UK experience of ofatumumab in recurrence of focal segmental glomerulosclerosis post-kidney transplant.

BACKGROUND: Steroid-resistant nephrotic syndrome (SRNS), commonly caused by focal segmental glomerulosclerosis (FSGS), is associated with progression to stage 5 chronic kidney disease, requirement for kidney replacement therapy and a risk of disease recurrence post-kidney transplantation. Ofatumumab (OFA) is a fully humanised monoclonal antibody to CD20, with similar mechanisms of action to rituximab (RTX). METHODS: We report a case series of seven UK patients (five paediatric, two adult), all of whom developed FSGS recurrence after kidney transplantation and received OFA as part of their therapeutic intervention. All also received concomitant plasmapheresis. The 2-year outcome of these seven patients is reported, describing clinical course, kidney function and proteinuria. RESULTS: Four patients (all paediatric) achieved complete urinary remission with minimal proteinuria 12 months post-treatment. Three of those four also had normal graft function. Two patients showed partial remission-brief improvement to non-nephrotic proteinuria (197 mg/mmol) in one patient, maintained improvement in kidney function (estimated glomerular filtration rate 76 ml/min/1.73 m2) in the other. One patient did not demonstrate any response. CONCLUSIONS: OFA may represent a useful addition to therapeutic options in the management of FSGS recurrence post-transplantation, including where RTX has shown no benefit. Concomitant plasmapheresis in all patients prevents any definitive conclusion that OFA was the beneficial intervention.

Aminoaciduria in the prediction of ifosfamide-induced tubulopathy after childhood cancer: a feasibility study.

BACKGROUND: Ifosfamide, an alkylating agent used widely in the treatment of childhood malignancy, can cause many side effects including a proximal tubulopathy. Studies suggest that aminoaciduria is seen most commonly of all the biochemical abnormalities of ifosfamide-induced tubulopathy. A recent systematic review has found a paucity of data regarding the value of early markers indicating clinically significant tubulopathy. We undertook a pilot study to determine the feasibility of examining whether patients can be risk-stratified on the basis of aminoaciduria for the development of future significant ifosfamide-induced tubulopathy, to allow the evolution of appropriate follow-up strategies. We also aimed to define accrual rates, costs and clinical demands for a future larger study. METHODS: This observational study recruited 21 patients from the Leeds Paediatric Oncology service. The medical notes of each patient were reviewed for demographic and clinical data. Simultaneous samples of blood and urine were obtained. RESULTS: The investigations in the feasibility study were acceptable to patients and were minimally demanding on both clinical and laboratory staff. Financially, the cost per patient was minimal. This study was not powered to detect significant associations with TmP/GFR (ratio of renal tubular maximum reabsorption rate of phosphate to glomerular filtration rate), growth and electrolyte supplementation. However, all patients with minimal aminoaciduria (≤2 elevated urinary amino acids) had normal TmP/GFR and no need for electrolyte supplementation. CONCLUSIONS: This pilot study has shown that a larger study is feasible and may provide clinically useful data to change current practice. This should aim to establish whether the number of abnormal amino acids or the degree of abnormality is most significant in predicting clinically significant proximal tubulopathy.

Vascular access survival in children and young adults receiving long-term hemodialysis.

BACKGROUND: The delivery of long-term hemodialysis therapy in children is complicated by smaller vascular caliber and the potential lifelong requirement for hemodialysis access. Various factors have resulted in the increased use of cuffed central venous catheters (CVLs) in preference to autologous arteriovenous fistulae (AVFs) and arteriovenous synthetic grafts (AVGs). The aim of this study is to compare CVL, AVF, and AVG survival and determine factors affecting their survival. METHODS: A 20-year retrospective study was undertaken of pediatric patients receiving long-term hemodialysis therapy. Age, height, weight, body mass index, and sex were noted at each procedure, in addition to the presence of hypoalbuminemia, underlying diagnosis, type and site of vascular access, and effect of previous access surgery. The grade of operator also was noted. RESULTS: Three hundred four vascular access procedures were performed on 114 patients, with a median age at initial access formation of 12.0 years (range, 4 weeks to 21.9 years). The most common procedure was CVL insertion (182 procedures) and then AVF formation (107 procedures), with only 15 AVGs created. Median censored survival was 3.14 years (95% confidence interval, 1.22 to 5.06) for AVFs and 0.6 years (95% confidence interval, 0.20 to 1.00) for CVLs. Factors adversely affecting vascular access survival were younger age, trainee operator, presence of hypoalbuminemia, and type of access undertaken, with AVF better than CVL. CONCLUSION: This study shows increased survival of AVFs over CVLs and AVGs. Vascular access in children and adolescents may impact on future dialysis accessibility and should be undertaken by those most experienced in each technique.