Effects of rare kidney diseases on kidney failure: a longitudinal analysis of the UK National Registry of Rare Kidney Diseases (RaDaR) cohort

SGLT2-Inhibition in Patients With Alport Syndrome

Introduction

Large-scale trials showed positive outcomes of sodium-glucose cotransporter-2 inhibitors (SGLT2i) in adults with chronic kidney disease (CKD). Whether the use of SGLT2i is safe and effective in patients with the common hereditary CKD Alport syndrome (AS) has not yet been investigated specifically in larger cohorts.

Methods

This observational, multicenter, international study (NCT02378805) assessed 112 patients with AS after start of SGLT2i. The study's primary end point was change of albuminuria in albumin/g creatinine from the start of therapy.

Results

Compared to randomized trials investigating the effect of SGLT2i in CKD, the adult patients in this study were younger (aged 38 ± 14 years) and had a better estimated glomerular filtration rate (eGFR, 63 ± 35 ml/min per 1.73 m2; n = 98). Maximum follow-up was 32 months. Compared to baseline, at the first 3 follow-up visits (months 1 to 3, 4 to 8, and 9 to 15) after initiation of SGLT2i therapy, a significant reduction of albuminuria in mg albumin/g creatinine (>30%) was observed. Mean loss of eGFR was 9 ± 12 ml/min per 1.73 m2 almost 1 year after initiation of SGLT2i therapy (n = 35). At a total of 71 patient-years at risk, 0.24 adverse events (AEs) per patient-year on SGLT2i were reported.

Conclusion

This study indicates that, additive to renin-angiotensin system (RAS)-inhibition (RASi), SGLT2i have the potential to reduce the amount of albuminuria in patients with AS. Future studies are needed to investigate the long-term effects of SGLT2i on CKD progression in patients with AS to assess whether the observed reduction in albuminuria translates to a delay in kidney failure (KF).

Scoping Review of Economic Analyses of Rare Kidney Diseases

Introduction

Rare kidney diseases (RKDs) place a substantial economic burden on patients and health systems, the extent of which is unknown and may be systematically underestimated by health economic techniques. We aimed to investigate the economic burden and cost-effectiveness evidence base for RKDs.

Methods

We conducted a systematic scoping review to identify economic evaluations, health technology assessments, and cost-of-illness studies relating to RKDs, published since 2012.

Results

A total of 161 published studies, including 66 cost-of-illness studies and 95 economic evaluations; 72 grey literature reports were also included. Most published literature originated from high-income nations, particularly the USA (81 studies), and focused on a handful of diseases, notably renal cell carcinomas (70) and systemic lupus erythematosus (36). Limited evidence was identified from lower-income settings and there were few studies of genetic conditions, which make up most RKDs. Some studies demonstrated the cost-effectiveness of existing treatments; however, there were limited considerations of broader economic impacts on patients that may be important to those with RKDs. Included health technology assessments highlighted difficulties in obtaining high-quality clinical evidence for treatments in very small patient populations, and often considered equity issues and other patient impacts qualitatively alongside clinical and economic evidence in their recommendations.

Conclusion

We found large gaps in the economic evidence base for RKDs and limited adaptation of methods to account for the uniqueness of these diseases. There may be significant scope for innovation in building an investment case for RKD treatments, as well as in decision-making processes to inform investment decisions.

[Genetics in nephrology - any news?]

