A multicenter, open-label, pharmacokinetic/pharmacodynamic safety, and tolerability study of basiliximab (Simulect) in pediatric de novo renal transplant recipients

Rituximab as induction therapy in pediatric kidney transplantation: A single-center experience in four patients

BACKGROUND

The anti-CD20 rituximab is often used in the treatment of children with steroid-resistant nephrotic syndrome or EBV-induced post-transplant lymphoproliferative disorder. This single-center series reports the use of rituximab as induction therapy in pediatric kidney transplantation.

METHODS

Four children who received rituximab as induction therapy for kidney transplantation since 2016 were retrospectively analyzed. Clinical and laboratory data were extracted from medical records.

RESULTS

The patients (2 boys and 2 girls) were aged from 6.1 to 11.9 years and were treated with rituximab on the day of the transplantation procedure; all the transplants came from deceased donors. In all patients, rituximab was used because of positive EBV viral loads before kidney transplantation. Viral loads remained undetectable for the first 6 months after the transplantation procedure and remained below the 4.5 log threshold thereafter. After a median follow-up of 2.3 years, none of the patients displayed rejection or de novo donor-specific antibodies; the glomerular filtration rate remained above 70 ml/min/1.73 m² . No post-transplant lymphoproliferative disorder was observed.

CONCLUSION

The results suggest that rituximab can be used as induction therapy to prevent EBV replication and its complications in case of positive viral load prior to kidney transplantation.

Pediatric physiology in relation to the pharmacokinetics of monoclonal antibodies

INTRODUCTION

Dose design for pediatric trials with monoclonal antibodies (mAbs) is often extrapolated from the adult dose according to weight, age, or body surface area. While these methods account for the size differences between adults and children, they do not account for the maturation of processes that may play a key role in the pharmacokinetics and/or pharmacodynamics of mAbs. With the same weight-based dose, infants and young children typically receive lower plasma exposures when compared to adults. Areas covered: The mechanistic features of mAb distribution, elimination, and absorption are explored in detail and literature-based hypotheses are generated to describe their age-dependence. This knowledge can be incorporated into a physiologically based pharmacokinetic (PBPK) modeling approach to pediatric dose determination. Expert opinion: As data from pediatric clinical trials become increasingly available, we have the opportunity to reflect on the physiologic drivers of pharmacokinetics, safety, and efficacy in children with mathematical models. A modeling approach that accounts for the age-related features of mAb disposition can be used to derive first-in-pediatric doses, design optimal sampling schemes for children in clinical trials and even explore new pharmacokinetic end-points as predictors of safety and efficacy in children.

Effects of interleukin 2 receptor blockers on patient and graft survival in renal-transplanted children

Background:

Monoclonal antibodies block interleukin-2 receptors on alloantigen-reactive T-Lymphocytes and induce selective immunosuppression. It is postulated that induction therapy with these agents in pediatric transplantation may decrease acute rejection and improve graft survival with no significant side effect or increase in the incidence of viral infections.

Objectives:

The aim of this study was to examine the effects of interleukin 2 receptor blockers on patient and graft survival in renal-transplanted children.

Patients and Methods:

One hundred and eighty six children aged 7-13 years who received renal transplantation in university-affiliated hospital between 2003 and 2012 were enrolled in the study. All patients received prednisolone, cyclosporine and mycophenolate mofetil or azathioprine as basic immunosuppressive therapy. Patients were divided into two groups according to receiving induction therapy with IL2-receptor blockers. We investigated for acute rejection episodes, Cytomegalovirus (CMV) and BK virus infection and one and three year’s survival of the patients and the grafts

Results:

From 186 renal-transplanted children included in this study, 36 patients were in treated group (group 1) and 150 patients in control group (group 2). The mean age of the patients was 10.4 ± 2 years and 55.6% were males. In first six months of transplantation, eight patients in group one had one episode of acute rejection and no one had two episodes. Early acute rejection rate was 8.36 (22%). In the control group, 37 patients had one episode and three patients had two episodes of acute rejection (rejection rate 28.6%). Therefore, early acute rejection rates were lower in group one. Late acute rejection rates did not show any difference in group 1 and group 2 (27.7% vs. 27.3% respectively). There was lower prevalence of steroid-resistance rejection in group 1 patients (5.5%) compared with 6.6% in group 2, but it did not reach statistical significance. None of the patients in IL2-R blocker group died at one year follow-up (patient survival 100%). However, in control group, four (2.6%) patients died toward the end of first year (patient survival 97.4%). When patients in group 1 and group 2 were age and sex matched with equal number the difference was significant (P < 0.05).

