Febuxostat improves endothelial function in hemodialysis patients with hyperuricemia: A randomized controlled study

Effects of febuxostat on markers of endothelial dysfunction and renal progression in patients with chronic kidney disease

Hyperuricemia relates to chronic kidney disease (CKD) progression and impaired endothelial function. Febuxostat is potent and effective for decreasing serum uric acid levels. Information for the effect of febuxostat treatment on markers of endothelial dysfunction and renal injury among patients with CKD remains limited. A total of 84 patients with CKD stages III-IV with asymptomatic hyperuricemia were randomly assigned to either the febuxostat (40 mg/day, N = 42) or the matching control (N = 42) group for 8 weeks. Serum asymmetric dimethylarginine (ADMA), estimated glomerular filtration rate (eGFR), urine albumin, high sensitivity C-reactive protein (hs-CRP), ankle brachial index (ABI) and serum uric acid were measured at baseline and at the end of study. Febuxostat administration significantly reduced the serum uric acid concentration among patients with CKD when compared with control [- 3.40 (95% CI - 4.19 to - 2.62) vs. - 0.35 (95% CI - 0.76 to 0.06) mg/dL; P < 0.001, respectively). No significant difference in the changes in serum ADMA, hs-CRP, eGFR and albuminuria was identified between the two groups. Subgroup analysis among patients with decreased serum uric acid after febuxostat, the estimated GFR change between the febuxostat and the control group showed significant difference at 8 weeks (2.01 (95% CI 0.31 to 3.7) vs. 0.04 (95% CI - 1.52 to 1.61) mL/min/1.73 m2; P = 0.030, respectively). Adverse events specific to febuxostat were not observed. Febuxostat effectively reduced serum uric acid in the CKD population without improving endothelial dysfunction. It was able to preserve renal function in the subgroup of patients with CKD and lower serum uric acid level after treatment.Trial registration: Thai Clinical Trials, TCTR20210224005: 24/022021 http://www.thaiclinicaltrials.org/show/TCTR20210224005 .

Does uric acid-lowering treatment slow the progression of chronic kidney disease? A meta-analysis of randomized controlled trials

INTRODUCTION

Hyperuricemia has been proposed as an independent factor in the development and progression of chronic kidney disease (CKD). However, the effect of uric acid-lowering therapies on delaying CKD progression is still uncertain. Therefore, this systemic review aims to assess the effect of uric acid-lowering therapies on renal outcomes in pre-dialysis CKD patients.

METHODS

PubMed, Cochrane Library, and Lilacs databases were searched until April 24, 2021, for randomized clinical trials of CKD patients on uric acid-lowering treatment with xanthine-oxidase (XO) inhibitors. The weighted mean difference (WMD) or standard mean difference (SMD) with confidence interval (CI) were pooled using a random-effects model.

RESULTS

Among 567 studies found, eighteen met the inclusion criteria (n=2463 participants). Compared to the patient's control group, the WMD for the glomerular filtration ratio (GFR) and serum creatinine changes of the treated group was 2.02ml/min/1.73m² (95%CI 0.41 to 3.63, P=0.014) and -0.19mg/dl (95%CI -0.34 to -0.04, I²=86.2%, P=0.011), respectively. Subgroup analyses showed that the difference in follow-up time and CKD population type in the studies may explain the controversy about the role of uric acid-lowering therapies in CKD progression. The GFR and creatinine outcomes analysis by types of XO inhibitors showed no difference between the control and treated groups. Uric acid-lowering therapies were strongly associated with decreased serum uric acid and urinary protein-creatinine ratio and urinary albumin-creatinine ratio.

CONCLUSIONS

These findings suggest that uric acid-lowering treatment may slow CKD progress and reduce protein and albumin excretion. However, larger and properly powered randomized clinical trials with specific CKD populations are needed to confirm these findings.