While genetic kidney diseases were long regarded as a rare cause of kidney failure, it has been shown in recent years that they account for a relevant proportion of cases. In cohorts of kidney transplant recipients, a monogenic cause is found in up to 30% of cases. Identifying the genetic cause of kidney disease has become much easier thanks to technological advances in DNA sequencing. The focus has now shifted to understanding the significance of the findings and identifying diagnostic gaps. It is still not possible to clarify all CKD cases of unclear aetiology. Besides very effective generic treatments for monogenic kidney disease (e.g., ACE-inhibitor use in Alport Syndrome), increasing knowledge of the pathophysiology of genetic kidney diseases has led to a growing number of targeted therapies. These include the treatment of ADPKD with Tolvaptan, which has now been in use for 10 years. Recently, exciting, and completely new approaches have been added, such as the first siRNA therapies in nephrology for primary hyperoxaluria type 1, the targeted treatment of hyperphagia in Bardet-Biedl syndrome, the therapy of APOL1-associated kidney disease or the use of the HIF-2 antagonist Belzutifan for renal cell carcinoma associated with Von-Hippel-Lindau syndrome. The new possibilities in the treatment of patients with genetic kidney diseases have also clearly revealed deficits in current patient care. Centers of excellence with extensive experience in this area therefore play an important role in improving care. This also applies to the further training of colleagues in the field. In Germany, the National Action Alliance for People with Rare Diseases (NAMSE) and the nationwide establishment of - to date - 36 centers for rare diseases play an important role in this regard.

Cardiovascular and non-renal complications of chronic kidney disease: Managing risk

Chronic kidney disease (CKD) currently affects approximately 850 million people globally and is continuing to increase in prevalence as well as in importance as a cause of death. The excess mortality related to CKD is mostly caused by an increase in cardiovascular disease. This includes atherosclerotic cardiovascular disease as many promoters of atherosclerosis, such as blood pressure, lipid levels and hypercoagulation, are increased in people with CKD. Diabetes is a leading cause of CKD contributing to the risk of CVD, and obesity is also increasingly prevalent. Management of these risk factors is therefore very important in CKD, and to reduce risk of CKD progression. Heart failure is also more prevalent in CKD and, again, many risk factors are shared. The concept of foundational pillars in the management of heart failure has been adapted to the treatment of CKD, with many organ-protective interventions, such renin-angiotensin system blockade, sodium-glucose cotransporter-2 inhibition and mineralocorticoid receptor antagonism, reducing the risk for mortality in heart failure with reduced ejection fraction, but also for progression of CKD. Atrial fibrillation is also more common with CKD and affects the management of the former. In this review these non-renal complications of CKD are discussed, along with how the risk of these complications should be managed. Many new opportunities have demonstrated heart and kidney organ protection, but implementation is a challenge.

Efficacy and Safety of Ravulizumab in IgA Nephropathy: A Phase 2 Randomized Double-Blind Placebo-Controlled Trial

Key Points

Background

The complement system plays a central role in the pathogenesis of IgA nephropathy. We present findings from a phase 2 trial of ravulizumab, a complement C5 inhibitor.

Methods

The Study of Ravulizumab in Proliferative Lupus Nephritis or IgA Nephropathy (NCT04564339) was a randomized, double-blind, placebo-controlled trial of ravulizumab in addition to standard of care. Adults with IgA nephropathy, proteinuria ≥1 g/d, and eGFR ≥30 ml/min per 1.73 m2, and on stable renin-angiotensin blockade were randomized 2:1 to ravulizumab (intravenous every 8 weeks) or placebo for 26 weeks. From week 26–50, all participants received open-label ravulizumab. The primary end point was percentage change in proteinuria from baseline to week 26. Secondary end points included change in proteinuria at week 50 and eGFR. Safety, pharmacokinetics, and pharmacodynamics were evaluated.

Results

Forty-three patients were randomized to ravulizumab and 23 to placebo. At week 26, a statistically significant reduction in proteinuria was observed with ravulizumab versus placebo: −41.9% (95% confidence interval [CI], −50.2% to −32.0%) change in urine protein with ravulizumab and −16.8% (95% CI, −31.8% to 1.6%) change with placebo (30.1% treatment effect; P = 0.005). At week 50, there was a −44.8% (95% CI, −55.1% to −32.1%) change from baseline in urine protein with ravulizumab, and in patients who crossed over from placebo to ravulizumab at week 26, the change from baseline (week 0) to week 50 was −45.1% (−58.0% to −28.4%). The least squares mean change in eGFR from baseline to week 26 with ravulizumab was 0.2 (95% CI, −2.3 to 2.7) ml/min per 1.73 m2 and with placebo was −4.5 (−7.9 to −1.1) ml/min per 1.73 m2. From baseline to week 50, the least squares mean change in eGFR with ravulizumab was −3.9 (95% CI, −6.4 to−1.3) ml/min per 1.73 m2, and in patients who crossed over from placebo to ravulizumab at week 26, it was −6.3 (−9.7 to −2.9) ml/min per 1.73 m2. Ravulizumab was well tolerated, with an adverse event profile similar to that for placebo.

