas' Hospital NHS Foundation Trust, Children's Neurosciences Centre, F02-Becket House, Lambeth Palace Road, London, SE1 7EU, UK.
- Randall Centre for Cell and Molecular Biophysics, Muscle Signalling Section, Faculty of Life Sciences and Medicine (FoLSM), King's College London, London, UK.
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Heida A, Jager NGL, Aarnoutse RE, de Winter BCM, de Jong H, Keizer RJ, Cornelissen EAM, Ter Heine R. Model-informed dose optimization of mycophenolic acid in pediatric kidney transplant patients. Eur J Clin Pharmacol 2024:10.1007/s00228-024-03743-0. [PMID: 39153087 DOI: 10.1007/s00228-024-03743-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2024] [Accepted: 08/09/2024] [Indexed: 08/19/2024]
Abstract
PURPOSE We aimed to develop and evaluate a population PK model of mycophenolic acid (MPA) in pediatric kidney transplant patients to aid MPA dose optimization. METHODS Data were collected from pediatric kidney transplant recipients from a Dutch academic hospital (Radboudumc, the Netherlands). Pharmacokinetic model-building and model-validation analyses were performed using NONMEM. Subsequently, we externally evaluated the final model using data from another academic hospital. The final model was used to develop an optimized dosing regimen. RESULTS Thirty pediatric patients were included of whom 266 measured MPA plasma concentrations, including 20 full pharmacokinetic (PK) curves and 24 limited sampling curves, were available. A two-compartment model with a transition compartment for Erlang-type absorption best described the data. The final population PK parameter estimates were Ktr (1.48 h-1; 95% CI, 1.15-1.84), CL/F (16.0 L h-1; 95% CI, 10.3-20.4), Vc/F (24.9 L; 95% CI, 93.0-6.71E25), Vp/F (1590 L; 95% CI, 651-2994), and Q/F (36.2 L h-1; 95% CI, 9.63-74.7). The performance of the PK model in the external population was adequate. An optimized initial dose scheme based on bodyweight was developed. With the licensed initial dose, 35% of patients were predicted to achieve the target AUC, compared to 42% using the optimized scheme. CONCLUSION We have successfully developed a pharmacokinetic model for MPA in pediatric renal transplant patients. The optimized dosing regimen is expected to result in better target attainment early in treatment. It can be used in combination with model-informed follow-up dosing to further individualize the dose when PK samples become available.
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Affiliation(s)
- Astrid Heida
- Department of Pharmacy, Radboud Institute for Medical Innovation, Radboud University Medical Center, Nijmegen, The Netherlands.
| | - Nynke G L Jager
- Department of Pharmacy, Radboud Institute for Medical Innovation, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Rob E Aarnoutse
- Department of Pharmacy, Radboud Institute for Medical Innovation, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Brenda C M de Winter
- Department of Hospital Pharmacy, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Huib de Jong
- The Erasmus MC Transplant Institute, Erasmus University Medical Center, Rotterdam, The Netherlands
| | | | - Elisabeth A M Cornelissen
- Department of Pediatric Nephrology, Radboud University Medical Center, Amalia Children's Hospital, Nijmegen, The Netherlands
| | - Rob Ter Heine
- Department of Pharmacy, Radboud Institute for Medical Innovation, Radboud University Medical Center, Nijmegen, The Netherlands
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Sobiak J, Resztak M, Sikora W, Zachwieja J, Ostalska-Nowicka D. Liquid chromatography-tandem mass spectrometry method for mycophenolic acid and its glucuronide determination in saliva samples from children with nephrotic syndrome. Pharmacol Rep 2024; 76:600-611. [PMID: 38485859 PMCID: PMC11126467 DOI: 10.1007/s43440-024-00574-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 02/10/2024] [Accepted: 02/12/2024] [Indexed: 05/25/2024]
Abstract
BACKGROUND Saliva sampling is one of the methods of therapeutic drug monitoring for mycophenolic acid (MPA) and its metabolite, mycophenolic acid glucuronide (MPAG). The study describes the liquid chromatography tandem mass spectrometry (LC-MS/MS) method developed for saliva MPA and MPAG determination in children with nephrotic syndrome. METHODS The mobile phase consisted of methanol and water at gradient flow, both with 0.1% formic acid. Firstly, 100 µL of saliva was evaporated at 45 °C for 2 h to dryness, secondly, it was reconstituted in the mobile phase, and finally 10 µL was injected into the LC-MS/MS system. Saliva from ten children with nephrotic syndrome treated with mycophenolate mofetil was collected with Salivette®. RESULTS For MPA and MPAG, within the 2-500 ng/mL range, the method was selective, specific, accurate and precise within-run and between-run. No carry-over and matrix effects were observed. Stability tests showed that MPA and MPAG were stable in saliva samples if stored for 2 h at room temperature, 18 h at 4 °C, and at least 5 months at - 80 °C as well as after three freeze-thaw cycles, in a dry extract for 16 h at 4 °C, and for 8 h at 15 °C in the autosampler. The analytes were not adsorbed onto Salivette® cotton swabs. For concentrations above 500 ng/mL, the samples may be diluted twofold. In children, saliva MPA and MPAG were within the ranges of 4.6-531.8 ng/mL and 10.7-183.7 ng/mL, respectively. CONCLUSIONS The evaluated LC-MS/MS method has met the validation requirements for saliva MPA and MPAG determination in children with nephrotic syndrome. Further studies are needed to explore plasma-saliva correlations and assess their potential contribution to MPA monitoring.