Febuxostat Protects Human Aortic Valve Endothelial Cells From Oxidized Low-density Lipoprotein-Induced Injury and Monocyte Attachment

ABSTRACT

Atherosclerosis (AS) is a common cardiovascular disease with high morbidity and mortality. The pathogenesis of AS is closely related to endothelial dysfunction, which is mainly induced by oxidative stress, inflammation, and enhanced adhesion of monocytes to endothelial cells on the vessel wall. Febuxostat is a novel antigout agent recently reported to exert protective effects on endothelial dysfunction. This study aims to investigate the protective capacity of febuxostat against oxidized low-density lipoprotein (ox-LDL)-induced injury and monocyte attachment to endothelial cells. Human aortic valve endothelial cells (HAVECs) were stimulated with ox-LDL in the presence or absence of febuxostat (5 and 10 μM) for 6 hours. Mitochondrial reactive oxygen species were measured using MitoSox red staining, and the level of protein carbonyl was detected using enzyme-linked immunosorbent assay (ELISA). The expressions of IL-6, TNF-α, tissue factor (TF), VCAM-1, and ICAM-1 were evaluated with qRT-PCR assay and ELISA. Calcein-AM staining was used to determine the attachment of U937 monocytes to HAVECs. quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR) and Western blot were used to measure the expression level of early growth response 1 (Egr-1) in HAVECs. First, the elevated expression of LOX-1, activated oxidative stress, excessive secreted inflammatory factors, and promoted expression of TF induced by stimulation with ox-LDL were significantly reversed by febuxostat, indicating a protective effect of febuxostat against endothelial dysfunction. Second, the upregulated VCAM-1 and ICAM-1, as well as the increased proportion of adhered monocytes to HAVECs induced by ox-LDL, were significantly alleviated by febuxostat. Finally, the promoted expression level of Egr-1 induced by ox-LDL was pronouncedly suppressed by febuxostat. We conclude that febuxostat protected HAVECs from ox-LDL-induced injury and monocyte attachment.

Crosstalk between kidney and liver in non-alcoholic fatty liver disease: mechanisms and therapeutic approaches

Liver and kidney are vital organs that maintain homeostasis and injury to either of them triggers pathogenic pathways affecting the other. For example, non-alcoholic fatty liver disease (NAFLD) promotes the progression of chronic kidney disease (CKD), vice versa acute kidney injury (AKI) endorses the induction and progression of liver dysfunction. Progress in clinical and basic research suggest a role of excessive fructose intake, insulin resistance, inflammatory cytokines production, activation of the renin-angiotensin system, redox imbalance, and their impact on epigenetic regulation of gene expression in this context. Recent developments in experimental and clinical research have identified several biochemical and molecular pathways for AKI-liver interaction, including altered liver enzymes profile, metabolic acidosis, oxidative stress, activation of inflammatory and regulated cell death pathways. This review focuses on the current preclinical and clinical findings on kidney-liver crosstalk in NAFLD-CKD and AKI-liver dysfunction settings and highlights potential molecular mechanisms and therapeutic targets.

Efficacy and safety of urate-lowering agents in asymptomatic hyperuricemia: systematic review and network meta-analysis of randomized controlled trials

BACKGROUND

Asymptomatic hyperuricemia was found to be associated with increased cardiovascular disease risk but the potential benefits of urate-lowering therapy (ULT) remain controversial. We conducted a systematic review and network meta-analysis (NMA) with frequentist model to estimate the efficacy and safety of ULT in asymptomatic hyperuricemia.

METHODS

MEDLINE, Embase, and Scopus were searched without language restrictions. Randomized controlled trials (RCT) of adults with asymptomatic hyperuricemia were eligible if they compared any pair of ULTs (i.e., allopurinol, febuxostat, probenecid, benzbromarone, sulfinpyrazone, rasburicase, lesinurad, and topiroxostat) and placebo or no ULT, and had outcomes of interest, including composite renal events, major adverse cardiovascular events, serum urate levels, estimated glomerular filtration rate (eGFR), systolic blood pressure, and adverse events.

RESULTS

NMA with frequentist approach was applied to estimate relative treatment effects, i.e., risk ratio (RR) and mean difference (MD). A total of 23 RCTs were eligible. NMA identified beneficial effects of ULT on composite renal events and eGFR but not for other outcomes. Allopurinol and febuxostat had significantly lower composite renal events than placebo (RR 0.39, 95% confidence interval [CI] 0.23 to 0.66, and RR 0.68, 95% CI 0.46 to 0.99, respectively). Both treatments also resulted in significantly higher eGFR than placebo (MD 3.69 ml/min/1.73 m², 95% CI 1.31 to 6.08, and MD 2.89 ml/min/1.73 m², 95% CI 0.69 to 5.09, respectively). No evidence of inconsistency was identified.

CONCLUSIONS

Evidence suggests that allopurinol and febuxostat are the ULTs of choice in reducing composite renal events and improving renal function.

TRIAL REGISTRATION

This study was registered with PROSPERO: CRD42019145908. The date of the first registration was 12^th November 2019.