Conclusions:

Induction therapy with IL2-R blockers reduced the rate of early acute rejection, but had no effect on late acute rejections. Patient and graft survival were better in treated group, but did not reach statistical significance. A longer period of follow-up may be required to discern a clear advantage for induction therapy with these agents.

Basiliximab: efficacy and safety evaluation in kidney transplantation

INTRODUCTION

Basiliximab is a chimeric monoclonal antibody directed against the alpha chain of interleukin-2 receptor (IL-2R). When administered intravenously at a dosage of 20 mg at the time of transplantation and 4 days later, basiliximab saturates the alpha chain of IL-2R for 4 weeks.

AREAS COVERED

This review evaluates the efficacy and safety of basiliximab in kidney transplantation. Randomized controlled trials showed that basiliximab can significantly reduce the incidence of acute rejection without increasing the risk of adverse events. When compared with other antibodies used for induction, basiliximab showed efficacy and safety profiles similar to daclizumab, another monoclonal antibody directed against the alpha chain of IL-2R. In comparison with rabbit anti-thymocyte globulins (rATG), basiliximab showed a similar efficacy. However, in patients at higher risk of rejection, rATG proved to be more effective. No serious safety problems related to basiliximab have been reported.

EXPERT OPINION

There is a solid evidence that basiliximab can significantly decrease the risk of acute rejection in kidney transplant recipients without increasing adverse events. This can allow decreased dosage or avoidance of glucocorticoids and reduced dosage of calcineurin inhibitors. On the basis of efficacy, tolerability, ease of administration, and cost effectiveness, basiliximab may be considered the drug of choice for the prophylaxis of acute rejection in standard renal transplant recipients.

Minimizing steroid use in pediatric kidney recipients

Outcomes of pediatric kidney transplantation have improved significantly over the years, such that the majority of graft recipients survive to become adolescents and adults. In this article, the findings of some of the important trials that shaped the current therapeutic landscape of immunosuppression will be reviewed. As an evolving landscape, novel strategies are continuously being sought to address the significant challenges in pediatric transplantation. Among these challenges is the development of immunosuppressive strategies that not only minimize the risk of allograft rejection but also allow normal growth and developmental patterns in children. To that end, the growing clinical evidence that indicates that the use of steroid-sparing regimens is effective will be reviewed. Finally, a brief description of the TWIST study will be provided. This large-scale comparative study has been designed specifically to assess the effect of early steroid withdrawal on growth in pediatric renal transplant recipients. An overview of the preliminary analysis of the eagerly anticipated results of this landmark trial will also be provided.

A randomized trial to assess the impact of early steroid withdrawal on growth in pediatric renal transplantation: the TWIST study

Minimizing steroid exposure in pediatric renal transplant recipients can improve linear growth and reduce metabolic disorders. This randomized multicenter study investigated the impact of early steroid withdrawal on mean change in height standard deviation score (SDS) and the safety and efficacy of two immunosuppressive regimens during the first 6 months after transplantation. Children received tacrolimus, MMF, two doses of daclizumab and steroids until day 4 (TAC/MMF/DAC, n=98) or tacrolimus, MMF and standard-dose steroids (TAC/MMF/STR, n=98). Mean change in height SDS was 0.16 +/- 0.32 with TAC/MMF/DAC and 0.03 +/- 0.32 with TAC/MMF/STR. The mean treatment group difference was 0.13 (p < 0.005 [95% CI 0.04-0.22]), 0.21 in prepubertal (p = 0.009 [95% CI 0.05-0.36]) and 0.05 in pubertal children (p = ns). Frequency of biopsy-proven acute rejection was 10.2%, TAC/MMF/DAC, and 7.1%, TAC/MMF/STR. Patient and graft survival and renal function were similar. Significantly greater reductions in total cholesterol and triglycerides but significantly higher incidences of infection and anemia were found with TAC/MMF/DAC (p < 0.05 all comparisons). Early steroid withdrawal significantly aided growth at 6 months more so in prepubertal than pubertal children. This was accompanied by significantly better lipid and glucose metabolism profiles without increases in graft rejection or loss.

