Pharmacokinetic Analysis of Mycophenolate Mofetil and Enteric-Coated Mycophenolate Sodium in Calcineurin Inhibitor–Free Renal Transplant Recipients

Enteric-coated Mycophenolate Sodium therApy versus cyclophosphamide for induction of Remission in Microscopic PolyAngiitis (EMSAR-MPA trial): study protocol for a randomised controlled trial

INTRODUCTION

Several studies have demonstrated that mycophenolate mofetil (MMF) may be an excellent alternative to cyclophosphamide (CYC) or rituximab for the induction of remission in non-life-threatening anti-neutrophil cytoplasmic antibodies associated vasculitis because of its strong immunosuppressive potency and low toxicity profile. Enteric-coated mycophenolate sodium (EC-MPS) was introduced to reduce gastrointestinal adverse reactions of MMF. This study will evaluate the efficacy and safety of EC-MPS combined with glucocorticoid in patients with active and non-life-threatening microscopic polyangiitis (MPA).

METHODS AND ANALYSIS

This study is a multicentre, open-label, randomised controlled, non-inferiority trial. A total of 110 patients with active and non-life-threatening MPA from 11 hospitals in Shanxi Province of China will be recruited and randomised in a 1:1 ratio to receive either EC-MPS or CYC. All patients will receive the same glucocorticoid plan. We will compare oral EC-MPS (720-1440 mg/day) with intravenous pulsed CYC (7.5-15 mg/kg) administered for 3-6 months. All patients will be switched from their assigned treatment (EC-MPS or CYC) to oral azathioprine (2 mg/kg/day) after remission has been achieved, between 3 and 6 months. Azathioprine will be continued until the study ends at 18 months. The primary end point of efficacy is the remission rate at 6 months. Follow-up will continue for 18 months in order to detect an influence of induction regimen on subsequent relapse rates.

ETHICS AND DISSEMINATION

This study has received approval from the Ethics Committee of the Second Hospital of Shanxi Medical University (2022YX-026). All participants are required to provide written informed consent and no study-related procedures will be performed until consent is obtained. The results of this trial will be published in peer-reviewed journals and presented at conferences.

TRIAL REGISTRATION NUMBER

ChiCTR2200063823.

Population Pharmacokinetics of Enteric-Coated Mycophenolate Sodium in Children after Renal Transplantation and Initial Dosage Recommendation Based on Body Surface Area

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, AUC_0-12h 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.

Mycophenolate Mofetil (CellCept®) in Combination With Low Dose Prednisolone in Moderate to Severe Graves' Orbitopathy

Although corticosteroids are currently the first-choice drug for thyroid eye disease (TED), in 20–30% of cases, patients show poor or non-existent responses, and when the drug is withdrawn, 10–20% of patients relapse. Thus, in this study, we aimed to investigate the efficacy of the combined use of mycophenolate mofetil (CellCept®) and low dose oral prednisolone in patients with moderate to severe Graves' orbitopathy (GO). For the first time, we investigated the relationship between TED-related parameters and proptosis reduction. In a prospective, non-randomized, interventional case series, 242 patients with moderate-to-severe GO were, assigned to receive oral prednisolone (5 mg/ d) and mycophenolate mofetil (CellCept®) (one 500 mg tablet twice per day according to the therapeutic response). The patients were monitored regularly during the 3rd, 6th, 12th, and 18th month of treatment. The main outcome measures were the clinical activity score (CAS), intraocular pressure (IOP), diplopia, proptosis and visual acuity. We also assessed the relationship between the main outcomes with proptosis changes and time to improvement (months). Adverse effects were recorded during each visit. The clinical response rate increased from 67.7% on the third month to 89.2% on the sixth month, and 94.2% on the 12th month. This therapeutic response continued until the 18th month of follow-up. The CAS responses [disease inactivation (CAS <3)] improved during our study: 70.6% on the third month, 90.0% on the sixth month, and 92.5% at 12th month. These conditions continued until the 18th month of follow-up. Proptosis improvement was 52% on the third month, 71% on the sixth month, 83% on the 12th month, and 87.1% on the 18th month. Changes in IOP and visual acuity were not significant (P = 0.568 and 0.668, respectively). The patient showed significant improvement in the Gorman score. A Shorter duration of treatment was seen in patients with earlier onset of intervention, younger age, and lack of all extraocular muscle (EOM) enlargement on computed tomography (CT) scan (p < 0.05). In addition, a better response (more reduction) in proptosis was related to: younger age at disease, earlier treatment intervention (less interval from the time the diagnosis of moderate-to-severe GO was made until medication initiation), shorter treatment time (less time to improvement), less IOP, lack of EOM enlargement on CT scan, and lack of diplopia (P < 0.05). Adverse events occurred in six patients. Findings show that mycophenolate mofetil (CellCept®) plus low-dose prednisolone can be introduced as a new optimal dosing regimen in GO due to its better effect on chronic complications such as proptosis and diplopia.

Diarrhea in the pediatric solid organ transplantation recipient: A multidisciplinary approach to diagnosis and management

Diarrhea in the pediatric solid organ transplantation (SOT) recipient is a frequent complaint that is associated with significant morbidity and impaired quality of life. There are limited published data regarding the specific epidemiology, diagnostic evaluation, and treatment of diarrhea after SOT in children. Pediatric SOT recipients have an increased risk of developing diarrhea because of a generalized immunosuppressed state, epidemiologic exposures, and polypharmacy. There is a need to standardize the diagnostic evaluation of diarrhea in children after SOT to facilitate an accurate diagnosis and timely treatment. Herein, we review the available published data and propose a systematic, stepwise approach to the evaluation of diarrhea in this high-risk population, focusing on timely diagnosis of both infectious and non-infectious causes, in order to provide focused management. Prospective studies are needed to better assess the true prevalence, risk factors for, etiologies, and complications of diarrhea in pediatric SOT patients that will guide optimal management. Development of effective vaccines and antiviral therapies for enteric viruses may also contribute to improved outcomes.

Application of Contrast-Enhanced Sonography on the Diagnosis of Acute and Chronic Rejection After Renal Transplantation

To test the reliability of CEUS on the diagnosis of acute (AR) or chronic rejection (CR) after renal transplantation, patients who received renal transplantation in our center from January 2011 and December 2015 were retrospectively included in the current study. All the included patients underwent contrast-enhanced ultrasonography tests. Two regions of interests were chosen to carry out time-intensity curves (TICs). The main indexes include time indexes, intensity indexes, and difference indexes. Separation of TIC1 and TIC2 was evaluated by the authors. Results revealed that time to peak 1 (TTP-1), TTP-2, absolute time to peak 1 (ATTP-1), and ATTP-2 in the CR group were significantly later than those in the graft function stable group. Peak intensity 2 is smaller in the AR group than that in the GFS group, velocity of intensity ascending 2 is slower in the CR group than that in the GFS group, terminal intensity 1 (TI-1) and TI-2 are lower in the CR group than those in the GFS group, and Vd-1 is faster in the CR group than that in the GFS group (P < 0.05). Those results indicated that contrast-enhanced ultrasonography test can satisfactorily reflect the microcirculation of transplanted kidney and can be used to assist in the early diagnosis of graft rejection.