Long-Term Effect of Febuxostat on Endothelial Function in Patients With Asymptomatic Hyperuricemia: A Sub-Analysis of the PRIZE Study

Background

Xanthine oxidase is involved in the production of uric acid and the generation of superoxide anion. We evaluated the long-term effect of febuxostat, a non-purine selective xanthine oxidase inhibitor, on endothelial function in patients with asymptomatic hyperuricemia.

Methods

In the PRIZE study, patients with hyperuricemia were randomly assigned to either add-on febuxostat treatment (febuxostat group) or non-pharmacologic hyperuricemia treatment (control group). Among the 514 participants, endothelial function was assessed in 41 patients in the febuxostat group and 38 patients in the control group by flow-mediated vasodilation (FMD) of the brachial artery at the beginning of the study and after 12 and/or 24 months of treatment (63 men; median age, 68.0 years).

Results

The least squares mean concentration of serum uric acid was significantly lower in the febuxostat group than in the control group at 6 months (mean between-group difference [febuxostat group - control group], -2.09 mg/dL [95% confidence interval (CI), -2.520 to -1.659]; P < 0.001), 12 months (mean between-group difference, -2.28 mg/dL [95% CI, -2.709 to -1.842]; P < 0.001), and 24 months (mean between-group difference, -2.61 mg/dL [95% CI, -3.059 to -2.169]; P < 0.001). No significant differences were found between groups in the least squares mean estimated percentage change in FMD at 12 months (mean between-group difference, -0.56% [95% CI, -1.670 to 0.548]; P = 0.319) and at 24 months (mean between-group difference, -0.60% [95% CI, -1.886 to 0.685]; P = 0.357).

Conclusion

Febuxostat treatment did not alter endothelial function assessed by FMD during a 2-year study period in patients with asymptomatic hyperuricemia.

Serum Urate Levels of Hemodialyzed Renal Patients Revisited

OBJECTIVES

The need of maintaining serum urate (SU)-lowering agents in hemodialysis (HD) patients is an understudied area that requires a review, as it is a common practice. The aims were to assess the SU reduction achieved under HD and to analyze the kinetics of SU in a week of intermittent HD.

METHODS

The serum urate levels were determined before and after HD sessions in 96 consecutive patients with end-stage renal disease, and the average SU reduction was assessed. Variables related to HD were analyzed whether they were associated with SU reductions of 80% greater. In addition, a kinetics study was performed on 10 selected patients with hyperuricemia (SU before HD >6.8 mg/dL) throughout intermittent HD sessions in a 1-week period.

RESULTS

The mean ± SD age of the patients was 66.5 ± 13.8 years, and 62 of them were male (64.6%). The mean ± SD time on HD replacement was 7.1 ± 7.2 years, and 16 (16.4%) continued with urate-lowering agents. The mean SU reduction immediately after HD was 80.2% (95% confidence interval, 78.4-82.0); 51 patients (56.7%) showed SU reduction of 80% or greater. In the SU kinetics study, SU levels significantly reduced all over the period and persisted below hyperuricemia threshold (p = 0.015). Noteworthy, 6 patients (60%) were hyperuricemic before session 1, but only 1 (10%) before session 2 and none before session 3.

CONCLUSIONS

Under HD replacement therapy, the SU levels effectively reduced and persisted below saturation point, suggesting that the SU-lowering therapy would be unnecessary for patients on HD, but necessary in selected cases. The definition of hyperuricemia under HD needs to be revised.

Hyperuricemia, the heart, and the kidneys - to treat or not to treat?

Background

Hyperuricemia is a state in which the serum levels of uric acid are elevated. As such it has a pronounced effect on vascular and renal function with their consequences, while also showing some antioxidant effects that show to be beneficial.

Summary

Hyperuricemia has shown to have a J-shaped relationship with mortality, is frequently associated with development and progression of heart and kidney disease, and is correlated with malnutrition-inflammation-atherosclerosis syndrome, although several Mendelian studies have failed to show an association with morbidity and mortality. Hyperuricemia is usually associated with gout flares and tophi development but can also present as asymptomatic hyperuricemia. It is still uncertain whether asymptomatic hyperuricemia is an independent risk factor for cardiovascular or renal disease and as such its treatment is questionable.

Key messages

Some possible tools for future decision making are the use of noninvasive techniques such as pulse wave analysis, urinary sediment analysis, and joint ultrasound, which could help identify individuals with asymptomatic hyperuricemia that could benefit from urate lowering therapy most.