Multicentre prospective randomised trial of tacrolimus, azathioprine and prednisolone with or without basiliximab: two-year follow-up data

A total of 192 children and adolescents undergoing renal transplantation were randomly chosen to receive tacrolimus, azathioprine and corticosteroids (TAS, n = 93) or tacrolimus, azathioprine, corticosteroids and two doses of basiliximab (TAS + B, n = 99). Six-month outcome data have previously been reported; this manuscript reports the 2-year data. Complete 2-year data were available on 164 (85.4%) of the original 192 patients. There was a single death in the TAS arm. Kaplan-Meier estimates of survival free of graft loss at 2 years were 94.9% in the TAS + B arm and 89.6% in the TAS arm [hazard ratio (HR) 0.52; 95% confidence interval (CI) 0.17 to 1.54, P = 0.23]. Estimates of survival free from rejection at 2 years were 75.2% in the TAS + B arm and 68.7% in the TAS arm (HR 0.81; 95% CI 0.46 to 1.40, P = 0.44). The mean estimated glomerular filtration rate (GFR) at 2 years, was 65.8 ml/min per 1.73 m(2) body surface area in the TAS arm and 66.7 ml/min per 1.73 m(2) in the TAS + B arm (P = 0.78). Blood pressure and cholesterol levels were similar in the two arms, and there was no evidence of a difference in the incidence of infection or malignancy. These data provide further evidence of a lack of benefit associated with the addition of basiliximab to a TAS regimen for European paediatric renal transplant recipients at low immunological risk.

Efficacy and safety of basiliximab in pediatric renal transplant patients receiving cyclosporine, mycophenolate mofetil, and steroids

BACKGROUND

Basiliximab, a monoclonal CD25 antibody has proofed effective in reducing acute rejection episodes in adults in various immunosuppressive regimens. The effect of basiliximab in the pediatric population is controversial.

METHODS

In a 12-month, double-blind, placebo-controlled trial, renal transplant patients aged 1 to 18 years were randomized to basiliximab or placebo with cyclosporine microemulsion, mycophenolate mofetil, and corticosteroids. The intent-to-treat population comprised 192 patients (100 basiliximab and 92 placebo).

RESULTS

The primary efficacy endpoint, time to first biopsy-proven acute rejection episode, or treatment failure by month 6, occurred in 16.7% of basiliximab-treated patients and 21.7% of placebo-treated patients (Kaplan-Meier estimates; hazard ratio 0.72, two-sided 90% confidence interval 0.416-1.26, n.s.). The rate and severity of subclinical rejections in protocol biopsies performed at 6 months posttransplant was higher in the basiliximab group (25.0%) than in the placebo group (11.7%). Patient and death-censored graft survival at 12 months was 97% and 99%, respectively, in the basiliximab cohort, and 100% and 99% among placebo-treated patients (n.s.). Renal function was similar in both treatment groups, and there were no significant between-treatment differences in the incidence of adverse events or infections.

CONCLUSIONS

Addition of basiliximab induction to a regimen of cyclosporine microemulsion, mycophenolate mofetil, and steroids resulted in a numerically lower but not significant incidence of biopsy-proven acute rejection versus placebo and excellent graft and patient survival at 1 year in pediatric renal transplant recipients. Whether this numerical difference is a true therapeutic benefit in view of the higher rate and severity of subclinical rejections in the basiliximab group in the protocol biopsy will be investigated in a long-term follow-up study.

Safety and pharmacokinetics of daclizumab in pediatric renal transplant recipients

This study examined the safety and pharmacokinetics/pharmacodynamics of daclizumab in combination with mycophenolate mofetil (or azathioprine), corticosteroids, and cyclosporine or tacrolimus, in 61 pediatric renal allograft recipients in three age groups: less than or equal to five yr (n = 18), 6-12 yr (n = 18), and 13-17 yr (n = 25). The dosing regimen was daclizumab 1.0 mg/kg before transplantation, followed by four biweekly doses. The pharmacokinetics of daclizumab were described using NONMEM software. Median (range) estimated trough daclizumab levels achieved on day 56 (before dose 5) were 3.88 microg/mL (2.48-8.78), 4.54 microg/mL (1.79-18.7), and 4.94 microg/mL (0.05-10.6) in the less than or equal to five yr (n = 15), 6-12 yr (n = 17), and 13-17 yr (n = 22) age groups, respectively. Steady-state median (range) daclizumab exposures were 2040 mg x h/mL (1585-3778), 2757 mg x h/mL (1873-3494) and 3297 mg x h/mL (1705-6453), respectively. Saturation of the IL-2R occurred rapidly and was maintained for greater than or equal to three months after transplantation. Daclizumab was generally well-tolerated with no acute allergic or anaphylactic reactions, deaths or malignancies during the study. The proportion of patients who developed acute rejection at six and 12 months was 8.5% and 16.7%, respectively. This study shows that adding daclizumab at 1 mg/kg to standard immunosuppressive therapy provides safe and effective IL-2R blockade.

