Cardiovascular outcomes in patients with homozygous familial hypercholesterolaemia on lipoprotein apheresis initiated during childhood: long-term follow-up of an international cohort from two registries.

BACKGROUND: Homozygous familial hypercholesterolaemia (HoFH) is a rare genetic disease characterised by extremely high plasma LDL cholesterol from birth, causing atherosclerotic cardiovascular disease at a young age. Lipoprotein apheresis in combination with lipid-lowering drugs effectively reduce LDL cholesterol, but long-term health outcomes of such treatment are unknown. We aimed to investigate the long-term cardiovascular outcomes associated with lipoprotein apheresis initiated in childhood or adolescence. METHODS: In this cohort study, data were drawn from the HoFH International Clinical Collaboration (HICC) and the international registry for Children with Homozygous Hypercholesterolemia on Lipoprotein Apheresis (CHAIN). An overall cohort included patients diagnosed with HoFH aged 0-18 years who were alive and in follow-up between Jan 1, 2010, and Nov 8, 2021, and whose high plasma LDL cholesterol concentrations made them eligible for lipoprotein apheresis. To compare cardiovascular outcomes, patients who initiated lipoprotein apheresis in childhood (lipoprotein apheresis group) and patients who only received lipid-lowering drugs (pharmacotherapy-only group) were matched by sex and untreated plasma LDL cholesterol concentrations. The primary outcome was a composite of cardiovascular death, myocardial infarction, ischaemic stroke, percutaneous coronary intervention, coronary artery bypass grafting, aortic valve replacement, peripheral artery disease, carotid endarterectomy, angina pectoris, and supra-aortic or aortic stenosis (collectively referred to as atherosclerotic cardiovascular disease), for which survival analyses were performed in the matched cohort. Cox regression analyses were used to compare disease-free survival between cohorts and to calculate hazard ratio (HR) and 95% CI adjusted for sex, age at diagnosis, untreated plasma LDL cholesterol concentration, and number of lipid-lowering therapies other than lipoprotein apheresis. FINDINGS: The overall cohort included 404 patients with a median age at diagnosis of 6·0 years (IQR 3·0-9·5) and median untreated plasma LDL cholesterol of 17·8 mmol/L (14·7-20·8). The matched cohorts included 250 patients (125 patients per group), with a median untreated LDL cholesterol of 17·2 mmol/L (14·8-19·7). Mean reduction in plasma LDL cholesterol concentrations between baseline and final follow-up was greater in the lipoprotein apheresis group (-55% [95% CI -60 to -51] vs -31% [-36 to -25]; p<0·0001). Patients in the lipoprotein apheresis group had longer atherosclerotic cardiovascular disease-free survival (adjusted HR 0·52 [95% CI 0·32-0·85]) and longer cardiovascular death-free survival (0·0301 [0·0021-0·4295]). Cardiovascular death was more common in the pharmacotherapy-only group than in the lipoprotein apheresis group (ten [8%] vs one [1%]; p=0·010), whereas median age at coronary artery bypass grafting was lower in the lipoprotein apheresis group than in the pharmacotherapy-only group (15·0 years [IQR 12·0-24·0] vs 30·5 years [19·0-33·8]; p=0·037). INTERPRETATION: Among patients with HoFH, lipoprotein apheresis initiated during childhood and adolescence is associated with reduced long-term risk of atherosclerotic cardiovascular disease and death, and clear benefits of early initiation of high-frequency treatment on reducing plasma cholesterol were found. Consensus recommendations are now needed to guide more widespread and timely use of lipoprotein apheresis for children with HoFH, and research is required to further optimise treatment and ensure benefits of early and aggressive treatment delivery are balanced against effects on quality of life. FUNDING: Amsterdam University Medical Centers, Location Academic Medical Center; Perelman School of Medicine at the University of Pennsylvania; European Atherosclerosis Society; and the US National Heart, Lung, and Blood Institute, National Institutes of Health.

Clinical practice recommendations on lipoprotein apheresis for children with homozygous familial hypercholesterolaemia: An expert consensus statement from ERKNet and ESPN.