Conclusions

An early, sustained, and clinically meaningful reduction in proteinuria and trend toward stabilization of eGFR were observed with ravulizumab versus placebo. A phase 3 trial (NCT06291376) is enrolling.

Clinical Trial registry name and registration number:

Study of Ravulizumab in Proliferative Lupus Nephritis or IgA Nephropathy, NCT04564339.

Sodium-glucose cotransporter-2 (SGLT-2) inhibitors for adults with chronic kidney disease: a clinical practice guideline

CLINICAL QUESTION

What is the impact of sodium-glucose cotransporter-2 (SGLT-2) inhibitors on survival and on cardiovascular and kidneyoutcomes for adults living with chronic kidney disease (CKD)?

CURRENT PRACTICE

Few therapies slow kidney disease progression and improve long term prognosis for adults living with CKD. SGLT-2 inhibitors have demonstrated cardiovascular and kidney benefits in adults with CKD with and without type 2 diabetes. Existing guidance for SGLT-2 inhibitors does not account for the totality of current best evidence for adults with CKD and does not provide fully stratified treatment effects and recommendations across all risk groups based on risk of CKD progression and complications.

RECOMMENDATIONS

The guideline panel considered evidence regarding benefits and harms of SGLT-2 inhibitor therapy for adults with CKD over a five year period, along with contextual factors, and provided the following recommendations:1. For adults at low risk of CKD progression and complications, we suggest administering SGLT-2 inhibitors (weak recommendation in favour)2. For adults at moderate risk of CKD progression and complications, we suggest administering SGLT-2 inhibitors (weak recommendation in favour)3. For adults at high risk of CKD progression and complications, we recommend administering SGLT-2 inhibitors (strong recommendation in favour)4. For adults at very high risk of CKD progression and complications, we recommend administering SGLT-2 inhibitors (strong recommendation in favour).Recommendations are applicable to all adults with CKD, irrespective of type 2 diabetes status.

HOW THIS GUIDELINE WAS CREATED

An international panel including patients, clinicians, and methodologists produced these recommendations following standards for trustworthy guidelines and using the GRADE approach. The panel identified typical risk strata of adults with CKD (from low to very high risk of CKD progression and related complications) using the classification system developed by Kidney Disease Improving Global Outcomes (KDIGO), and applied an individual patient perspective in moving from evidence to recommendations. Effects of SGLT-2 inhibitors were interpreted in absolute terms applicable to different risk strata with varying baseline risks for outcomes of benefit over a five year period. The panel explicitly considered the balance of benefits, harms, and burdens of starting an SGLT-2 inhibitor, incorporating the values and preferences of adults with different risk profiles. Interactive evidence summaries and decision aids accompany multilayered recommendations, developed in an online authoring and publication platform (www.magicapp.org) that allows reuse and adaptation.

THE EVIDENCE

A linked systematic review and pairwise meta-analysis (13 trials including 29 614 participants) of benefits and harms associated with SGLT-2 inhibitors in adults with CKD with or without type 2 diabetes informed guidance. Among individuals at very high risk of CKD progression and complications, moderate to high certainty evidence shows SGLT-2 inhibitors (relative to placebo or standard care without SGLT-2 inhibitors) decrease all-cause and cardiovascular mortality, hospitalisation for heart failure, kidney failure, non-fatal myocardial infarction, and non-fatal stroke. Among individuals at high risk, moderate to high certainty evidence shows SGLT-2 inhibitors result in similar benefits across outcomes except demonstrating little or no effect on hospitalisation for heart failure and kidney failure. Among individuals at moderate and low risk, moderate to high certainty evidence shows SGLT-2 inhibitors probably reduce all-cause mortality and non-fatal stroke, with little or no effect for other outcomes of benefit. Risk-stratified estimates were unavailable for outcomes of harm; the panel therefore considered absolute effects summarised across risk strata. SGLT-2 inhibitors are associated with little or no effect on acute kidney injury requiring dialysis, bone fractures, lower limb amputations, ketoacidosis, genital infections, or symptomatic hypovolaemia, although a residual possibility of harms at the individual patient level remains.