Basiliximab induction therapy for live donor kidney transplantation: a long-term follow-up of prospective randomized controlled study

BACKGROUND/AIMS

The effect of basiliximab induction therapy on long-term patient and graft survival is not yet clear. We aimed to evaluate if there is any advantage of routine basiliximab induction on the long-term outcome of living related donor kidney transplantation.

METHODS

One hundred adult recipients with their first kidney allograft were randomized into two treatment groups, one group received basiliximab and the second served as a control. All patients received a maintenance triple immunosuppressive therapy (steroids, cyclosporine (CsA) micro-emulsion and azathioprine) and were followed up thoroughly for 7 years.

RESULTS

Basiliximab significantly reduced the proportion of patients who experienced acute rejection in the first year (18/50) when compared to the control group (31/50), and in 7 years (28/50) when compared to (37/50) in controls. The cumulative steroid dose used throughout the whole study period was significantly lower in the basiliximab group. The overall incidence of post-transplant complications was comparable among the two treatment groups. There was no significant difference in patient or graft survival; 7 years patient and graft survival were 92, 76% for basiliximab and 92, 80% for the control group, respectively.

CONCLUSION

Routine basiliximab induction significantly reduced the incidence of acute rejection without any noticeble beneficial effect on the long-term renal transplantation outcome.

Comparison of outcomes with low-dose anti-thymocyte globulin, basiliximab or no induction therapy in pediatric kidney transplant recipients: a retrospective study

It is unclear which induction therapy yields the best outcomes in pediatric kidney transplantation. Retrospective data of 88 children receiving a renal allograft between November 1996 and October 2003 were analyzed. Patients received ATGI (n = 12), BI (n = 29), or NAI (n = 47). The mean ATG dose was 5.1 +/- 2.1 mg/kg. At 12 months, graft survival rates were 91.7%, 100%, and 97.9% for ATGI, BI, and NAI groups, respectively. Acute rejection rates at 12 months were 0 (ATGI), 20.6% (BI), and 10.7% (NAI). The mean GFR for ATGI (42.4 +/- 25.9 mL/min) was lower than for BI (78.3 +/- 27.2 mL/min), and NAI (66 +/- 28.3 mL/min) at 12 months (p < 0.05). One ATGI patient developed CMV pneumonia but none developed post-transplant lymphoproliferative disorder. Although there was no renal allograft survival benefit with either ATGI or BI, relative to NAI, the absence of acute rejection and equivalent rates of viral infections in the higher-risk ATGI recipient group suggests that the treatment strategy is promising. A large prospective study is needed to better define the role of ATGI in pediatric kidney transplantation.

The role of basiliximab induction therapy in organ transplantation

Basiliximab is a chimeric monoclonal antibody that selectively binds to the alpha-subunit (CD25) of IL-2 receptors on the surface of activated T lymphocytes, and is a highly effective prophylaxis agent against rejection in organ transplant recipients. Its pharmacokinetic profile is characterized by a biphasic and slow clearance with long terminal half-life and a volume of distribution within the central compartment and outside the circulatory system. Basiliximab induction demonstrated an excellent safety profile, with no increase in the incidence of malignancy, infections or death. It has also been used effectively in high-risk recipients, steroid-sparing and steroid-minimization protocols, and in post-transplant patients with renal dysfunction who would benefit from delayed introduction of calcineurin inhibitors. Basiliximab induction therapy given at days 0 and 4 after transplantation appears to be safe and cost-effective for immunoprophylaxis in solid organ transplant recipients, specifically in kidney and liver transplantation, when given in conjunction with dual or triple immunosuppressive therapy.

A prospective, randomized, multicenter trial of tacrolimus-based therapy with or without basiliximab in pediatric renal transplantation

In a 6-month, multicenter, randomized, controlled, open-label, parallel-group trial, we investigated the efficacy and safety of adding basiliximab to a standard tacrolimus-based regimen in pediatric renal transplant recipients. Patients < 18 years received tacrolimus/azathioprine/steroids (TAS, n = 93) or tacrolimus/azathioprine/steroids/basiliximab (TAS + B, n = 99). Target tacrolimus levels were 10-20 ng/mL between days 0-21 and 5-15 ng/mL thereafter. Steroid dosing was identical in both groups. Basiliximab was administered at 10 mg (patients < 40 kg) or 20 mg (patients > or = 40 kg) within 4 h of reperfusion; the same dose was repeated on day 4. Biopsy-proven acute rejection rates were 20.4% (TAS) and 19.2% (TAS + B); steroid-resistant acute rejection rates were 3.2% and 3.0%, respectively. Patient survival was 100%; graft survival rates were 95% in both arms. The nature and incidence of adverse events were similar in both arms except toxic nephropathy and abdominal pain, which were significantly higher in the TAS + B arm (14.1% vs. 4.3%; p = 0.03 and 11.1% vs. 2.2%; p = 0.02; respectively). Median serum creatinine concentrations at 6 months were 86 micromol/L in the TAS and 91 micromol/L in the TAS + B arm; glomerular filtration rate was 79.4 and 77.6 (mL/min/1.73 m2), respectively. Adding basiliximab to a tacrolimus-based regimen is safe in pediatric patients, but does not improve clinical efficacy.