Homozygous familial hypercholesterolaemia is a life-threatening genetic condition, which causes extremely elevated LDL-C levels and atherosclerotic cardiovascular disease very early in life. It is vital to start effective lipid-lowering treatment from diagnosis onwards. Even with dietary and current multimodal pharmaceutical lipid-lowering therapies, LDL-C treatment goals cannot be achieved in many children. Lipoprotein apheresis is an extracorporeal lipid-lowering treatment, which is used for decades, lowering serum LDL-C levels by more than 70% directly after the treatment. Data on the use of lipoprotein apheresis in children with homozygous familial hypercholesterolaemia mainly consists of case-reports and case-series, precluding strong evidence-based guidelines. We present a consensus statement on lipoprotein apheresis in children based on the current available evidence and opinions from experts in lipoprotein apheresis from over the world. It comprises practical statements regarding the indication, methods, treatment goals and follow-up of lipoprotein apheresis in children with homozygous familial hypercholesterolaemia and on the role of lipoprotein(a) and liver transplantation.

Clinical practice recommendations on lipoprotein apheresis for children with homozygous familial hypercholesterolemia: an expert consensus statement from ERKNet and ESPN.

Homozygous familial hypercholesterolaemia is a life-threatening genetic condition, which causes extremely elevated LDL-C levels and atherosclerotic cardiovascular disease very early in life. It is vital to start effective lipid-lowering treatment from diagnosis onwards. Even with dietary and current multimodal pharmaceutical lipid-lowering therapies, LDL-C treatment goals cannot be achieved in many children. Lipoprotein apheresis is an extracorporeal lipid-lowering treatment, which is well established since three decades, lowering serum LDL-C levels by more than 70% per session. Data on the use of lipoprotein apheresis in children with homozygous familial hypercholesterolaemia mainly consists of case-reports and case-series, precluding strong evidence-based guidelines. We present a consensus statement on lipoprotein apheresis in children based on the current available evidence and opinions from experts in lipoprotein apheresis from over the world. It comprises practical statements regarding the indication, methods, treatment targets and follow-up of lipoprotein apheresis in children with homozygous familial hypercholesterolaemia and on the role of lipoprotein(a) and liver transplantation.

Determinants of Kidney Failure in Primary Hyperoxaluria Type 1: Findings of the European Hyperoxaluria Consortium.

Introduction: Primary hyperoxaluria type 1 (PH1) has a highly heterogeneous disease course. Apart from the c.508G>A (p.Gly170Arg) AGXT variant, which imparts a relatively favorable outcome, little is known about determinants of kidney failure. Identifying these is crucial for disease management, especially in this era of new therapies. Methods: In this retrospective study of 932 patients with PH1 included in the OxalEurope registry, we analyzed genotype-phenotype correlations as well as the impact of nephrocalcinosis, urolithiasis, and urinary oxalate and glycolate excretion on the development of kidney failure, using survival and mixed model analyses. Results: The risk of developing kidney failure was the highest for 175 vitamin-B6 unresponsive ("null") homozygotes and lowest for 155 patients with c.508G>A and c.454T>A (p.Phe152Ile) variants, with a median age of onset of kidney failure of 7.8 and 31.8 years, respectively. Fifty patients with c.731T>C (p.Ile244Thr) homozygote variants had better kidney survival than null homozygotes (P = 0.003). Poor outcomes were found in patients with other potentially vitamin B6-responsive variants. Nephrocalcinosis increased the risk of kidney failure significantly (hazard ratio [HR] 3.17 [2.03-4.94], P < 0.001). Urinary oxalate and glycolate measurements were available in 620 and 579 twenty-four-hour urine collections from 117 and 87 patients, respectively. Urinary oxalate excretion, unlike glycolate, was higher in patients who subsequently developed kidney failure (P = 0.034). However, the 41% intraindividual variation of urinary oxalate resulted in wide confidence intervals. Conclusion: In conclusion, homozygosity for AGXT null variants and nephrocalcinosis were the strongest determinants for kidney failure in PH1.