UNDERSTANDING THE RECOMMENDATION

In order to apply recommendations, clinicians must appropriately identify adults with CKD, consider the underlying aetiology, and risk stratify them based on glomerular filtration rate (estimated or measured) and degree of albuminuria. In addition to classifying individuals into risk strata, further estimation of a given patient's risk based on the extent of their kidney disease and other comorbidities may be warranted to inform individual-level decisions and shared decision making. Available risk calculators may help estimate a given patient's risk of CKD progression and complications.

Description and Cross-Sectional Analyses of 25,880 Adults and Children in the UK National Registry of Rare Kidney Diseases Cohort

Introduction

The National Registry of Rare Kidney Diseases (RaDaR) collects data from people living with rare kidney diseases across the UK, and is the world's largest, rare kidney disease registry. We present the clinical demographics and renal function of 25,880 prevalent patients and sought evidence of bias in recruitment to RaDaR.

Methods

RaDaR is linked with the UK Renal Registry (UKRR, with which all UK patients receiving kidney replacement therapy [KRT] are registered). We assessed ethnicity and socioeconomic status in the following: (i) prevalent RaDaR patients receiving KRT compared with patients with eligible rare disease diagnoses receiving KRT in the UKRR, (ii) patients recruited to RaDaR compared with all eligible unrecruited patients at 2 renal centers, and (iii) the age-stratified ethnicity distribution of RaDaR patients with autosomal dominant polycystic kidney disease (ADPKD) was compared to that of the English census.

Results

We found evidence of disparities in ethnicity and social deprivation in recruitment to RaDaR; however, these were not consistent across comparisons. Compared with either adults recruited to RaDaR or the English population, children recruited to RaDaR were more likely to be of Asian ethnicity (17.3% vs. 7.5%, P-value < 0.0001) and live in more socially deprived areas (30.3% vs. 17.3% in the most deprived Index of Multiple Deprivation (IMD) quintile, P-value < 0.0001).

Conclusion

We observed no evidence of systematic biases in recruitment of patients into RaDaR; however, the data provide empirical evidence of negative economic and social consequences (across all ethnicities) experienced by families with children affected by rare kidney diseases.

Developing Therapies for C3 Glomerulopathy: Report of the Kidney Health Initiative C3 Glomerulopathy Trial Endpoints Work Group

Randomized clinical trials are underway to evaluate the efficacy of novel agents targeting the alternative complement pathway in patients with C3 glomerulopathy (C3G), a rare glomerular disease. The Kidney Health Initiative convened a panel of experts in C3G to ( 1 ) assess the data supporting the use of the prespecified trial end points as measures of clinical benefit and ( 2 ) opine on efficacy findings they would consider compelling as treatment(s) of C3G in native kidneys. Two subpanels of the C3G Trial Endpoints Work Group reviewed the available evidence and uncertainties for the association between the three prespecified end points-( 1 ) proteinuria, ( 2 ) eGFR, and ( 3 ) histopathology-and anticipated outcomes. The full work group provided feedback on the summaries provided by the subpanels and on what potential treatment effects on the proposed end points they would consider compelling to support evidence of an investigational product's effectiveness for treating C3G. Members of the full work group agreed with the characterization of the data, evidence, and uncertainties, supporting the end points. Given the limitations of the available data, the work group was unable to define a minimum threshold for change in any of the end points that might be considered clinically meaningful. The work group concluded that a favorable treatment effect on all three end points would provide convincing evidence of efficacy in the setting of a therapy that targeted the complement pathway. A therapy might be considered effective in the absence of complete alignment in all three end points if there was meaningful lowering of proteinuria and stabilization or improvement in eGFR. The panel unanimously supported efforts to foster data sharing between academic and industry partners to address the gaps in the current knowledge identified by the review of the end points in the aforementioned trials.