Pediatric renal transplantation: a single center experience over 14 years

Between 1989 and 2003, 100 transplants were performed in 96 patients at the pediatric nephrology unit of the Calvo Mackenna Children's Hospital. Mean age 10.9 +/- 3.9 yr (1-17.6), 30% from LD. Donors were younger than 5 yr in five patients and all recipients received an 'en bloc' graft. Original disease was hypo/dysplasia 27%, reflux nephropathy 22 and 17% chronic glomerulonephritis. The immunosuppressive protocol during the first period (n = 56, 1989-2000): Cyclosporine, steroids and azathioprine, and during the second period (n = 44, 2001-2003): FK, steroids, MMF and anti-CD25 antibody (mAbs). AR was reported in 22 patients, 11% in LD, 31% in DD (p < 0.01). The AR rate decreased from 40 to 8% after anti-CD25 monoclonal induction. Patient actuarial survival rate at 1, 3 and 5 yr was 100% for LD and 96% for DD. The overall actuarial graft survival at 1,3, and 5 yr was 96.7, 96.7 and 71% for LD and 89, 76 and 73% for DD donors. Graft survival rate improved from the first period (1989-2000) to the second period (2001-2003; p = 0.05). No difference in graft survival rate with HLA-A,B,DR matching was found. Graft survival rate was better when cold ischemia time was <24 h (p < 0.01). CMV infections increased from 19 to 40% when MMF and anti-CD25 Ab were introduced (p < 0.01). The height/age Z score at 1, 3 and 5 yr post-transplant was -2.2, -2.1, -2.2, respectively, for children older than 7 yr and -1.8, -1.9, -2.1 for those transplanted younger than 7 yr of age who were switched to alternate day steroids (p < 0.01). The cause of graft lost was: chronic rejection eight, non-adherence four, AR four and vascular thrombosis two. The cause of death in two patients was fungus septicemia and accelerated rejection. Pediatric renal transplantation can be performed in our group with acceptable morbidity, low mortality and graft survival rates similar to other reports in North America and Western Europe. Graft survival rate improved with newer immunosuppression and greater experience at the center. Management of non-adherence and chronic rejection remain the major challenges.

The effect of urinary protein excretion in post-renal transplant recurrent nephrotic syndrome on basiliximab pharmacokinetics and pharmacodynamics in a pediatric patient

A pharmacokinetic and pharmacodynamic study of Basiliximab therapy has not been reported in recurrent post-renal transplant nephrotic syndrome. We assessed the effect of urinary protein in a focal segmental glomerulosclerosis patient. We measured the serum concentrations of basiliximab as well as the rate of activated CD25-positive T lymphocytes at fixed intervals in nephrotic versus eight nonnephrotic pediatric post-renal transplant patients. A significant reduction in the antibody concentrations was observed in focal segmental glomerulosclerosis. The CD25 expression rate showed a similar trend to the pharmacokinetic data. We conclude that cases of massive urinary protein excretion need special care to maintain immunosuppression in renal transplant using Basiliximab.

Antibody induction therapy in renal transplant patients receiving calcineurin-inhibitor immunosuppressive regimens: a comparative review

Acute rejection during the first year post-transplant is a key predictor of graft survival after renal transplantation. Use of induction therapy with a lymphocyte-depleting agent or an interleukin-2 receptor (IL-2R) antagonist can provide effective protection against rejection in the first critical weeks and months post-transplant. Polyclonal lymphocyte-depleting antibodies are associated with a low incidence of rejection but evidence of their benefit in terms of graft survival is lacking. Thymoglobulin appears to offer superior graft outcomes compared with generic antithymocyte globulin (ATG). The most frequent adverse events are symptoms of cytokine release syndrome, leukopenia, thrombocytopenia, and tachycardia; data on whether polyclonal antibody use increases the risk of lymphoma are conflicting. Muromonab CD3 (OKT3), a monoclonal lymphocyte-depleting antibody, is efficacious but a high incidence of cytokine release syndrome and increased risk of post-transplant lymphoproliferative disease have limited its use. Following their recent introduction, the IL-2R antagonists basiliximab and daclizumab are now used widely, after randomized trials demonstrated that addition to calcineurin inhibitor-based therapy significantly reduced acute rejection by approximately 30-40%. Meta-analyses and registry analysis suggest that addition of an IL-2R antagonist may improve graft survival. The safety profile of IL-2R antagonists is indistinguishable from placebo, with no apparent difference in incidence of infection or post-transplant lymphoproliferative disease. IL-2R antagonists and polyclonal lymphocyte-depleting antibodies (with delayed cyclosporine) offer equivalent efficacy in standard-risk populations; in a trial of high-risk patients, acute rejection rate and graft outcomes were improved with Thymoglobulin. Tolerability is superior with IL-2R antagonists: cytokine release syndrome and hematologic disturbances (notably leukopenia) are significantly more frequent with polyclonal antibodies. Cytomegalovirus infection may also be more common with lymphocyte-depleting antibodies. Thus, in patients at high risk of graft loss, Thymoglobulin may be the preferred choice for induction therapy, while for all other patients, IL-2R antagonists should be considered first-line choice for induction therapy.