Office blood pressure versus ambulatory blood pressure measurement in childhood obesity.

BACKGROUND: The prevalence of obesity-related co-morbidities is rising parallel to the childhood obesity epidemic. High blood pressure (BP), as one of these co-morbidities, is detected nowadays at increasingly younger ages. The diagnosis of elevated BP and hypertension, especially in the childhood population, presents a challenge to clinicians. The added value of ambulatory blood pressure measurement (ABPM) in relation to office blood pressure (OBP) measurements in obese children is unclear. Furthermore, it is unknown how many overweight and obese children have an abnormal ABPM pattern. In this study we evaluated ABPM patterns in a population of overweight and obese children and adolescents, and compared these patterns with regular OBP measurements. METHODS: In this cross-sectional study in overweight or obese children and adolescents aged 4-17 years who were referred to secondary pediatric obesity care in a large general hospital in The Netherlands, OBP was measured during a regular outpatient clinic visit. Additionally, all participants underwent a 24-hour ABPM on a regular week-day. Outcome measures were OBP, mean ambulatory SBP and DBP, BP load (percentage of readings above the ambulatory 95th blood pressure percentiles), ambulatory BP pattern (normal BP, white-coat hypertension, elevated BP, masked hypertension, ambulatory hypertension), and BP dipping. RESULTS: We included 82 children aged 4-17 years. They had a mean BMI Z-score of 3.3 (standard deviation 0.6). Using ABPM, 54.9% of the children were normotensive (95% confidence interval 44.1-65.2), 26.8% had elevated BP, 9.8% ambulatory hypertension, 3.7% masked hypertension, and 4.9% white-coat hypertension. An isolated night-time BP load > 25% was detected in almost a quarter of the children. 40% of the participants lacked physiologic nocturnal systolic BP dipping. In the group of children with normal OBP, 22.2% turned out to have either elevated BP or masked hypertension on ABPM. CONCLUSIONS: In this study a high prevalence of abnormal ABPM patterns in overweight or obese children and adolescents was detected. Additionally, OBP poorly correlated with the child's actual ABPM pattern. Herewith, we emphasized the usefulness of ABPM as an important diagnostic tool in this population.

Disparities in treatment and outcome of kidney replacement therapy in children with comorbidities: an ESPN/ERA Registry study.

Background: Data on comorbidities in children on kidney replacement therapy (KRT) are scarce. Considering their high relevance for prognosis and treatment, this study aims to analyse the prevalence and implications of comorbidities in European children on KRT. Methods: We included data from patients <20 years of age when commencing KRT from 2007 to 2017 from 22 European countries within the European Society of Paediatric Nephrology/European Renal Association Registry. Differences between patients with and without comorbidities in access to kidney transplantation (KT) and patient and graft survival were estimated using Cox regression. Results: Comorbidities were present in 33% of the 4127 children commencing KRT and the prevalence has steadily increased by 5% annually since 2007. Comorbidities were most frequent in high-income countries (43% versus 24% in low-income countries and 33% in middle-income countries). Patients with comorbidities had a lower access to transplantation {adjusted hazard ratio [aHR] 0.67 [95% confidence interval (CI) 0.61-0.74]} and a higher risk of death [aHR 1.79 (95% CI 1.38-2.32)]. The increased mortality was only seen in dialysis patients [aHR 1.60 (95% CI 1.21-2.13)], and not after KT. For both outcomes, the impact of comorbidities was stronger in low-income countries. Graft survival was not affected by the presence of comorbidities [aHR for 5-year graft failure 1.18 (95% CI 0.84-1.65)]. Conclusions: Comorbidities have become more frequent in children on KRT and reduce their access to transplantation and survival, especially when remaining on dialysis. KT should be considered as an option in all paediatric KRT patients and efforts should be made to identify modifiable barriers to KT for children with comorbidities.

Clinical practice recommendations for primary hyperoxaluria: an expert consensus statement from ERKNet and OxalEurope.

