New hypoglycemic agents and the kidney: what do the major trials tell us? [version 1; referees: 2 approved]

As the burden of diabetic kidney disease continues to expand, new therapies to preserve renal function or prevent diabetic nephropathy are urgently needed. In the past decade, a number of new hypoglycemic classes have emerged, each with a unique profile of action and benefits. Here we review the impact of glycemic control on renal outcomes and the results of the major clinical trials of glucagon-like peptide 1 (GLP-1) agonists, dipeptidyl peptidase-4 (DPP-4) inhibitors, and sodium–glucose co-transporter 2 (SGLT2) inhibitors. Both GLP-1 agonists and SGLT2 inhibitors consistently demonstrate renal benefits. Further studies of these new agents in different patient groups and in comparison to (or in combination with) other treatments are required to better define their role in combating the burden of diabetic kidney disease

New clinical trial designs for establishing drug efficacy and safety in a precision medicine era

Despite advances in pharmacotherapy, diabetic kidney disease (DKD) remains associated with a high burden of micro- and macrovascular complications often leading to premature mortality. New therapies are highly desirable to mitigate the burden of this disease. However, there are a number of barriers that hamper drug development in DKD. These include, amongst others, the lengthy and complex clinical trials required to prove drug efficacy and safety, inefficiencies in clinical trial conduct, and the high costs associated with these development programs. In this review a number of aspects are discussed, aiming to identify opportunities to transform and innovate drug development for DKD. Many clinical trials in DKD, as well as in other areas, face difficulties in timely and efficient enrolment of participants. To address this issue a network of sites should be created that are continuously recruiting individuals with DKD and collecting crucial information that can be used to understand prognosis and prognostic factors, and more importantly to serve as a pool of participants for recruitment to randomized trials. Second, the current clinical endpoints are late events in the progression of DKD. Endpoints based on lesser declines in estimated glomerular filtration rate (eGFR) or changes in albuminuria can shorten follow-up and/or lead to smaller and cheaper trials. Enrichment by enrolling clinical trial populations based on biomarker profiles is another approach that may facilitate clinical trial efficiency and conduct. Biomarkers can be used to individualize treatment by targeting populations more likely to respond leading to smaller and more efficient trials. Finally, using new trial design such as basket, umbrella or more broadly platform trials to assess a number of therapies simultaneously offers the potential to transform the drug development process in DKD. There are a number of opportunities to transform development approaches for new therapies for DKD. Platform trials along with appropriate biomarker-based enrichment strategies offer the possibility to foster drug development in a precision medicine era

Effects of canagliflozin on serum potassium in the CANagliflozin cardioVascular Assessment Study (CANVAS) Program

Background: The sodium-glucose cotransporter 2 inhibitor canagliflozin has been shown to reduce the risk of cardiovascular and renal events in patients with Type 2 diabetes mellitus and high risk. Pooled analyses of data from early studies and interim data from the CANagliflozin cardioVascular Assessment Study (CANVAS) suggested that canagliflozin might lead to increases in serum potassium, particularly the 300 mg dose in patients with renal impairment, which is important because high serum potassium is associated with increased cardiovascular and renal risk. We examined the effect of canagliflozin on serum potassium levels and hyperkalemia rates in the completed CANVAS Program. Methods: The CANVAS Program (n = 10,142) was comprised of two comparable double-blind, randomized, placebo-controlled trials (CANVAS and CANVAS-Renal). Participants received canagliflozin 100 or 300 mg or placebo. Serum potassium measurements were performed in a central laboratory0 and assessed at ∼6-month intervals. Results: In the CANVAS Program, mean potassium levels were generally consistent with canagliflozin and placebo, overall and by baseline estimated glomerular filtration rate (eGFR; ≥60, 45 to<60 and <45 mL/min/1.73 m2). The risk of increased or decreased potassium was similar with canagliflozin and placebo overall and by baseline eGFR (all P-heterogeneity ≥0.56) or use of renin-angiotensin-aldosterone system inhibitors (all P-heterogeneity ≥0.71); levels did not appear different by canagliflozin dose. Hyperkalemia {hazard ratio (HR) [95% confidence interval (CI)] 1.60 (0.92-2.81)} and serious hyperkalemia [HR (95% CI) 0.75 (0.27-2.11)] adverse events were not different across groups. Conclusions: In the CANVAS Program, there were no meaningful effects of canagliflozin on serum potassium in the overall population or key subgroups. Hyperkalemia adverse events were uncommon and occurred at comparable rates with canagliflozin and placebo

Impact of random variation in albuminuria and estimated glomerular filtration rate on patient enrolment and duration of clinical trials in nephrology