Anti-IL-2 receptor antibody vs. polyclonal anti-lymphocyte antibody as induction therapy in pediatric transplantation

Current concerns in pediatric transplantation focus on chronic rejection which commonly leads to graft loss, and on long-term maintenance immunosuppression toxicity. Acute rejection has been associated with the subsequent development of chronic rejection. Therefore, induction therapy may provide potential benefits by preventing early acute rejection episodes and allowing delayed administration of calcineurin inhibitors or steroid avoidance. This review of the literature showed that induction therapy can reduce early and recurrent acute rejection episodes after pediatric solid organ transplantation. Whether this might result in better long-term graft survival has still to be confirmed. However, induction therapy has beneficial effects in high-risk recipients and allows steroid avoidance or calcineurin inhibitor minimization. Because they are very well tolerated, anti-IL-2 receptor antibodies are increasingly preferred to rabbit-antithymocyte globulin, but the former have not yet been proven to be more effective or to have less late toxicity than polyclonal agents. Benefits in early outcome and no increase in adverse events lead to recommend the use of IL-2 receptor antagonists as induction therapy after pediatric organ transplantation.

Pediatric Renal Transplantation: 13 Years of Experience—Report From The Chilean Cooperative Multicenter Group

Between 1989 and 2002, 178 renal transplants were performed in 168 pediatric patients in Chile. The mean age was 10.9 +/- 3.7 years (range 1 to 17.9). End-state renal disease etiologies were: congenital renal hypoplasia/dysplasia, chronic glomerulonephritis, and reflux nephropathy. Seventy received a graft from a living donor (LD), and 108 from a cadaveric donor (CD). Only 9% received antibody induction. Acute rejection episodes were reported in 76 patients: 38% in LD recipients and 48% in CD recipients (P = NS). One-, 3-, and 5-year graft survivals were 88%, 84%, and 76%, respectively, for LD and 86%, 79%, and 68% for CD recipients. Actuarial graft survival was significantly better among those patients with serum creatinine < 1 mg/dL at 1 year posttransplant compared with those with creatinine > 1 mg/dL (P < .05). The graft survival rate has improved from the first period (1989 to 1996) to the second period (1997 to 2002); (P = .05). Patient survival rates at 1, 3, and 5 years were 98%, 98%, and 98%, respectively, for LD, and 95%, 94%, and 94% for CD. Global height/age Z-score decreased from -0.7 at birth to -1.5 when dialysis started, and to -2.4 at the time of transplantation. The Z-score height/age at 1, 3, and 5 years posttransplantation was -2.25, -2.24, and -2.5. No significant differences were observed in transplant outcomes comparing patients younger than 7 years with those older ones. In conclusion, pediatric renal transplant has been performed in Chile with acceptable morbidity. The patient and graft survivals are similar to the reported international experience. In the last period there was a significant improvement in graft survival.

Open-Label, Multicenter Study on the Safety, Tolerability, and Efficacy of Simulect in Pediatric Renal Transplant Recipients Receiving Triple Therapy With Cyclosporin, Mycophenolate, and Corticosteroids

INTRODUCTION

Basiliximab is a monoclonal antibody directed to the interleukin-2 receptor. Several studies have demonstrated both its efficacy and safety. Even with the use of polyclonal antibodies in renal pediatric transplant recipients, the local incidence of steroid-resistant rejections has been close to 10% of the total incidence of acute rejection episodes (AREs). An open, multicenter prospective study was performed to assess the safety tolerability, and efficacy of induction with basiliximab in renal pediatric transplant patients receiving cyclosporine, mycophenolate, and steroids.