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Affiliation(s)
- Joanna Sobiak
- Department of Physical Pharmacy and Pharmacokinetics, Poznan University of Medical Sciences, 3 Rokietnicka Street, 60-806, Poznan, Poland.
| | - Matylda Resztak
- Department of Physical Pharmacy and Pharmacokinetics, Poznan University of Medical Sciences, 3 Rokietnicka Street, 60-806, Poznan, Poland
| | - Weronika Sikora
- Department of Physical Pharmacy and Pharmacokinetics, Poznan University of Medical Sciences, 3 Rokietnicka Street, 60-806, Poznan, Poland
| | - Jacek Zachwieja
- Department of Pediatric Nephrology and Hypertension, Poznan University of Medical Sciences, Poznan, Poland
| | - Danuta Ostalska-Nowicka
- Department of Pediatric Nephrology and Hypertension, Poznan University of Medical Sciences, Poznan, Poland
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Newland DM, Pak JL, Ali R, Herzog T, Nemeth TL, Tressel W, Kronmal RA, Knorr LR, Albers EL, Friedland-Little JM, Ahmed H, Kemna MS, Hong BJ, Spencer K, Law YM. Mycophenolic acid therapeutic drug monitoring using area under the curve in pediatric heart transplant recipients. Clin Transplant 2023; 37:e15087. [PMID: 37526562 DOI: 10.1111/ctr.15087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2023] [Revised: 06/10/2023] [Accepted: 07/24/2023] [Indexed: 08/02/2023]
Abstract
INTRODUCTION Pharmacokinetics of mycophenolic acid (MPA) display substantial interpatient variability, with up to 10-fold difference of exposure in individual patients under a fixed-dose regimen. MPA trough level (C0) monitoring is common in clinical practice but has not proven sufficiently informative in predicting MPA exposure or patient outcomes, especially in children. No limited sampling strategies (LSSs) have been generated from pediatric heart transplant (HTx) recipients to estimate MPA AUC. METHODS Single-center, observational analysis of 135 de novo pediatric HTx recipients ≤21 years old who underwent MPA AUC between 2011 and 2021. RESULTS Median age was 4 years (IQR .6-12.1). Median time from transplant to MPA AUC sampling was 15 days (IQR 11-19). MMF doses (mg or mg/day) had low, negative Pearson correlation coefficients (r) while doses adjusted for weight or body surface area had low correlation with Trapezoidal MPA AUC0-24 h (r = .3 and .383, respectively). MPA C0 had weak association (r = .451) with Trapezoidal MPA AUC0-24 h . LSS with two pharmacokinetic sampling time points at 90 (C3 ) and 360 (C5 ) min after MMF administration (estimated AUC0-24 h = 32.82 + 4.12 × C3 + 11.53 × C5 ) showed strong correlation with Trapezoidal MPA AUC0-24 h (r = .87). CONCLUSION MMF at fixed or weight-adjusted doses, as well as MPA trough levels, correlate poorly with MPA AUC0-24 h . We developed novel LSSs to estimate Trapezoidal MPA AUC from a large cohort of pediatric HTx recipients. Validation of our LSSs should be completed in a separate cohort of pediatric HTx recipients.
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Affiliation(s)
- David M Newland
- Department of Pharmacy, Seattle Children's Hospital, Seattle, Washington, USA
- School of Pharmacy, University of Washington, Seattle, Washington, USA
| | - Jennifer L Pak
- Department of Pharmacy, Seattle Children's Hospital, Seattle, Washington, USA
- School of Pharmacy, University of Washington, Seattle, Washington, USA
| | - Reda Ali
- Department of Pharmacy, Seattle Children's Hospital, Seattle, Washington, USA
- School of Pharmacy, University of Washington, Seattle, Washington, USA
| | | | - Thomas L Nemeth
- Department of Pharmacy, Seattle Children's Hospital, Seattle, Washington, USA
- School of Pharmacy, University of Washington, Seattle, Washington, USA
| | - William Tressel
- Department of Biostatistics, University of Washington, Seattle, Washington, USA
| | - Richard A Kronmal
- Department of Biostatistics, University of Washington, Seattle, Washington, USA
| | - Lisa R Knorr
- Department of Pharmacy, Seattle Children's Hospital, Seattle, Washington, USA
- School of Pharmacy, University of Washington, Seattle, Washington, USA
| | - Erin L Albers
- Pediatric Cardiology, Seattle Children's Hospital, Seattle, Washington, USA
- School of Medicine, University of Washington, Seattle, Washington, USA
| | - Joshua M Friedland-Little
- Pediatric Cardiology, Seattle Children's Hospital, Seattle, Washington, USA
- School of Medicine, University of Washington, Seattle, Washington, USA
| | - Humera Ahmed
- Pediatric Cardiology, Seattle Children's Hospital, Seattle, Washington, USA
- School of Medicine, University of Washington, Seattle, Washington, USA
| | - Mariska S Kemna
- Pediatric Cardiology, Seattle Children's Hospital, Seattle, Washington, USA
- School of Medicine, University of Washington, Seattle, Washington, USA