Primary hyperoxaluria (PH) is an inherited disorder that results from the overproduction of endogenous oxalate, leading to recurrent kidney stones, nephrocalcinosis and eventually kidney failure; the subsequent storage of oxalate can cause life-threatening systemic disease. Diagnosis of PH is often delayed or missed owing to its rarity, variable clinical expression and other diagnostic challenges. Management of patients with PH and kidney failure is also extremely challenging. However, in the past few years, several new developments, including new outcome data from patients with infantile oxalosis, from transplanted patients with type 1 PH (PH1) and from patients with the rarer PH types 2 and 3, have emerged. In addition, two promising therapies based on RNA interference have been introduced. These developments warrant an update of existing guidelines on PH, based on new evidence and on a broad consensus. In response to this need, a consensus development core group, comprising (paediatric) nephrologists, (paediatric) urologists, biochemists and geneticists from OxalEurope and the European Rare Kidney Disease Reference Network (ERKNet), formulated and graded statements relating to the management of PH on the basis of existing evidence. Consensus was reached following review of the recommendations by representatives of OxalEurope, ESPN, ERKNet and ERA, resulting in 48 practical statements relating to the diagnosis and management of PH, including consideration of conventional therapy (conservative therapy, dialysis and transplantation), new therapies and recommendations for patient follow-up.

Lumasiran for Advanced Primary Hyperoxaluria Type 1: Phase 3 ILLUMINATE-C Trial.

RATIONALE & OBJECTIVE: Lumasiran reduces urinary and plasma oxalate (POx) in patients with primary hyperoxaluria type 1 (PH1) and relatively preserved kidney function. ILLUMINATE-C evaluates the efficacy, safety, pharmacokinetics, and pharmacodynamics of lumasiran in patients with PH1 and advanced kidney disease. STUDY DESIGN: Phase 3, open-label, single-arm trial. SETTING & PARTICIPANTS: Multinational study; enrolled patients with PH1 of all ages, estimated glomerular filtration rate ≤45 mL/min/1.73 m2 (if age ≥12 months) or increased serum creatinine level (if age <12 months), and POx ≥20 µmol/L at screening, including patients with or without systemic oxalosis. INTERVENTION: Lumasiran administered subcutaneously; 3 monthly doses followed by monthly or quarterly weight-based dosing. OUTCOME: Primary end point: percent change in POx from baseline to month 6 (cohort A; not receiving hemodialysis at enrollment) and percent change in predialysis POx from baseline to month 6 (cohort B; receiving hemodialysis at enrollment). Pharmacodynamic secondary end points: percent change in POx area under the curve between dialysis sessions (cohort B only); absolute change in POx; percent and absolute change in spot urinary oxalate-creatinine ratio; and 24-hour urinary oxalate adjusted for body surface area. RESULTS: All patients (N = 21; 43% female; 76% White) completed the 6-month primary analysis period. Median age at consent was 8 (range, 0-59) years. For the primary end point, least-squares mean reductions in POx were 33.3% (95% CI, -15.2% to 81.8%) in cohort A (n = 6) and 42.4% (95% CI, 34.2%-50.7%) in cohort B (n = 15). Improvements were also observed in all pharmacodynamic secondary end points. Most adverse events were mild or moderate. No patient discontinued treatment or withdrew from the study. The most commonly reported lumasiran-related adverse events were injection-site reactions, all of which were mild and transient. LIMITATIONS: Single-arm study without placebo control. CONCLUSIONS: Lumasiran resulted in substantial reductions in POx with acceptable safety in patients with PH1 who have advanced kidney disease, supporting its efficacy and safety in this patient population. FUNDING: Alnylam Pharmaceuticals. TRIAL REGISTRATION: Registered at ClinicalTrials.gov with study number NCT04152200 and at EudraCT with study number 2019-001346-17. PLAIN-LANGUAGE SUMMARY: Primary hyperoxaluria type 1 (PH1) is a rare genetic disease characterized by excessive hepatic oxalate production that frequently causes kidney failure. Lumasiran is an RNA interference therapeutic that is administered subcutaneously for the treatment of PH1. Lumasiran has been shown to reduce oxalate levels in the urine and plasma of patients with PH1 who have relatively preserved kidney function. In the ILLUMINATE-C study, the efficacy and safety of lumasiran were evaluated in patients with PH1 and advanced kidney disease, including a cohort of patients undergoing hemodialysis. During the 6-month primary analysis period, lumasiran resulted in substantial reductions in plasma oxalate with acceptable safety in patients with PH1 complicated by advanced kidney disease.

