Cyclosporine A for the treatment of refractory nephrotic syndrome with renal dysfunction

Development of a Population Pharmacokinetic Model for Cyclosporine from Therapeutic Drug Monitoring Data

Aim

To develop a population pharmacokinetic model for Uruguayan patients under treatment with cyclosporine (CsA) that can be applied to TDM. Patients and Methods. A total of 53 patients under treatment with CsA were included. 37 patients with at least one pharmacokinetic profile described with four samples were considered for model building, while the remaining 16 were considered for the assessments of predictive performances. Pharmacokinetic parameter estimation was performed using a nonlinear mixed effect modelling implemented in the Monolix® software (version 2019R1, Lixoft, France); meanwhile, simulations were performed in R v.3.6.0 with the mlxR package.

Results

A two-compartment model with a first-order disposition model including lag time was used as a structural model. The final model was internally validated using prediction corrected visual predictive check (pcVPC) and other graphical diagnostics. A total of 621 CsA steady-state concentrations were analyzed for model development. Population estimates for the absorption constant (ka) and lag time were 0.523 h⁻¹ and 0.512 h, respectively; apparent clearance (CL/F) was 30.3 L/h (relative standard error [RSE] ± 8.25%) with an interindividual variability of 39.8% and interoccasion variability of 38.0%; meanwhile, apparent clearance of distribution (Q/F) was 17.0 L/h (RSE ± 12.1%) with and interindividual variability of 53.2%. The covariate analysis identified creatinine clearance (ClCrea) as an individual factor influencing the Cl of CsA. The predictive capacity of the population model was demonstrated to be effective since predictions made for new patients were accurate for C1 and C2 (MPPEs below 50%). Bayesian forecasting improved significantly in the second and third occasions.

Conclusion

A population pharmacokinetic model was developed to reasonably estimate the individual cyclosporine clearance for patients. Hence, it can be utilized to individualize CsA doses for prompt and adequate achievement of target blood concentrations of CsA.

Tacrolimus improves proteinuria remission in adults with cyclosporine A-resistant or -dependent minimal change disease

AIMS

Cyclosporin A (CsA) is considered as an effective treatment option for steroid-resistant or-dependent patients with adult-onset minimal change disease (MCD). However, CsA resistance or dependence is also observed in these patients. Tacrolimus (TAC) is a calcineurin inhibitor that is potent in cytokine suppression. The authors aim to evaluate the efficacy and safety of TAC therapy in CsA-resistant and-dependent adult-onset MCD patients.

METHODS

Patients with adult-onset MCD were enrolled in our department from 2008 to 2012. All patients were demonstrated to be resistant to or dependent on CsA therapy. Prednisone (0.5 mg/kg per day) combined with TAC (0.05-0.1 mg/kg per day) were prescribed to these patients for at least 6 months. The primary outcome was complete or partial remission of proteinuria. Secondary outcomes included time required for complete or partial remission, adverse events, number of relapses, and TAC dosages.

RESULTS

A total of 11 MCD patients were enrolled in this observational study. The numbers of patients who presented with resistance to or dependence on CsA were 7 and 4, respectively. The total remission rate was 90.9% (10/11) with the complete remission rate 72.7% (8/11). Most remission patients achieved remission during the first 2 months of TAC therapy. Patients who presented with dependence on CsA had achieved complete remission with TAC therapy, while outcomes for CsA-resistant patients were four complete remissions, two partial remissions and one resistance. The adverse events were observed in this study included infection, diarrhoea, and worsened hypertension. Five patients who had remission experienced relapse.

CONCLUSIONS

Tacrolimus improves proteinuria remission in adults with CsA-resistant or -dependent MCD.

Treatment effect of cyclosporine A in patients with painful bladder syndrome/interstitial cystitis: A systematic review

Cyclosporine A (CyA) is emerging as a potential therapeutic strategy for painful bladder syndrome/interstitial cystitis (PBS/IC), which is currently an incurable disease. The purpose of this systematic review was to evaluate the treatment effects of CyA in PBS/IC. Electronic and manual retrieval procedures were carried out to identify eligible references for the systematic review. The entire contents of the included articles were assessed, from study design to reported results. Eight studies, comprising three randomized controlled trials (RCTs), four prospective studies and one retrospective cohort study, were included, involving a total of 298 subjects. Meta-analysis was not implemented due to heterogeneity of the manner of reporting the outcome parameters. All studies reported an improvement in symptoms following treatment with CyA. The results of the three RCTs implied that the treatment effects of CyA were better than those of pentosan polysulfate sodium. Some adverse events, for example, elevation of serum creatinine levels and an increase in blood pressure, were noted in five studies. In conclusion, the evidence from the studies implied that treatment of CyA can result in a long-term benefit in patients of PBS/IC; however, further evidence is required to verify this.