Effective treatment of anemia in pediatric kidney transplant recipients with methoxy polyethylene glycol-epoetin beta

Clinical Experience of a Long-acting Pegylated Erythropoietin-Stimulating Agent in Pediatric Chronic Kidney Disease

OBJECTIVE

Management of anemia of chronic kidney disease (CKD) often includes subcutaneous or intravenous administration of erythropoietin-stimulating agents (ESAs). Mircera, a pegylated continuous erythropoietin receptor agonist, has a longer duration of action and requires less frequent administration than other ESAs. Pediatric experience with Mircera is limited. We retrospectively reviewed our long-term experience of Mircera in a national pediatric nephrology center.

METHODS

Patients were identified via an electronic patient record database. Data collected included demographics (sex, age, etiology of CKD, CKD stage, dialysis modality), dosing information, and laboratory data-hemoglobin (Hb), parathormone (PTH), ferritin, hematinics prior to commencing Mircera and all subsequent values associated with dose adjustments.

RESULTS

Seventy-seven patients aged 2 to 18 years, with CKD stages 2 to 5T had received at least 1 dose of Mircera, with 75 patients having sufficient data and a total of 1473 doses. No patients discontinued Mircera owing to adverse effects. One patient experienced a potential severe adverse drug reaction. Mircera was effective in improving or maintaining Hb ≥10.0 g/dL in most (58/75, 77.3%) patients. The median dose to achieve Hb ≥10.0 g/dL was 2.1 µg/kg/4 wk. Most doses (1039, 71.5%) were administered 4-weekly. The doses (161, 11.1%) that were administered 6-weekly remained efficacious. Thirty-two patients started Mircera with Hb <10.0 g/dL; 26 (81%) achieved Hb ≥10.0 g/dL within a median time of 4 months. Mircera was less effective if given every 8 weeks, or in the presence of hyperparathyroidism or hyperferritinemia.

CONCLUSION

Mircera appears safe and effective in pediatric patients with CKD.

Anemia after kidney transplantation

Anemia is a frequent complication in pediatric kidney transplant recipients (KTR) with a variable reported prevalence estimated between 20 and 80% depending on how defined. Causes of and risk factors for post-transplantation anemia (PTA) are multifactorial with iron deficiency being the primary cause of early PTA (within the first 6 months after transplantation) and impaired glomerular filtration rate (GFR) commonly responsible for late PTA (after 6 months). Medications, viral infections, chronic inflammation, and comorbidities also play a role. PTA has relevant long-term consequences and is a potential risk factor for allograft dysfunction, cardiovascular morbidity, and mortality. Thus, an anemia evaluation, approximately 3 months post-transplantation, is recommended in order to start early treatment and improve prognosis. Iron status, vitamin B12, folate, markers of hemolysis, and viral PCR should be checked, and medications, in particular combinations of medications, should be carefully evaluated. PTA treatment may be challenging and should be directed to the underlying causes. Iron supplementation and erythropoietin therapy, not extensively used in KTR, may be indicated. Every effort should be made to avoid blood transfusions in the pre-transplant period to avoid allosensitization. Anemia should be corrected to prepare candidates for kidney transplantation in order to reduce the need for perioperative blood transfusions as well.

Subcutaneous C.E.R.A. for the Maintenance Treatment of Anemia in Pediatric Patients With CKD: A Phase 2, Open-Label, Single-Arm, Multicenter Study

RATIONALE & OBJECTIVE

The optimum starting dose of intravenous continuous erythropoietin receptor activator (C.E.R.A.) has been previously determined; this study ascertains the optimum starting dose of subcutaneous C.E.R.A. administration in pediatric patients.

STUDY DESIGN

Phase 2, open-label, single-arm, multicenter study.

SETTING & PARTICIPANTS

Patients aged 3 months to 17 years with renal anemia and chronic kidney disease (CKD; including those treated with maintenance dialysis and those not treated with dialysis) who were receiving maintenance treatment with erythropoiesis-stimulating agents (ESAs).

INTERVENTION

Subcutaneous C.E.R.A. administration every 4 weeks (starting dose was based on defined conversion factors).

OUTCOME

The primary outcome was the change in hemoglobin concentration between the baseline and evaluation period for each patient. Secondary efficacy measures and safety were also evaluated.