Risk factors for neurocognitive impairment and the relation with structural brain abnormality in children and young adults with severe chronic kidney disease.

BACKGROUND: Severe chronic kidney disease (CKD) in children and young adults has shown to be associated with abnormal brain development, which may contribute to neurocognitive impairments. We aimed to investigate risk factors for neurocognitive impairment and investigate the relation with structural brain abnormalities in young severe CKD patients. METHODS: This cross-sectional study includes 28 patients with severe CKD (eGFR < 30), aged 8-30 years (median 18.5 years), on different treatment modalities (pre-dialysis [n = 8], dialysis [n = 8], transplanted [n = 12]). We assessed neurocognitive functioning using a comprehensive test battery and brain structure by magnetic resonance imaging metrics of brain volume and white matter integrity (fractional anisotropy [FA] and mean diffusivity [MD] measured with diffusion tensor imaging). Multivariate regression and mediation analyses were performed between clinical CKD parameters, brain structure, and neurocognitive outcome. RESULTS: A combination of risk factors (e.g., longer time since kidney transplantation, longer dialysis duration and late CKD onset) was significantly associated with lower intelligence and/or worse processing speed and working memory. Lower FA in a cluster of white matter tracts was associated with lower intelligence and mediated the relation between clinical risk factors and lower intelligence. CONCLUSIONS: Young severe CKD patients with a prolonged duration of kidney replacement therapy, either dialysis or transplantation are at particular risk for impairments in intelligence, processing speed, and working memory. Disrupted white matter integrity may importantly contribute to these neurocognitive impairments. Prospective, longitudinal studies are needed to elucidate the mechanisms involved in CKD and treatment that affect white matter integrity and neurocognitive outcome in young patients. A higher resolution version of the Graphical abstract is available as Supplementary information.

Improved Outcome of Infantile Oxalosis Over Time in Europe: Data From the OxalEurope Registry.

Introduction: Infantile oxalosis is the most severe form of primary hyperoxaluria type 1 (PH1), with onset of end-stage kidney disease (ESKD) during infancy. We aimed to analyze the outcome of these patients as our current understanding is limited owing to a paucity of reports. Methods: A retrospective registry study was conducted using data from the OxalEurope registry. All PH1 patients with ESKD onset at age <1 year were analyzed. Results: We identified 95 patients born between 1980 and 2018 with infantile oxalosis. Median (interquartile range [IQR]) age at ESKD was 0.4 (0.3-0.5) year. There were 4 patients diagnosed by family screening who developed ESKD despite early diagnosis. There were 11 patients who had biallelic missense mutations associated with vitamin B6 responsiveness. Of 89 patients, 27 (30%) died at a median age of 1.4 (0.6-2.0) years (5-year patient survival of 69%). Systemic oxalosis was described in 54 of 56 screened patients (96%). First transplantation was performed at a median age of 1.7 (1.3-2.9) years. In 42 cases, this procedure was a combined liver-kidney transplantation (LKTx), and in 23 cases, liver transplantations (LTx) was part of a sequential procedure. Survival rates of both strategies were similar. Patient survival was significantly higher in patients born after 2000. Intrafamilial phenotypic variability was present in 14 families of patients with infantile oxalosis. Conclusion: Nearly all screened patients with infantile oxalosis developed systemic disease. Mortality is still high but has significantly improved over time and might further improve under new therapies. The intrafamilial phenotypic variability warrants further investigation.

Primary hyperoxaluria: the pediatric nephrologist's point of view.

