Evidence-based immunosuppression after pediatric renal transplantation—A dream?

A time-to-event model for acute rejections in paediatric renal transplant recipients treated with ciclosporin A

AIMS

Ciclosporin A (CsA) dosing in immunosuppression after paediatric kidney transplantation remains challenging, and appropriate target CsA exposures (AUCs) are controversial. This study aimed to develop a time-to-first-acute rejection (AR) model and to explore predictive factors for therapy outcome.

METHODS

Patient records at the Children's Hospital in Helsinki, Finland, were analysed. A parametric survival model in NONMEM was used to describe the time to first AR. The influences of AUC and other covariates were explored using stepwise covariate modelling, bootstrap-stepwise covariate modelling and cross-validated stepwise covariate modelling. The clinical relevance of the effects was assessed with the time at which 90% of the patients were AR free (t90).

RESULTS

Data from 87 patients (0.7-19.8 years old, 54 experiencing an AR) were analysed. The baseline hazard was described with a function changing in steps over time. No statistically significant covariate effects were identified, a finding substantiated by all methods used. Thus, within the observed AUC range (90% interval 1.13-8.40 h mg l⁻¹), a rise in AUC was not found to increase protection from AR. Dialysis time, sex and baseline weight were potential covariates, but the predicted clinical relevance of their effects was low. For the strongest covariate, dialysis time, median t90 was 5.8 days (90% confidence interval 5.1-6.8) for long dialysis times (90th percentile) and 7.4 days (6.4-11.7) for short dialysis times (10th percentile).

CONCLUSIONS

A survival model with discrete time-varying hazards described the data. Within the observed range, AUC was not identified as a covariate. This feedback on clinical practice may help to avoid unnecessarily high CsA dosing in children.

Pediatric renal transplantation in the jordanian population: the clinical outcome measures during long-term follow-up period

INTRODUCTION

Recently, many international studies have suggested that pediatric patients from diverse ethnic origins confront unique challenges for transplantation. Data concerning the efficacy and safety of transplantation for various pediatric renal transplant populations remains limited and are often confounded by immunosuppressive protocols. In one study, we aimed to evaluate the short- and long-term outcomes of renal transplants in Jordanian children in comparison with groups of different nationalities.

METHODS

We retrospectively retrieved data for 34 Jordanian children who received kidney transplants from living donors between January 2003 and January 2009. Subsequently, we continued to follow-up with these selected patients at scheduled clinic visits to prospectively collect long-term data for a period of approximately 22 months±15 months.

RESULTS

The patients included in this study ranged between 4 years and 19 years of age. The male/female ratio was 0.79. Glumerulonephritis (35.3%) was the most common cause of end-stage renal disease in the sample of this study; 23.5% had received a preemptive transplant. All patients also received triple immunosuppressive therapy, consisting of tacrolimus (TAC), prednisolone, and mycophenolate mofetil (n=26) or azathioprine (n=8). Furthermore, the rate of acute rejection episodes was lower in the sample of this study than the average rate of many previous studies. The patients' survival rate at 1 year, 2 years and 3 years posttransplant was nearly 100%. The corresponding graft survivals were 97.1%, 94.12% and 91.2% respectively. Beyond three years, one female patient died postgraft loss. This graft loss was mainly attributed to recurrent glomerulonephritis. Strikingly, the prevalence of posttransplant diabetes (PTD) and hypertension was higher than reported international figures. Other adverse events, such as infections, were manageable.

CONCLUSION

The average result of pediatric renal transplantation in Jordan is more successful than the average results of this procedure in many developed countries, especially in terms of early graft function, acute rejection episodes as well as long-term patient and graft survivals. However, additional studies are needed to better characterize pharmacokinetic of TAC and to fully understand those factors that lead to an increased probability of developing conditions like PTD and hypertension.