MATERIALS AND METHODS

Eighteen patients (8 boys) of mean age 11.9 +/- 4.5 years and body weight 32 +/- 15 kg received cadaveric (n = 7) or living (n = 11) donor grafts. Simulect was administered on days 0 and 4. Efficacy was assessed by the incidence of biopsy-proven acute rejection (BPAR). Safety assessment consisted of a description of the adverse events (AEs).

RESULTS

Six BPAR (Banff I and II) occurred in 5, (27.7%) children all of which were steroid responsive. Creatinine levels at day 7 and months 3, 6, and 12 were 1.6 +/- 1.5 mg/dL, 1.0 +/- 0.4 mg/dL, 1.0 +/- 0.5 mg/dL, and 1.0 +/- 0.4 mg/dL, respectively. Schwartz calculation at 12 months was 71 +/- 15 mL/1.73 m2 AEs were hypertension (12), anemia (9), abdominal pain (8), metabolic acidosis (8), nausea (7), diarrhea (2), gingival hypertrophy (2), hirsutism (2), lymphocele (2), and infections (15). No deaths, graft losses, PTLDs, or malignancies were observed.

CONCLUSIONS

No steroid-resistant AREs, were observed in this pediatric group using basiliximab. The Schwartz calculation at 12 months was 71 +/- 15 mL/min/1.73 m2.

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.

Anti-interleukin-2 receptor antibodies for the prevention of rejection in pediatric renal transplant patients: current status

The anti-interleukin-2 receptor (anti-IL-2R) antibody therapy is an exciting approach to the prevention of acute rejection after renal allograft transplantation whereby immunosuppression is exerted by a selective and competitive inhibition of IL-2-induced T cell proliferation, a critical pathway of allorecognition. The anti-IL-2R antibodies specifically block the alpha-subunit of the IL-2R on activated T cells, and prevent T cell proliferation and activation of the effector arms of the immune system. The anti-IL-2R antibodies are used as induction therapy, immediately after renal transplantation, for prevention of acute cellular rejection in children and adults. During acute rejection, the IL-2Ralpha chain is no longer expressed on T cells; thus, the antibodies cannot be used to treat an existing acute rejection. Two anti-IL-2R monoclonal antibodies are currently in clinical use: daclizumab and basiliximab. In placebo-controlled phase III clinical trials in adults, daclizumab and basiliximab in combination with calcineurin inhibitor-based immunosuppression, significantly reduced the incidence of acute rejection and corticosteroid-resistant acute rejection without increasing the risk of infectious or malignant complications, and neither antibody was associated with the cytokine-release syndrome. Children who receive calcineurin inhibitors and corticosteroids for maintenance immunosuppression, as well as children who receive augmented immunosuppression to treat acute rejection, are at increased risk of growth impairment, hypertension, hyperlipidemia, lymphoproliferative disorders, diabetes mellitus, and cosmetic changes. In older children, the cosmetic adverse effects frequently reduce compliance with the treatment, and subsequently increase the risk of allograft loss. Being effective and well tolerated in children, the anti-IL-2R antibodies reduce the need for calcineurin inhibitors while maintaining the overall efficacy of the regimen; thus, the anti-IL-2R antibodies increase the safety margin (less toxicity, fewer adverse effects) of the baseline immunosuppression. Secondly, the anti-IL-2R antibodies decrease the need for corticosteroids and muromonab CD3 (OKT3) in children as a result of decreased incidence of acute rejection. The recommended pediatric dose of daclizumab is 1 mg/kg intravenously every 14 days for five doses, with the first dose administered within 24 hours pre-transplantation. This administration regimen maintains daclizumab levels necessary to completely saturate the IL-2Ralpha (5-10 microg/mL) in children for at least 12 weeks.The recommended pediatric dose of basiliximab for recipients <35 kg is 10 mg, and 20 mg for recipients > or =35 kg, intravenously on days 0 and 4 post-transplantation. This administration regimen maintains basiliximab levels necessary to completely saturate the IL-2Ralpha (>0.2 microg/mL) in children for at least 3 weeks.

Current status of kidney transplant: update 2003

Pediatric transplantation has seen remarkable advances over the past two decades with reduced morbidity and mortality, reduced rejection rates, and improved long-term patient and allograft survival. Infants currently have short-term patient and allograft survival rates better than any other age group; short-term allograft survival rates in CD recipients are equal to those in LD recipients. With decreased rejection, long-term allograft survival is improving dramatically. Transplantation allows for much reduced risks and improved metabolic status, growth and development, and more normal social interactions. The future of transplantation continues to be exciting, with opportunities for reduced immunosuppressive medications and their side effects, and the elusive goal of transplantation tolerance seems within reach.