RESULTS

Forty patients aged 0.4-17.7 years were enrolled. The study achieved its primary outcome: the mean change in hemoglobin concentration was an increase of 0.48g/dL; the 95% confidence interval (0.15-0.82) and standard deviation (±1.03) were within the prespecified boundaries (-1 to 1g/dL and<1.5g/dL, respectively). Mean hemoglobin concentrations were maintained within the target 10-12g/dL range in 24 of 38 patients and within±1g/dL of the baseline in 19 of 38 patients, and the median C.E.R.A. subcutaneous dose decreased over time. Efficacy in key subgroups (age group, dialysis type, prior ESA treatment) was consistent with the primary outcome. Thirty-eight patients completed the core period; 25 chose to enter the safety extension period. Safety was consistent with prior studies, with no new signals.

LIMITATIONS

Single-arm and open-label study; small sample size.

CONCLUSIONS

Pediatric patients with anemia secondary to CKD who were on, or not on, dialysis could be safely and effectively switched from maintenance ESAs to subcutaneous C.E.R.A. administered every 4 weeks, using defined dose-conversion factors to determine the optimum starting dose.

FUNDING

F. Hoffmann-La Roche Ltd.

TRIAL REGISTRATION

The SKIPPER trial registered at ClinicalTrials.gov with study number NCT03552393.

Use of erythropoiesis-stimulating agents in children with chronic kidney disease: a systematic review

Background

Erythropoiesis-stimulating agents (ESAs) revolutionized the management of anaemia in chronic kidney disease (CKD) when introduced in the late 1980s. A range of ESA types, preparations and administration modalities now exist, with newer agents requiring less frequent administration. Although systematic reviews and meta-analyses have been published in adults, no systematic review has been conducted investigating ESAs in children.

Methods

The Preferred Reporting Items for Systematic Reviews and Meta-analyses statement for the conduct of systematic reviews was used. All available literature on outcomes relating to ESAs in children with CKD was sought. A search of the MEDLINE, CINAHL and Embase databases was conducted by two independent reviewers. Inclusion criteria were published trials in English, children with chronic and end-stage kidney disease and use of any ESA studied against any outcome measure. An assessment of risk of bias was carried out in all included randomized trials using the criteria from the Cochrane Handbook for Systematic Reviews of Interventions. Two tables were used for data extraction for randomized and observational studies. Study type, participants, inclusion criteria, case characteristics, follow-up duration, ESA type and dosage, interventions and outcomes were extracted by one author.

Results

Of 965 identified articles, 58 were included covering 54 cohorts. Six were randomized trials and 48 were observational studies. A total of 38 studies assessed the efficacy of recombinant human erythropoietin (rHuEPO), 11 of darbepoetin alpha (DA) and 3 of continuous erythropoietin receptor activator (CERA), with 6 studies appraising secondary outcome measures exclusively. Recruitment to studies was a consistent challenge. The most common adverse effect was hypertension, although confounding effects often limited direct correlation. Two large cohort studies demonstrated a greater hazard of death independently associated with high ESA dose. Secondary outcome measures included quality of life measures, growth and nutrition, exercise capacity, injection site pain, cardiovascular function, intelligent quotient, evoked potentials and platelet function.

Conclusions

All ESA preparations and modes of administration were efficacious, with evidence of harm at higher doses. Evidence supports individualizing treatments, with strong consideration given to alternate treatments in patients who appear resistant to ESA therapy. Further research should focus on randomized trials comparing the efficacy of different preparations, treatment options in apparently ESA-resistant cohorts and clarification of meaningful secondary outcomes to consolidate patient-relevant indices.

Efficacy and Long-Term Safety of C.E.R.A. Maintenance in Pediatric Hemodialysis Patients with Anemia of CKD

BACKGROUND AND OBJECTIVES

The study was conducted to identify a conversion factor for switching from previous erythropoiesis-stimulating agents (ESAs) to continuous erythropoietin receptor activator-methoxy polyethylene glycol-epoetin beta (C.E.R.A.) and to document the efficacy and long-term safety of C.E.R.A. in pediatric patients with anemia of CKD undergoing hemodialysis.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

In this open-label, multicenter study, patients aged 6-17 years, with stable chronic anemia of CKD, undergoing hemodialysis received C.E.R.A. every 4 weeks, at a starting dose determined by previous weekly epoetin alfa/beta or darbepoetin dosing. After a 16-week dose-titration and a 4-week evaluation period, patients with stable hemoglobin could enter a 1-year optional safety extension.