| | - Borah J Hong
- Pediatric Cardiology, Seattle Children's Hospital, Seattle, Washington, USA
- School of Medicine, University of Washington, Seattle, Washington, USA
| | - Kathryn Spencer
- Pediatric Cardiology, Seattle Children's Hospital, Seattle, Washington, USA
| | - Yuk M Law
- Pediatric Cardiology, Seattle Children's Hospital, Seattle, Washington, USA
- School of Medicine, University of Washington, Seattle, Washington, USA
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Rong Y, Wichart J, Hamiwka L, Kiang TKL. Significant Effects of Renal Function on Mycophenolic Acid Total Clearance in Pediatric Kidney Transplant Recipients with Population Pharmacokinetic Modeling. Clin Pharmacokinet 2023; 62:1289-1303. [PMID: 37493886 DOI: 10.1007/s40262-023-01280-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/21/2023] [Indexed: 07/27/2023]
Abstract
BACKGROUND AND OBJECTIVES Mycophenolic acid (MPA) is an immunosuppressant commonly prescribed in pediatric kidney transplantation to prevent graft rejection. Large variabilities in MPA plasma exposures have been observed in this population, which could result in severe adverse effects. The majority of the MPA pharmacokinetic data have been reported in adult populations, whereas information in pediatric patients is still very limited. The objective of this study was to establish a novel, nonlinear mixed-effects model for MPA and investigate the clinical variables affecting MPA population pharmacokinetics in pediatric kidney transplant recipients. METHODS Data were collected retrospectively from pediatric kidney transplant patients (≤ 18 years when MPA concentrations were initially collected; on oral administration of mycophenolate mofetil) in Calgary, Alberta, Canada. Nonlinear mixed-effect modeling was conducted using stochastic approximation expectation-maximization in Monolix 2021R2 (Lixoft SAS, France) to determine population pharmacokinetic estimates, interindividual variabilities, and interoccasional variabilities. Covariate models were constructed using the Model Proposal function in Monolix in conjunction with a systematic stepwise inclusion/elimination protocol. The best model was selected based on objective function values, relative standard errors, goodness-of-fit plots, prediction-corrected visual predictive checks, and numerical predictive checks. RESULTS A total of 50 pediatric kidney transplant patients (25 female) with 219 MPA plasma concentration-time profiles were included. The average age (± standard deviation) and posttransplant time for the sample population were 12.8 ± 4.8 years and 762 ± 1160 days, respectively. The majority of study subjects (i.e., > 85% based on all occasions) were co-administered tacrolimus. A two-compartment, first-order absorption with lag time and linear elimination structural model with lognormal distributed proportional residual errors best described the MPA concentration-time data. The absorption rate constant (2.52 h-1 or 0.042 min-1), lag time (0.166 h or 9.96 min), volumes of distributions of the central (22.8 L) and peripheral (216 L) compartments, and intercompartment clearance (17.6 L h-1 or 0.293 L min-1) were consistent with literature values; whereas total MPA clearance (0.72 L h-1 or 0.012 L min-1) was relatively reduced, likely due to the general lack of cyclosporine interactions and the stabilized graft functions from significantly longer posttransplant time in our sample population. Of the clinical variables tested, only estimated glomerular filtration rate (eGFR) was identified a significant covariate affecting total MPA clearance with a positive, exponential relationship. The final population pharmacokinetic model was successfully evaluated/validated using a variety of complementary methods. CONCLUSION We have successfully constructed and validated a novel population pharmacokinetic model of MPA in pediatric kidney transplant patients. A positive, nonlinear relationship between eGFR and total MPA clearance identified in our model is likely attributed to multiple concurrent mechanisms, which warrant further systematic investigations.
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Affiliation(s)
- Yan Rong
- Faculty of Pharmacy and Pharmaceutical Sciences, Katz Group Centre for Pharmacy and Health Research, University of Alberta, Room 3-142D, 11361-87 Avenue, Edmonton, AB, T6G 2E1, Canada
| | - Jenny Wichart
- Alberta Health Services, Pharmacy Services, Calgary, AB, Canada
| | - Lorraine Hamiwka
- Department of Pediatrics, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Tony K L Kiang
- Faculty of Pharmacy and Pharmaceutical Sciences, Katz Group Centre for Pharmacy and Health Research, University of Alberta, Room 3-142D, 11361-87 Avenue, Edmonton, AB, T6G 2E1, Canada.