Comparing the Effects of Febuxostat and Allopurinol in an Animal Model of Metabolic Syndrome

INTRODUCTION

Recent studies highlighted the association of hyperuricemia and metabolic syndrome (MS). The aim of this study was to compare the beneficial effects of febuxostat versus allopurinol on the biochemical changes that occur in MS.

METHODS

Forty adult male Sprague Dawley albino rats were used in the study. Insulin resistance and MS were induced by administration of a high-fructose diet for 8 weeks. Follow-up of changes in weight, blood pressure, serum biochemical parameters, serum antioxidant catalase, and glutathione peroxidase activities was done. At the end of the study, animals were sacrificed, and the thoracic aorta was isolated for in vitro study of the endothelial integrity.

RESULTS

Allopurinol and febuxostat treatment induced significant reduction in body weight, systolic blood pressure, blood glucose, insulin, lipids, and improved kidney functions and endothelial integrity compared to nontreated rats. Febuxostat was more effective than allopurinol in normalizing serum fasting glucose, uric acid, catalase, and glutathione peroxidase activities.

CONCLUSION

Xanthine oxidase inhibitors ameliorated the effects of MS. Febuxostat was mildly superior to allopurinol in lowering serum fasting glucose, lipids, uric acid, and antioxidant enzyme activities.

Hyperuricemia in Kidney Disease: A Major Risk Factor for Cardiovascular Events, Vascular Calcification, and Renal Damage

Kidney disease, especially when it is associated with a reduction in estimated glomerular filtration rate, can be associated with an increase in serum urate (uric acid), suggesting that hyperuricemia in subjects with kidney disease may be a strictly secondary phenomenon. Mendelian randomization studies that evaluate genetic scores regulating serum urate also generally have not found evidence that serum urate is a causal risk factor in chronic kidney disease. Nevertheless, this is countered by a large number of epidemiologic, experimental, and clinical studies that have suggested a potentially important role for uric acid in kidney disease and cardiovascular disease. Here, we review the topic in detail. Overall, the studies strongly suggest that hyperuricemia does have an important pathogenic role that likely is driven by intracellular urate levels. An exception may be the role of extracellular uric acid in atherosclerosis and vascular calcification. One of the more striking findings on reviewing the literature is that the primary benefit of lowering serum urate in subjects with CKD is not by slowing the progression of renal disease, but rather by reducing the incidence of cardiovascular events and mortality. We recommend large-scale clinical trials to determine if there is a benefit in lowering serum urate in hyperuricemic subjects in acute and chronic kidney disease and in the reduction of cardiovascular morbidity and mortality in subjects with end-stage chronic kidney disease.

Randomized, Open-Label, Cross-Over Comparison of the Effects of Benzbromarone and Febuxostat on Endothelial Function in Patients with Hyperuricemia

Uric acid is generated with reactive oxygen species via xanthine oxidase (XO), and hyperuricemia, which is identified as the excess of uric acid in the blood, has been associated with vascular endothelial dysfunction. However, the effects of urate-lowering medicines on endothelial function have not been fully elucidated. Thus this study determined and compared the effects of benzbromarone (urate transporter 1 inhibitor) and febuxostat (XO inhibitor) on endothelial function.This randomized, cross-over, open-label study initially recruited 30 patients with hyperuricemia. They were divided into two groups, treated initially with benzbromarone or febuxostat for three months and then were switched for the next three months. Endothelial function was defined as reactive hyperemia indexes (RHI) determined using Endo-PAT 2000 before and at three and six months after medication using the two agents. Blood levels of asymmetric dimethylarginine (ADMA) and high-molecular-weight (HMW) adiponectin were also compared. We finally analyzed data from 24 patients whose endothelial function was assessed as described above.Our findings show that levels of uric acid significantly decreased, whereas those of HMW adiponectin and the RHI have significantly increased after treatment with benzbromarone. Meanwhile, in patients administered with febuxostat, uric acid levels tended to decrease and RHI significantly decreased. Neither of the two agents altered ADMA levels. The changes in RHI (P = 0.026) and HMW adiponectin levels (P = 0.001) were found to be significantly greater in patients treated with benzbromarone than febuxostat. Changes in the levels of HMW adiponectin and of uric acid were significantly correlated (r = -0.424, P = 0.039).Benzbromarone has increased adiponectin besides reducing uric acid levels, and thus, this might confer more benefits on endothelial function than febuxostat.