RESULTS

A total of 64 patients were enrolled. A conversion factor (4 µg every 4 weeks for each weekly dose of 125 IU epoetin alfa/beta or 0.55 µg darbepoetin) was identified that allowed patients to maintain hemoglobin within target levels on switching to C.E.R.A. from another ESA. Using this conversion factor, the adjusted mean change in hemoglobin from baseline to evaluation was -0.09 g/dl (95% confidence interval, -0.45 to 0.26); 81% of patients maintained hemoglobin within 10.0-12.0 g/dl and 75% maintained hemoglobin within 1.0 g/dl of baseline. Results were consistent across age groups (6-11 and 12-17 years) and previous ESA. Thirty-seven patients entered the safety extension period and 17 completed 73 weeks of treatment. Most withdrawals were for kidney transplantation. A total of 70% of patients had hemoglobin within 10.0-12.0 g/dl at last observation, and 62% were within ±1.0 g/dl of baseline. Safety was similar to studies in adult patients, with no new signal detected.

CONCLUSIONS

Using a defined conversion factor, 4-weekly C.E.R.A. was efficacious in maintaining hemoglobin levels in pediatric patients with stable anemia of CKD undergoing hemodialysis, switching from maintenance treatment with epoetin alfa/beta or darbepoetin. Safety was consistent with the known C.E.R.A. safety profile in adults.

Methoxy polyethylene glycol-epoetin beta for the treatment of anemia associated with chronic renal failure

Since more than two decades erythropoiesis-stimulating agents are the main pillar for treatment of anemia associated with chronic kidney disease. Methoxy polyethylene glycol-epoetin beta (MPG-EPO), also called continuous erythropoietin receptor activator, is the longest acting erythropoiesis-stimulating agent currently available. MPG-EPO is characterized by an elimination half-life of approximately 137 h and offers extended dosing intervals up to 4 weeks. Numerous phase I/II studies and a comprehensive clinical phase III program demonstrated the feasibility of MPG-EPO therapy for anemia correction and maintenance of stable hemoglobin levels in adult chronic kidney disease patients. Due to patent disputes MPG-EPO was only available outside the US market so far. In view of a prevailing US market introduction, this review focuses on efficacy and safety data from pivotal trials, summarizes recent clinical research and finally tries to substantiate potential benefits associated with the use of this anti-anemic drug.

Role of the methoxy group in immune responses to mPEG-protein conjugates

Anti-PEG antibodies have been reported to mediate the accelerated clearance of PEG-conjugated proteins and liposomes, all of which contain methoxyPEG (mPEG). The goal of this research was to assess the role of the methoxy group in the immune responses to mPEG conjugates and the potential advantages of replacing mPEG with hydroxyPEG (HO-PEG). Rabbits were immunized with mPEG, HO-PEG, or t-butoxyPEG (t-BuO-PEG) conjugates of human serum albumin, human interferon-α, or porcine uricase as adjuvant emulsions. Assay plates for enzyme-linked immunosorbent assays (ELISAs) were coated with mPEG, HO-PEG, or t-BuO-PEG conjugates of the non-cross-reacting protein, porcine superoxide dismutase (SOD). In sera from rabbits immunized with HO-PEG conjugates of interferon-α or uricase, the ratio of titers of anti-PEG antibodies detected on mPEG-SOD over HO-PEG-SOD (“relative titer”) had a median of 1.1 (range 0.9–1.5). In contrast, sera from rabbits immunized with mPEG conjugates of three proteins had relative titers with a median of 3.0 (range 1.1–20). Analyses of sera from rabbits immunized with t-BuO-PEG-albumin showed that t-butoxy groups are more immunogenic than methoxy groups. Adding Tween 20 or Tween 80 to buffers used to wash the assay plates, as is often done in ELISAs, greatly reduced the sensitivity of detection of anti-PEG antibodies. Competitive ELISAs revealed that the affinities of antibodies raised against mPEG-uricase were c. 70 times higher for 10 kDa mPEG than for 10 kDa PEG diol and that anti-PEG antibodies raised against mPEG conjugates of three proteins had >1000 times higher affinities for albumin conjugates with c. 20 mPEGs than for analogous HO-PEG-albumin conjugates. Overall, these results are consistent with the hypothesis that antibodies with high affinity for methoxy groups contribute to the loss of efficacy of mPEG conjugates, especially if multiply-PEGylated. Using monofunctionally activated HO-PEG instead of mPEG in preparing conjugates for clinical use might decrease this undesirable effect.