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Kocur A, Rubik J, Czarnowski P, Czajkowska A, Marszałek D, Sierakowski M, Górska M, Pawiński T. Therapeutic drug monitoring of mycophenolic acid (MPA) using volumetric absorptive microsampling (VAMS) in pediatric renal transplant recipients: ultra-high-performance liquid chromatography-tandem mass spectrometry analytical method development, cross-validation, and clinical application. Pharmacol Rep 2023:10.1007/s43440-023-00509-w. [PMID: 37452967 PMCID: PMC10374821 DOI: 10.1007/s43440-023-00509-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Revised: 07/03/2023] [Accepted: 07/04/2023] [Indexed: 07/18/2023]
Abstract
BACKGROUND Mycophenolic acid (MPA) is widely used in posttransplant pharmacotherapy for pediatric patients after renal transplantation. Volumetric absorptive microsampling (VAMS) is a recent approach for sample collection, particularly during therapeutic drug monitoring (TDM). The recommended matrix for MPA determination is plasma (PL), and conversion between capillary-blood VAMS samples and PL concentrations is required for the appropriate interpretation of the results. METHODS This study aimed to validate and develop a UHPLC-MS/MS method for MPA quantification in whole blood (WB), PL, and VAMS samples, with cross and clinical validation based on regression calculations. Methods were validated in the 0.10-15 µg/mL range for trough MPA concentration measurement according to the European Medicines Agency (EMA) guidelines. Fifty pediatric patients treated with MPA after renal transplantation were included in this study. PL and WB samples were obtained via venipuncture, whereas VAMS samples were collected after the fingerstick. The conversion from VAMSMPA to PLMPA concentration was performed using formulas based on hematocrit values and a regression model. RESULTS LC-MS/MS methods were successfully developed and validated according to EMA guidelines. The cross-correlation between the methods was evaluated using Passing-Bablok regression, Bland-Altman bias plots, and predictive performance calculations. Clinical validation of the developed method was successfully performed, and the formula based on regression was successfully validated for VAMSMPA to PLMPA concentration and confirmed on an independent group of samples. CONCLUSIONS This study is the first development of a triple matrix-based LC-MS/MS method for MPA determination in the pediatric population after renal transplantation. For the first time, the developed methods were cross-validated with routinely used HPLC-DAD protocol.
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Affiliation(s)
- Arkadiusz Kocur
- Department of Drug Chemistry, Medical University of Warsaw, 1 Banacha St, 02-091, Warsaw, Poland.
- Pharmacokinetics Laboratory, Department of Biochemistry, Radioimmunology, and Experimental Medicine, The Children's Memorial Health Institute, Dzieci Polskich 20, 04-730, Warsaw, Poland.
| | - Jacek Rubik
- Department of Nephrology, Kidney Transplantation, and Arterial Hypertension, The Children's Memorial Health Institute, Dzieci Polskich 20, 04-730, Warsaw, Poland
| | - Paweł Czarnowski
- Department of Genetics, Maria Sklodowska-Curie National Research Institute of Oncology, Roentgena 5, 02-781, Warsaw, Poland
| | - Agnieszka Czajkowska
- Pharmacokinetics Laboratory, Department of Biochemistry, Radioimmunology, and Experimental Medicine, The Children's Memorial Health Institute, Dzieci Polskich 20, 04-730, Warsaw, Poland
| | - Dorota Marszałek
- Department of Drug Chemistry, Medical University of Warsaw, 1 Banacha St, 02-091, Warsaw, Poland
| | - Maciej Sierakowski
- Institute of Biological Sciences, Cardinal Stefan Wyszynski University, 1/3 Kazimierza Wóycickiego St, 01-938, Warsaw, Poland
| | - Marta Górska
- Pharmacokinetics Laboratory, Department of Biochemistry, Radioimmunology, and Experimental Medicine, The Children's Memorial Health Institute, Dzieci Polskich 20, 04-730, Warsaw, Poland
| | - Tomasz Pawiński
- Department of Drug Chemistry, Medical University of Warsaw, 1 Banacha St, 02-091, Warsaw, Poland
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Puliyanda D, Barday Z, Barday Z, Freedman A, Todo T, Chen AKC, Davidson B. Children Are Not Small Adults: Similarities and Differences in Renal Transplantation Between Adults and Pediatrics. Semin Nephrol 2023; 43:151442. [PMID: 37949683 DOI: 10.1016/j.semnephrol.2023.151442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2023]
Abstract
Kidney transplantation is the treatment of choice for all patients with end-stage kidney disease, including pediatric patients. Graft survival in pediatrics was lagging behind adults, but now is comparable with the adult cohort. Although many of the protocols have been adopted from adults, there are issues unique to pediatrics that one should be aware of to take care of this population. These issues include recipient size consideration, increased incidence of viral infections, problems related to growth, common occurrence of underlying urological issues, and psychosocial issues. This article addresses the similarities and differences in renal transplantation, from preparing a patient for transplant, the transplant process, to post-transplant complications.
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Affiliation(s)
- Dechu Puliyanda
- Pediatric Nephrology and Comprehensive Transplant Program, Cedars Sinai Medical Center, Los Angeles, CA.