Four-year data after pediatric renal transplantation: a randomized trial of tacrolimus vs. cyclosporin microemulsion

This study was undertaken to compare the efficacy and safety of tacrolimus (Tac) with cyclosporin microemulsion (CyA) in pediatric renal recipients. A 6-month, randomized, prospective, open, parallel group study with an open extension phase was conducted in 18 centers from nine European countries. In total, 196 pediatric patients (<18 yr) were randomly assigned (1:1) to receive either Tac (n = 103) or CyA (n = 93) administered concomitantly with azathioprine and corticosteroids. The primary endpoint was incidence and time to first acute rejection (intent-to-treat). Baseline characteristics were comparable between treatment groups. Excluding deceased patients (n = 9) and patients lost to follow-up (n = 31, mostly transferred to adult care), 95% of 2-yr data (159 of 167 possible patients), 87% of 3-yr data (142 of 163) and 73% of 4-yr data (114 of 156) were retrieved. At 1 yr Tac therapy resulted in a significantly lower incidence of acute rejection (36.9%) compared with CyA (59.1%, p = 0.003). The incidence of corticosteroid-resistant rejection was also significantly lower with Tac (7.8% vs. 25.8%, p = 0.001). At 4 yr, patient survival was similar (94% vs. 92%, p = 0.86) but graft survival significantly favored Tac (86% vs. 69%; p = 0.025, log-rank test), respectively. At 1 yr, the mean glomerular filtration rate (GFR) (Schwartz formula, ml/min/1.73 m(2)) was 64.9 +/- 20.7 (n = 84) vs. 57.8 +/- 21.9 (n = 77, p = 0.0355), at 2 yr 64.9 +/- 19.8 (n = 71) vs. 51.7 +/- 20.3 (n = 66, p = 0.0002), at 3 yr 66.7 +/- 26.4 (n = 81) vs. 53.0 +/- 23.3 (n = 55, p = 0.0022), and at 4 yr 71.5 +/- 22.9 (n = 51) vs. 53.0 +/- 21.6 (n = 44, p = 0.0001) for Tac vs. CyA, respectively. Cholesterol remained significantly higher with CyA throughout follow-up. Three patients in each arm developed post-transplant lymphoproliferative disease. Incidence of insulin-dependent diabetes mellitus was not different. Tac was significantly more effective than CyA in preventing acute rejection in pediatric renal recipients. Renal function and graft survival were also superior with Tac. Glomerular filtration rate appears to be an useful surrogate marker for long-term outcome.

Mycophenolate mofetil in pediatric renal transplantation: non-induction vs. induction with basiliximab

North American Pediatric Renal Transplant Cooperative Study (NAPRTCS) reports have shown anti-T cell antibody, OKT3, to be deleterious in pediatric renal transplant recipients treated with mycophenolate mofetil (MMF). Unlike OKT3, basiliximab is a chimeric monoclonal antibody to the alpha subunit of the interleukin-2 receptor on activated T-lymphocytes. We sought to examine the outcome of MMF with or without basiliximab induction therapy in pediatric renal transplantation. Between January 1998, and June 2001, 49 pediatric renal transplants were performed at our center and 41 met the criteria for this study. We retrospectively analyzed the records of 25 patients who received MMF, Prednisone, CSA or TAC, alone (group I) and 16 patients who received MMF, CSA or TAC, and Prednisone in combination with basiliximab (group II). The two groups were similar with respect to recipient or donor age, gender, ethnicity, donor source (LD vs. CAD), cold ischemia time, and primary diagnosis. The basiliximab group had a shorter follow up period because of its more recent addition to our pediatric immunosuppression protocol, 12.9 +/- 5.9 months vs. 35.5 +/- 7.2 months for group I (p < 0.0001). At 6 months, the acute rejection rate was 16% (group I) compared with 25% (group II) (p = 0.689). The patient and graft survival at 6 and 12 months were 100% respectively for both groups. Basiliximab was well tolerated without significant adverse events. At 6 months, there was no significant difference between the groups in the incidence of urinary tract infection or cytomegalovirus infection. These data suggest that in the short-term, MMF with or without basiliximab induction therapy appears to yield excellent and statistically similar outcomes. However, further controlled studies are necessary to verify these findings as well as to define the role of basiliximab in MMF-treated pediatric renal transplant recipients.