The clinical presentation of primary hyperoxaluria in children ranges from mildly symptomatic nephrocalcinosis to very early onset end-stage kidney failure with systemic oxalosis, a devastating complication. We review the various manifestations of pediatric hyperoxaluria, treatment options for children with preserved kidney function and appropriate dialysis regimens. Liver or combined liver/kidney transplantation is currently the only definitive treatment for primary hyperoxaluria type 1, but novel RNA interference treatments offer hope for the future. Finally, we address the medical and ethical dilemmas facing pediatricians treating children with hyperoxaluria.

Randomized Clinical Trial on the Long-Term Efficacy and Safety of Lumasiran in Patients With Primary Hyperoxaluria Type 1.

Introduction: Primary hyperoxaluria type 1 (PH1) is a rare genetic disease caused by hepatic overproduction of oxalate, leading to kidney stones, nephrocalcinosis, kidney failure, and systemic oxalosis. In the 6-month double-blind period (DBP) of ILLUMINATE-A, a phase 3, randomized, placebo-controlled trial in patients with PH1 ≥6 years old, treatment with lumasiran, an RNA interference therapeutic, led to substantial reductions in urinary oxalate (UOx) levels. Methods: We report data to month 12 in the extension period (EP) of ILLUMINATE-A, including patients who continued lumasiran (lumasiran/lumasiran) or crossed over from placebo to lumasiran (placebo/lumasiran). Results: In the lumasiran/lumasiran group (n = 24), the reduction in 24-hour UOx level was sustained to month 12 (mean reduction from baseline, 66.9% at month 6; 64.1% at month 12). The placebo/lumasiran group (n = 13) had a similar time course and magnitude of 24-hour UOx reduction (mean reduction, 57.3%) after 6 months of lumasiran. Kidney stone event rates seemed to be lower after 6 months of lumasiran in both groups compared with the 12 months before consent, and this reduction was maintained at month 12 in the lumasiran/lumasiran group. At study start, 71% of patients in the lumasiran/lumasiran group and 92% in the placebo/lumasiran group had nephrocalcinosis. Nephrocalcinosis grade improved after 6 months of lumasiran in the lumasiran/lumasiran and placebo/lumasiran groups (13% and 8% of patients, respectively). After an additional 6 months of lumasiran, 46% of patients had improvement in nephrocalcinosis grade within the lumasiran/lumasiran group. Estimated glomerular filtration rate (eGFR) remained stable during the course of lumasiran treatment. The most common adverse events (AEs) related to lumasiran were mild, transient injection-site reactions (ISRs). Conclusion: Long-term lumasiran treatment enabled sustained lowering of UOx levels with acceptable safety and encouraging results on clinical outcomes.

Long-Term Transplantation Outcomes in Patients With Primary Hyperoxaluria Type 1 Included in the European Hyperoxaluria Consortium (OxalEurope) Registry.

INTRODUCTION: In primary hyperoxaluria type 1 (PH1), oxalate overproduction frequently causes kidney stones, nephrocalcinosis, and kidney failure. As PH1 is caused by a congenital liver enzyme defect, combined liver-kidney transplantation (CLKT) has been recommended in patients with kidney failure. Nevertheless, systematic analyses on long-term transplantation outcomes are scarce. The merits of a sequential over combined procedure regarding kidney graft survival remain unclear as is the place of isolated kidney transplantation (KT) for patients with vitamin B6-responsive genotypes. METHODS: We used the OxalEurope registry for retrospective analyses of patients with PH1 who underwent transplantation. Analyses of crude Kaplan-Meier survival curves and adjusted relative hazards from the Cox proportional hazards model were performed. RESULTS: A total of 267 patients with PH1 underwent transplantation between 1978 and 2019. Data of 244 patients (159 CLKTs, 48 isolated KTs, 37 sequential liver-KTs [SLKTs]) were eligible for comparative analyses. Comparing CLKTs with isolated KTs, adjusted mortality was similar in patients with B6-unresponsive genotypes but lower after isolated KT in patients with B6-responsive genotypes (adjusted hazard ratio 0.07, 95% CI: 0.01-0.75, P = 0.028). CLKT yielded higher adjusted event-free survival and death-censored kidney graft survival in patients with B6-unresponsive genotypes (P = 0.025, P < 0.001) but not in patients with B6-responsive genotypes (P = 0.145, P = 0.421). Outcomes for 159 combined procedures versus 37 sequential procedures were comparable. There were 12 patients who underwent pre-emptive liver transplantation (PLT) with poor outcomes. CONCLUSION: The CLKT or SLKT remains the preferred transplantation modality in patients with PH1 with B6-unresponsive genotypes, but isolated KT could be an alternative approach in patients with B6-responsive genotypes.