| | - Zibya Barday
- Department of Nephrology and Hypertension, Groote Schuur Hospital, University of Cape Town, Cape Town, South Africa
| | - Zunaid Barday
- Department of Nephrology and Hypertension, Groote Schuur Hospital, University of Cape Town, Cape Town, South Africa
| | - Andrew Freedman
- Pediatric Nephrology and Comprehensive Transplant Program, Cedars Sinai Medical Center, Los Angeles, CA
| | - Tsuyoshi Todo
- Pediatric Nephrology and Comprehensive Transplant Program, Cedars Sinai Medical Center, Los Angeles, CA
| | - Allen Kuang Chung Chen
- Pediatric Nephrology and Comprehensive Transplant Program, Cedars Sinai Medical Center, Los Angeles, CA
| | - Bianca Davidson
- Department of Nephrology and Hypertension, Groote Schuur Hospital, University of Cape Town, Cape Town, South Africa
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Sobiak J, Resztak M, Banasiak J, Zachwieja J, Ostalska-Nowicka D. High-performance liquid chromatography with fluorescence detection for mycophenolic acid determination in saliva samples. Pharmacol Rep 2023; 75:726-736. [PMID: 36905501 PMCID: PMC10007665 DOI: 10.1007/s43440-023-00474-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 03/01/2023] [Accepted: 03/02/2023] [Indexed: 03/12/2023]
Abstract
BACKGROUND For therapeutic drug monitoring (TDM) of mycophenolic acid (MPA), which is frequently proposed, saliva might be a suitable and easy-to-obtain biological matrix. The study aimed to validate an HPLC method with fluorescence detection for determining mycophenolic acid in saliva (sMPA) in children with nephrotic syndrome. METHODS The mobile phase was composed of methanol and tetrabutylammonium bromide with disodium hydrogen phosphate (pH 8.5) at a 48:52 ratio. To prepare the saliva samples, 100 µL of saliva, 50 µL of calibration standards, and 50 µL of levofloxacin (used as an internal standard) were mixed and evaporated to dryness at 45 °C for 2 h. The resulting dry extract was reconstituted in the mobile phase and injected into the HPLC system after centrifugation. Saliva samples from study participants were collected using Salivette® devices. RESULTS The method was linear within the range of 5-2000 ng/mL, was selective with no carry-over effect and met the acceptance criteria for within-run and between-run accuracy and precision. Saliva samples can be stored for up to 2 h at room temperature, for up to 4 h at 4 °C, and for up to 6 months at - 80 °C. MPA was stable in saliva after three freeze-thaw cycles, in dry extract for 20 h at 4 °C, and for 4 h in the autosampler at room temperature. MPA recovery from Salivette® cotton swabs was within the range of 94-105%. The sMPA concentrations in the two children with nephrotic syndrome who were treated with mycophenolate mofetil were within 5-112 ng/mL. CONCLUSIONS The sMPA determination method is specific, selective, and meets the validation requirements for analytic methods. It may be used in children with nephrotic syndrome; however further studies are required to investigate focusing on sMPA and the correlation between sMPA and total MPA and its possible contribution to MPA TDM is required.
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Affiliation(s)
- Joanna Sobiak
- Department of Physical Pharmacy and Pharmacokinetics, Poznan University of Medical Sciences, 3 Rokietnicka Street, 60-806, Poznan, Poland.
| | - Matylda Resztak
- Department of Physical Pharmacy and Pharmacokinetics, Poznan University of Medical Sciences, 3 Rokietnicka Street, 60-806, Poznan, Poland
| | - Joanna Banasiak
- Department of Physical Pharmacy and Pharmacokinetics, Poznan University of Medical Sciences, 3 Rokietnicka Street, 60-806, Poznan, Poland
| | - Jacek Zachwieja
- Department of Pediatric Nephrology and Hypertension, Poznan University of Medical Sciences, Poznan, Poland
| | - Danuta Ostalska-Nowicka
- Department of Pediatric Nephrology and Hypertension, Poznan University of Medical Sciences, Poznan, Poland
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Sobiak J, Żero P, Zachwieja J, Ostalska-Nowicka D, Pawiński T. Limited sampling strategy to predict free mycophenolic acid area under the concentration-time curve in paediatric patients with nephrotic syndrome. Clin Exp Pharmacol Physiol 2023; 50:486-496. [PMID: 36846865 DOI: 10.1111/1440-1681.13765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 02/17/2023] [Accepted: 02/22/2023] [Indexed: 03/01/2023]
Abstract
In paediatric patients, there is no data on the recommended area under the concentration-time curve from 0 to 12 h (AUC0-12 ) for free mycophenolic acid (fMPA), which is the active form of the drug, responsible for the pharmacological effect. We decided to establish the limited sampling strategy (LSS) for fMPA for its use in MPA therapeutic monitoring in children with nephrotic syndrome treated with mycophenolate mofetil (MMF). This study included 23 children (aged 11 ± 4 years) from whom eight blood samples were collected within 12 h after MMF administration. The fMPA was determined using the high-performance liquid chromatography with fluorescence detection method. LSSs were estimated with the use of R software and bootstrap procedure. The best model was chosen based on a number of profiles with AUC predicted within ± 20% of AUC0-12 (good guess), r2 , mean prediction error (%MPE) of ±10% and mean absolute error (%MAE) of less than 25%. The fMPA AUC0-12 was 0.1669 ± 0.0697 μg h/mL and the free fraction was within 0.16%-0.81%. In total, there were 92 equations developed of which five fulfilled the acceptance criteria for %MPE, %MAE, good guess >80% and r2 > 0.900. These equations consisted of three time points: model 1 (C1 , C2 , C6 ), model 2 (C1 , C3 , C6 ), model 3 (C1 , C4 , C6 ), model 5 (C0 , C1 , C2 ), and model 6 (C1 , C2 , C9 ). Although blood sampling up to 9 h after MMF dosing is impractical, it is crucial to include C6 or C9 in LSS to assess fMPA AUCpred correctly. The most practical fMPA LSS, which fulfilled the acceptance criteria in the estimation group, was fMPA AUCpred = 0.040 + 2.220 × C0 + 1.130 × C1 + 1.742 × C2 . Further studies should define the recommended fMPA AUC0-12 value in children with nephrotic syndrome.