Aim To test whether a screening approach with more flexible urinary albumin creatinine ratio (UACR) and estimated glomerular filtration rate (eGFR) thresholds would decrease screen failure rate without negatively impacting on the event rate and overall study duration. Methods We performed a post-hoc analysis of the ALTITUDE trial. We selected participants randomized to placebo with a UACR of >300 mg/g and an eGFR between 30 mL/min/1.73 m(2) and 60 mL/min/1.73 m(2) at the first visit (pre-screening) for the trial. We then used less stringent lower UACR and higher eGFR thresholds for the following qualifying visit. For each scenario we calculated the number of eligible participants, the number of renal and cardiovascular endpoints, and the event rates. Based on this, we performed simulations for a future trial and estimated the duration of enrolment and total duration of this trial. Results The base scenario consisted of 848 participants (median UACR 1239 mg/g; median eGFR 44 mL/min/1.73 m(2)). Lowering the UACR and/or raising eGFR qualification thresholds increased the number of eligible participants, decreased screen failures and resulted in only a modest decrease in renal and cardiovascular event rates. For example, relaxing the UACR criterion from 300 mg/g to 210 mg/g at the qualifying visit, increased the number of eligible patients from 848 to 923, and increased the number of renal events from 117 to 122 events. The event rate showed a moderate decrease from 5.6 (4.6-6.7) events per 100 patient-years to 5.3 (4.4-6.4) events per 100 patient-years. In simulations, lowering the UACR and raising eGFR thresholds for inclusion accelerated patient enrolment and did not increase in the overall trial duration. Conclusion More flexible albuminuria and eGFR-based inclusion criteria, in participants who met the inclusion criteria of a trial based on pre-screening values prior to the clinical trial, decreases screen failure rates and accelerated patient enrolment leading to more efficient trial conduct without impacting the overall trial duration

EFFECTS OF THE MEDITERRANEAN DIET ON CARDIOVASCULAR OUTCOMES: A SYSTEMATIC REVIEW AND META-ANALYSIS

BACKGROUND: A Mediterranean dietary pattern is widely recommended for the prevention of chronic disease. We sought to define the most likely effects of the Mediterranean diet on vascular disease and mortality. METHODS: We searched MEDLINE, EMBASE and the Cochrane Central Register without language restriction for randomized controlled trials comparing Mediterranean to control diets. Data on study design, patient characteristics, interventions, follow-up duration, outcomes and adverse events were sought. Individual study relative risks (RR) were pooled to create summary estimates. RESULTS: Six studies with a total of 10950 participants were included. Effects on major vascular events (n = 477), death (n = 693) and vascular deaths (n = 315) were reported for 3, 5 and 4 studies respectively. For one large study (n = 1000) there were serious concerns about the integrity of the data. When data for all studies were combined there was evidence of protection against major vascular events (RR 0.63, 95% confidence interval 0.53-0.75), coronary events (0.65, 0.50-0.85), stroke (0.65, 0.48-0.88) and heart failure (0.30, 0.17-0.56) but not for all-cause mortality (1.00, 0.86-1.15) or cardiovascular mortality (0.90, 0.72-1.11). After the study of concern was excluded the benefit for vascular events (0.69, 0.55-0.86) and stroke (0.66, 0.48-0.92) persisted but apparently positive findings for coronary events (0.73, 0.51-1.05) and heart failure (0.25, 0.05-1.17) disappeared. CONCLUSION: The Mediterranean diet may protect against vascular disease. However, both the quantity and quality of the available evidence is limited and highly variable. Results must be interpreted with caution

Chronic kidney disease

Chronic kidney disease is a progressive disease with no cure and high morbidity and mortality that occurs commonly in the general adult population, especially in people with diabetes and hypertension. Preservation of kidney function can improve outcomes and can be achieved through non-pharmacological strategies (eg, dietary and lifestyle adjustments) and chronic kidney disease-targeted and kidney disease-specific pharmacological interventions. A plant-dominant, low-protein, and low-salt diet might help to mitigate glomerular hyperfiltration and preserve renal function for longer, possibly while also leading to favourable alterations in acid-base homoeostasis and in the gut microbiome. Pharmacotherapies that alter intrarenal haemodynamics (eg, renin-angiotensin-aldosterone pathway modulators and SGLT2 [SLC5A2] inhibitors) can preserve kidney function by reducing intraglomerular pressure independently of blood pressure and glucose control, whereas other novel agents (eg, non-steroidal mineralocorticoid receptor antagonists) might protect the kidney through anti-inflammatory or antifibrotic mechanisms. Some glomerular and cystic kidney diseases might benefit from disease-specific therapies. Managing chronic kidney disease-associated cardiovascular risk, minimising the risk of infection, and preventing acute kidney injury are crucial interventions for these patients, given the high burden of complications, associated morbidity and mortality, and the role of non-conventional risk factors in chronic kidney disease. When renal replacement therapy becomes inevitable, an incremental transition to dialysis can be considered and has been proposed to possibly preserve residual kidney function longer. There are similarities and distinctions between kidney-preserving care and supportive care. Additional studies of dietary and pharmacological interventions and development of innovative strategies are necessary to ensure optimal kidney-preserving care and to achieve greater longevity and better health-related quality of life for these patients