Safety, pharmacodynamics, and exposure-response modeling results from a first-in-human phase 1 study of nedosiran (PHYOX1) in primary hyperoxaluria.

Primary hyperoxaluria (PH) is a family of ultra-rare autosomal recessive inherited disorders of hepatic glyoxylate metabolism characterized by oxalate overproduction. Nedosiran is an RNA interference agent that inhibits hepatic lactate dehydrogenase, the enzyme responsible for the common, final step of oxalate production in all three genetic subtypes of PH. Here, we assessed in a two-part, randomized, single-ascending-dose, phase 1 study (PHYOX1) the safety, pharmacokinetics, pharmacodynamics, and exposure-response of subcutaneous nedosiran in 25 healthy participants (Group A) and 18 patients with PH1 or PH2 (Group B). Group A received nedosiran (0.3, 1.5, 3.0, 6.0, then 12.0 mg/kg) or placebo, and Group B received open-label nedosiran (1.5, 3.0, or 6.0 mg/kg). No significant safety concerns were identified. Injection site reactions (four or more hours post dose) occurred in 13.3% of participants in Group A and 27.8% of participants in Group B. Mean maximum reduction in 24-hour urinary oxalate excretion from baseline to day 57 (end of study) across Group B dose cohorts was 55% (range: 22%-100%) after single-dose nedosiran, with 33% participants reaching normal 24-hour urinary oxalate excretion. Based on the available modeling and simulation data, a fixed monthly dose of nedosiran 160 mg (free acid; equivalent to 170 mg sodium salt) in adults was associated with the highest proportion of simulated individuals achieving normal or near-normal 24-hour urinary oxalate excretion and fewest fluctuations in urinary oxalate response. Thus, single-dose nedosiran demonstrated acceptable safety and evidence of a pharmacodynamic effect in both PH1 and PH2 subpopulations consistent with its mechanism of action.

Structural brain abnormalities in children and young adults with severe chronic kidney disease.

BACKGROUND: The pathophysiology of neurological dysfunction in severe chronic kidney disease (CKD) in children and young adults is largely unknown. We aimed to investigate brain volumes and white matter integrity in this population and explore brain structure under different treatment modalities. METHODS: This cross-sectional study includes 24 patients with severe CKD (eGFR < 30) aged 8-30 years (median = 18.5, range = 9.1-30.5) on different therapy modalities (pre-dialysis, n = 7; dialysis, n = 7; transplanted, n = 10) and 21 healthy controls matched for age, sex, and parental educational level. Neuroimaging targeted brain volume using volumetric analysis on T1 scans and white matter integrity with tract-based spatial statistics and voxel-wise regression on diffusion tensor imaging (DTI) data. RESULTS: CKD patients had lower white matter integrity in a widespread cluster of primarily distal white matter tracts compared to healthy controls. Furthermore, CKD patients had smaller volume of the nucleus accumbens relative to healthy controls, while no evidence was found for abnormal volumes of gray and white matter or other subcortical structures. Longer time since successful transplantation was related to lower white matter integrity. Exploratory analyses comparing treatment subgroups suggest lower white matter integrity and smaller volume of the nucleus accumbens in dialysis and transplanted patients relative to healthy controls. CONCLUSIONS: Young CKD patients seem at risk for widespread disruption of white matter integrity and to some extent smaller subcortical volume (i.e., nucleus accumbens). Especially patients on dialysis therapy and patients who received a kidney transplant may be at risk for disruption of white matter integrity and smaller volume of the nucleus accumbens.