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Affiliation(s)
- Joanna Sobiak
- Department of Physical Pharmacy and Pharmacokinetics, Poznan University of Medical Sciences, Poznań, Poland
| | - Paweł Żero
- Department of Drug Chemistry, Medical University of Warsaw, Warsaw, Poland
| | - Jacek Zachwieja
- Department of Pediatric Nephrology and Hypertension, Poznan University of Medical Sciences, Poznań, Poland
| | - Danuta Ostalska-Nowicka
- Department of Pediatric Nephrology and Hypertension, Poznan University of Medical Sciences, Poznań, Poland
| | - Tomasz Pawiński
- Department of Drug Chemistry, Medical University of Warsaw, Warsaw, Poland
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10
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Population Pharmacokinetics of Enteric-Coated Mycophenolate Sodium in Children after Renal Transplantation and Initial Dosage Recommendation Based on Body Surface Area. COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 2022; 2022:1881176. [PMID: 36124167 PMCID: PMC9482478 DOI: 10.1155/2022/1881176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 05/21/2022] [Accepted: 08/12/2022] [Indexed: 11/29/2022]
Abstract
Objective Enteric-coated mycophenolate sodium (EC-MPS) is widely used in renal transplant recipients. There is a lack of study on the pharmacokinetics of this drug in children. This study is aimed at developing a population pharmacokinetic model of mycophenolic acid in children who were treated with EC-MPS after renal transplantation and to recommend initial dosage. Methods Pediatric patients who had undergone renal transplantation and received EC-MPS were included. Data on demographic characteristics, biochemical tests, blood routine examinations, mycophenolic acid plasma concentrations, dosing amount and frequency of EC-MPS, and coadministered medications were retrospective collected from June 2018 to August 2019. Nonlinear mixed effect modeling methods were adopted to develop a population pharmacokinetic model with the data above. Additional data from September 2019 to July 2020 were used to validate the model. Simulations under different dosage regimen were conducted to evaluate the percentage of target attainment (PTA, AUC0-12h 30–60 mg·h/L). Results A total of 96 pediatric patients aged at 13.3 (range 4.3–18.0) years were included in the modeling group. Data from 32 patients aged at 13.0 (range 3.6–18.3) years were used to validate the model. A one-compartment model with a double extravascular absorption was developed. Body surface area (BSA) was added as a covariate. Simulations showed that for different dosing regimens, the highest percentage of target attainment is around 50%. The best dosing regimen is 180 mg every 48 hours for patients with BSA of 0.22–0.46 m2, 180 mg every 24 hours with BSA of 0.47–0.67 m2, 180 mg every 24 hours with BSA of 0.68–0.96 m2, 360 mg every 24 hours with BSA of 0.97–1.18 m2, 540 mg every 24 hours with BSA of 1.19–1.58 m2, and 360 mg every 12 hours with BSA of 1.59–2.03 m2. Conclusion BSA could affect the area under curve of mycophenolic acid with the administration of EC-MPS. Considering the inflexibility of the dosage form, future development of smaller amount per tablet suitable for younger children with BSA < 1.19 m2 is warranted.
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11
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Mycophenolate mofetil-induced hypogammaglobulinemia and infectious disease susceptibility in pediatric patients with chronic rheumatic disorders: a monocentric retrospective study. Eur J Pediatr 2022; 181:3439-3448. [PMID: 35834043 DOI: 10.1007/s00431-022-04560-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 07/04/2022] [Accepted: 07/05/2022] [Indexed: 11/03/2022]
Abstract
UNLABELLED Mycophenolate mofetil (MMF) is an immunosuppressive drug used for the treatment of autoimmune rheumatological diseases. To test the risk of hypothetical drug-induced hypogammaglobulinemia, the aim of this study was to report the trend of the immunoglobulin (Ig) values and of the infectious diseases in children treated with MMF. This study retrospectively evaluated demographic, clinical, and laboratory data of a cohort of patients affected by a chronic rheumatic disease receiving MMF, followed at the Rheumatology Unit of Meyer Children Hospital, Florence. A total of 29 pediatric patients were enrolled. In patients with normal values of immunoglobulins at the baseline, treatment with MMF resulted in a statistically significant reduction of the IgG levels (p = 0.0058) and in a decrease of IgM levels not reaching statistical significance. The levels of IgA were not affected. During the follow-up, seven patients developed an humoral immune defect. The univariate analysis did not identify any risk factors related to the iatrogenic hypogammaglobulinemia. The infection rate during MMF therapy was significantly higher than the 12-month period before therapy (p = 0.006), while the severe infections did not significantly increase (p = 0.1818), even considering only the patients with hypogammaglobulinemia. CONCLUSION In pediatric patients with chronic rheumatic diseases, immunological first level tests and serological analyses to screen the protection against the common childhood pathogens are suggested before starting an immunosuppressive drug. These patients should also complete the vaccination schedule. In patients treated with MMF a strict monitoring of Ig is required during treatment and after discontinuation of the drug. WHAT IS KNOWN • MMF is an immunosuppressive drug initially used for the treatment of the graft-versus-host disease. • Mycophenolic acid is an inhibitor of inosine-5'-monophosphate dehydrogenase, expressed in lymphocytes; therefore, MMF could impair the immune system function. WHAT IS NEW • MMF resulted in a reduction of IgG and an increase of not severe infection rate. • Immunological first level tests, including Ig, lymphocyte subpopulations, and antibody response to vaccines, are suggested in pediatric patients before starting MMF; a strict monitoring of Ig is important before, during, and after MMF treatment.