Basiliximab

Basiliximab (Simulect), a chimeric (human/murine) monoclonal antibody, is indicated for the prevention of acute organ rejection in adult and paediatric renal transplant recipients in combination with other immunosuppressive agents. Basiliximab significantly reduced acute rejection compared with placebo in renal transplant recipients receiving dual- (cyclosporin microemulsion and corticosteroids) or triple-immunotherapy (azathioprine- or mycophenolate mofetil-based); graft and patient survival rates at 12 months were similar. Significantly more basiliximab than placebo recipients were free from the combined endpoint of death, graft loss or acute rejection 3 years, but not 5 years, after transplantation. The incidence of adverse events was similar in basiliximab and placebo recipients, with no increase in the incidence of infection, including cytomegalovirus (CMV) infection. Malignancies or post-transplant lymphoproliferative disorders after treatment with basiliximab were rare, with a similar incidence to that seen with placebo at 12 months or 5 years post-transplantation. Rare cases of hypersensitivity reactions to basiliximab have been reported. The efficacy of basiliximab was similar to that of equine antithymocyte globulin (ATG) and daclizumab, and similar to or greater than that of muromonab CD3. Basiliximab was as effective as rabbit antithymocyte globulin (RATG) in patients at relatively low risk of acute rejection, but less effective in high-risk patients. Numerically or significantly fewer patients receiving basiliximab experienced adverse events considered to be related to the study drug than ATG or RATG recipients. The incidence of infection, including CMV infection, was similar with basiliximab and ATG or RATG. Basiliximab plus baseline immunosuppression resulted in no significant differences in acute rejection rates compared with baseline immunosuppression with or without ATG or antilymphocyte globulin in retrospective analyses conducted for small numbers of paediatric patients. Limited data from paediatric renal transplant recipients suggest a similar tolerability profile to that in adults. Basiliximab appears to allow the withdrawal of corticosteroids or the use of corticosteroid-free or calcineurin inhibitor-sparing regimens in renal transplant recipients. Basiliximab did not increase the overall costs of therapy in pharmacoeconomic studies.

CONCLUSION

Basiliximab reduces acute rejection without increasing the incidence of adverse events, including infection and malignancy, in renal transplant recipients when combined with standard dual- or triple-immunotherapy. The overall incidence of death, graft loss or acute rejection was significantly reduced at 3 years; there was no significant difference for this endpoint 5 years after transplantation. Malignancy was not increased at 5 years. The overall efficacy, tolerability, ease of administration and cost effectiveness of basiliximab make it an attractive option for the prophylaxis of acute renal transplant rejection.

A rational dosing algorithm for basiliximab (Simulect) in pediatric renal transplantation based on pharmacokinetic-dynamic evaluations

BACKGROUND

The pharmacokinetics and immunodynamics of basiliximab were assessed in 39 pediatric de novo kidney allograft recipients to rationally chose a dose regimen for this age group.

METHODS

In study part 1, patients were given 12 mg/m(2) of basiliximab by bolus intravenous injection before surgery and on day 4. An interim pharmacokinetic evaluation supported a fixed-dose approach for study part 2 in which infants and children received two 10-mg doses and adolescents received two 20-mg doses. Blood samples were collected over a 12-week period for analysis of basiliximab and soluble interleukin-2 receptor concentrations, flow cytometry, and screening for anti-idiotype antibodies.

RESULTS

Basiliximab clearance in infants and children (n=25) was reduced by approximately half compared with adults from a previous study and was independent of age (1-11 years), weight (9-37 kg), and body surface area (0.44-1.20 m(2) ). Clearance in adolescents (12-16 years, n=14) approached or reached adult values. CD25-saturating basiliximab concentrations were maintained for 31+/-12 days in study part 1 with mg/m(2) dosing and for 36+/-14 days in study part 2 based on the fixed-dose regimen ( P=0.31). A single patient experienced a rejection episode during CD25 saturation. The duration of CD25 saturation in patients who experienced a rejection episode after desaturation did not differ from those who remained rejection-free for the full 6-month period: 34+/-6 days (n=6) vs. 35+/-14 days (n=33 patients); P=0.74. Anti-idiotype antibodies were detected in two patients; however, this did not influence the clearance of basiliximab or the duration of CD25 saturation.

CONCLUSIONS

To achieve similar basiliximab exposure as is efficacious in adults, pediatric patients <35 kg should receive two 10-mg doses and those > or =35 kg should receive two 20-mg doses of basiliximab by intravenous infusion or bolus injection. The first dose is given before surgery and the second on day 4 after transplantation.