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12
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Liu Y, Zhang H, Li J, Liu L, Wu C, Fu Q, Huang M, Chen X, Wang C, Chen P. Pharmacokinetics of free and total mycophenolic acid in paediatric and adult renal transplant recipients: Exploratory analysis of the effects of clinical factors and gene variants. Basic Clin Pharmacol Toxicol 2022; 131:60-73. [PMID: 35567285 DOI: 10.1111/bcpt.13743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 04/20/2022] [Accepted: 05/10/2022] [Indexed: 11/29/2022]
Abstract
Clinical and genetic influencing factors on free fraction of mycophenolic acid (MPA) have rarely been discussed. The present study investigated whether the clinical and genetic factors could explain the variability in the pharmacokinetics of free MPA (fMPA) and total MPA (tMPA) in Chinese paediatric and adult renal transplant recipients. Twenty-eight paediatric and 31 adult patients were enrolled, and the concentrations of tMPA and fMPA were determined at 0 h (predose) and 0.5, 1, 1.5, 2, 4, 5, 8, 9, 10 and 12 h after mycophenolate mofetil administration. Genetic polymorphisms of UGTs (rs671448, rs1042597, rs2741049, rs62298861, rs7439366, rs12233719) and ABCC2 (rs717620) were simultaneously determined. The clinical and genetic data were analysed and reported. tMPA and fMPA concentrations adjusted for dose per body weight were consistently higher in adults than in paediatric patients. In the paediatric group, only albumin and time after transplantation correlated significantly with the MPA-free fraction variation, which could explain 32.4% of the variability. Besides, ABCC2 polymorphism, albumin and time after transplantation correlated significantly with the MPA-free fraction variation in adults, which could explain 56.9% of the variability. The influencing factors in the paediatric group are different from those in adults, which may be due to age-related transporter expression.
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Affiliation(s)
- Yan Liu
- Department of Pharmacy, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China.,Department of Pharmacy, First hospital of Nanchang, Nanchang, China.,Institule of Clinical Pharmacology, School of Pharmaceutical sciences, Sun Yat-sen University, Guangzhou, China
| | - Huanxi Zhang
- Organ Transplant Center, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Jun Li
- Organ Transplant Center, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Longshan Liu
- Organ Transplant Center, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Chenglin Wu
- Organ Transplant Center, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Qian Fu
- Organ Transplant Center, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Min Huang
- Institule of Clinical Pharmacology, School of Pharmaceutical sciences, Sun Yat-sen University, Guangzhou, China
| | - Xiao Chen
- Department of Pharmacy, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Changxi Wang
- Organ Transplant Center, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Pan Chen
- Department of Pharmacy, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
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13
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Beaulieu Q, Zhang D, Melki I, Baudouin V, Goldwirst L, Woillard JB, Jacqz-Aigrain E. Pharmacokinetics of mycophenolic acid and external evaluation of two limited sampling strategies of drug exposure in patients with juvenile systematic lupus erythematosus. Eur J Clin Pharmacol 2022; 78:1003-1010. [PMID: 35294622 DOI: 10.1007/s00228-022-03295-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 02/14/2022] [Indexed: 11/30/2022]
Abstract
INTRODUCTION Mycophenolate mofetil (MMF), a pro-drug of mycophenolic acid (MPA), has become a major therapeutic option in juvenile systemic lupus erythematosus (jSLE). Monitoring MPA exposure using area under curve (AUC) has proved its value to increase efficacy and safety in solid organ transplantation both in children and adults, but additional data are required in patients with autoimmune diseases. In order to facilitate MMF therapeutic drug monitoring (TDM) in children, Bayesian estimators (BE) of MPA AUC0-12 h using limited sampling strategies (LSS) have been developed. Our aim was to conduct an external validation of these LSS using rich pharmacokinetics and compare their predictive performance. METHODS Pharmacokinetic blood samples were collected from jSLE treated by MMF and MPA plasma concentrations were determined using high-performance liquid chromatography system with ultraviolet detection (HPLC-UV). Individual AUC0-12 h at steady state was calculated using the trapezoid rule and compared with two LSS: (1) ISBA, a two-stage Bayesian approach developed for jSLE and (2) ADAPT, a non-linear mixed effects model with a parametric maximum likelihood approach developed with data from renal transplanted adults. RESULTS We received 41 rich pediatric PK at steady state from jSLE and calculated individual AUC0-12 h. The external validation MPA AUC0-12 h was conducted by selecting the concentration-time points adapted to ISBA and ADAPT: (1) ISBA showed good accuracy (bias: - 0.8 mg h/L), (2) ADAPT resulted in a bias of 6.7 mg L/h. The corresponding relative root mean square prediction error (RSME) was 23% and 43% respectively. CONCLUSION According to our external validation of two LSS of drug exposure, the ISBA model is recommended for Bayesian estimation of MPA AUC0-12 h in jSLE. In the literature focusing on MMF TDM, an efficacy cut-off for MPA AUC0-12 h between 30 and 45 mg h/L is proposed in jSLE but this requires additional validation.
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Affiliation(s)
- Quentin Beaulieu
- Paediatric Pharmacology, Department of Biological Pharmacology, Saint-Louis University Hospital, Assistance Publique - Hôpitaux de Paris, Paris, France
| | - Daolun Zhang
- Paediatric Pharmacology, Department of Biological Pharmacology, Saint-Louis University Hospital, Assistance Publique - Hôpitaux de Paris, Paris, France
| | - Isabelle Melki
- General Pediatrics, Infectious Disease and Internal Medicine Department, Robert Debre University Hospital, Reference Center for Rheumatic, AutoImmune and Systemic Diseases in Children (RAISE), AP-HP, Paris, France.,Pediatric Hematology-Immunology and Rheumatology Department, Necker-Enfants Malades University Hospital, Reference center for Rheumatic, AutoImmune and Systemic Diseases in Children (RAISE), AP-HP, Paris, France.,Laboratory of Neurogenetics and Neuroinflammation, Imagine Institute, Paris, France
| | - Véronique Baudouin
- Department of Pediatric Nephrology, Robert Debré University Hospital, Assistance Publique - Hôpitaux de Paris, Paris, France
| | - Lauriane Goldwirst
- Paediatric Pharmacology, Department of Biological Pharmacology, Saint-Louis University Hospital, Assistance Publique - Hôpitaux de Paris, Paris, France
| | - Jean-Baptiste Woillard
- IPPRITT, INSERM, U1248, Limoges, France.,IPPRITT, University of Limoges, Limoges, France.,Department of Pharmacology and Toxicology, CHU Limoges, Limoges, France
| | - Evelyne Jacqz-Aigrain
- Paediatric Pharmacology, Department of Biological Pharmacology, Saint-Louis University Hospital, Assistance Publique - Hôpitaux de Paris, Paris, France. .,University of Paris, Paris, France. .,Department of Biological Pharmacology, Saint-Louis University Hospital, Assistance Publique - Hôpitaux de Paris, FranceHôpital Saint-Louis, Assistance Publique Hôpitaux de Paris, 1 avenue Charles Vellefaux, Paris, 75010, France.
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Sobiak J, Resztak M. A Systematic Review of Multiple Linear Regression-Based Limited Sampling Strategies for Mycophenolic Acid Area Under the Concentration-Time Curve Estimation. Eur J Drug Metab Pharmacokinet 2021; 46:721-742. [PMID: 34480746 PMCID: PMC8599354 DOI: 10.1007/s13318-021-00713-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/17/2021] [Indexed: 12/25/2022]
Abstract
Background and Objective One approach of therapeutic drug monitoring in the case of mycophenolic acid (MPA) is a limited sampling strategy (LSS), which allows the evaluation of the area under the concentration–time curve (AUC) based on few concentrations. The aim of this systematic review was to review the MPA LSSs and define the most frequent time points for MPA determination in patients with different indications for mycophenolate mofetil (MMF) administration. Methods The literature was comprehensively searched in July 2021 using PubMed, Scopus, and Medline databases. Original articles determining multiple linear regression (MLR)-based LSSs for MPA and its free form (fMPA) were included. Studies on enteric-coated mycophenolic sodium, previously established LSS, Bayesian estimator, and different than twice a day dosing were excluded. Data were analyzed separately for (1) adult renal transplant recipients, (2) adults with other than renal transplantation indication, and (3) for pediatric patients. Results A total of 27, 17, and 11 studies were found for groups 1, 2, and 3, respectively, and 126 MLR-based LSS formulae (n = 120 for MPA, n = 6 for fMPA) were included in the review. Three time-point equations were the most frequent. Four MPA LSSs: 2.8401 + 5.7435 × C0 + 0.2655 × C0.5 + 1.1546 × C1 + 2.8971 × C4 for adult renal transplant recipients, 1.783 + 1.248 × C1 + 0.888 × C2 + 8.027 × C4 for adults after islet transplantation, 0.10 + 11.15 × C0 + 0.42 × C1 + 2.80 × C2 for adults after heart transplantation, and 8.217 + 3.163 × C0 + 0.994 × C1 + 1.334 × C2 + 4.183 × C4 for pediatric renal transplant recipients, plus one fMPA LSS, 34.2 + 1.12 × C1 + 1.29 × C2 + 2.28 × C4 + 3.95 × C6 for adult liver transplant recipients, seemed to be the most promising and should be validated in independent patient groups before introduction into clinical practice. The LSSs for pediatric patients were few and not fully characterized. There were only a few fMPA LSSs although fMPA is a pharmacologically active form of the drug. Conclusions The review includes updated MPA LSSs, e.g., for different MPA formulations (suspension, dispersible tablets), generic form, and intravenous administration for adult and pediatric patients, and emphasizes the need of individual therapeutic approaches according to MMF indication. Five MLR-based MPA LSSs might be implemented into clinical practice after evaluation in independent groups of patients. Further studies are required, e.g., to establish fMPA LSS in pediatric patients.
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Affiliation(s)
- Joanna Sobiak
- Department of Physical Pharmacy and Pharmacokinetics, Poznan University of Medical Sciences, 6 Święcickiego Street, 60-781, Poznan, Poland.
| | - Matylda Resztak
- Department of Physical Pharmacy and Pharmacokinetics, Poznan University of Medical Sciences, 6 Święcickiego Street, 60-781, Poznan, Poland
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