A randomized, double-blind, positive-controlled, prospective, dose-response clinical study to evaluate the efficacy and tolerability of an aqueous extract of Terminalia bellerica in lowering uric acid and creatinine levels in chronic kidney disease subjects with hyperuricemia

Background

Hyperuricemia is an independent risk factor in chronic kidney disease (CKD). Allopurinol and febuxostat are prescription medicines used to treat hyperuricemia but suffer side-effects. Earlier clinical study has shown that an aqueous extract of Terminalia bellerica (TBE), significantly reduced uric acid levels with no serious adverse effects in hyperuricemic subjects. The objective of this study is to determine the efficacy and tolerability of TB in reducing uric acid and creatinine levels in CKD subjects.

Methods

59-subjects were randomized to three groups-40 mg-once-daily febuxostat, 500 mg-twice-daily and 1000 mg-twice-daily of TBE. Serum uric acid, creatinine levels and estimated-glometular-filtration-rate were measured at baseline, 4, 8, 12, 16, 20, 24-weeks. Biomarkers of oxidative-stress, endothelial function, systemic inflammation, and platelet-aggregation were evaluated at baseline, 4, 8, 12, 24-weeks. Adverse drug reactions were recorded. Statistical analysis evaluated using GraphPadPrism4.

Results

55-subjects completed 24-week study. Starting at 4-weeks, all treatment groups showed a significant decrease in serum uric acid levels from baseline (p ≤ 0.0001). At 24-weeks, febuxostat, T.bellerica 500 mg-twice-daily, and T.bellerica 1000 mg-twice-daily doses decreased mean-percentage serum uric acid by 63.70 ± 4.62, 19.84 ± 6.43 and 33.88% ± 4.95% respectively (p ≤ 0.0001). Significant decrease in serum creatinine with all the groups starting at 16-weeks was seen (p ≤ 0.005-p ≤ 0.0001). At 24-weeks, the mean-percentage change in creatinine levels was 23.71 ± 12.50, 11.70 ± 9.0, and 24.42 ± 8.14, respectively with febuxostat, T.bellerica 500 mg-twice-daily and T.bellerica 1000 mg-twice-daily. Statistically significant (p ≤ 0.05) increase in estimated glomerular filtration rate-(eGFR) was seen at 20 (p ≤ 0.05) and 24-weeks (p ≤ 0.01) for both febuxostat vs T.bellerica 500 mg-twice-daily and T.bellerica 1000 mg-twice-daily vs T.bellerica 500 mg-twice-daily. There was no statistically significant difference between febuxostat and T.bellerica 1000 mg-twice-daily, with an increase of eGFR of 41.38 and 40.39 ml/min/1.73m² respectively, with the inference that T.bellerica at 1000 mg-twice-daily dose is as good as febuxostat 40 mg-once-daily. Positive improvements were made by all the groups in endothelial function and the related biomarkers and high-sensitivity C-reactive protein. None of the products showed effect on platelet aggregation.

Conclusion

In this 24-week study Febuxostat 40 mg, T. bellerica 500 mg-twice-daily and 1000 mg-twice-daily, significantly decreased the serum uric acid and creatinine levels, increased eGFR in CKD subjects. T. bellerica 500 mg-twice-daily and 1000 mg-twice-daily were one-third and more than half as effective at 24-weeks, respectively. T. bellerica extract may be considered a natural alternative for reducing serum uric acid levels.

Trial registration

This study was registered with the Clinical Trials Registry – India (CTRI) with the registration number: CTRI/2019/11/022093 [Registered on: 21/11/2019] Trial Registered Retrospectively.

Efficacy of febuxostat versus allopurinol and the predictors of achieving target serum urate in a cohort of Thai people with gout

OBJECTIVE

The objectives of our study were to compare the efficacy of febuxostat with allopurinol in Thai subjects with gout, as well as to determine the predictive factors of responsiveness to urate-lowering agents and to evaluate the safety of febuxostat in a real-world setting.

METHODS

The study was a retrospective cohort study; a total of 354 gout patients were recruited from February 2015 to November 2018. The patients were categorized according to prescription of allopurinol or febuxostat. Demographic data, comorbidities, concomitant medications, gout-related clinical parameters, and the laboratory results were collected. The serial serum urate (sUA) levels were recorded at the beginning of the treatment (baseline), and after treatment at 12 weeks, 18 weeks, and 27 weeks. The primary efficacy endpoint was the achievement of target urate of < 6 mg/dl in people taking febuxostat, compared with those taking allopurinol. The secondary endpoints were the predictive factors of achieving target urate level and adverse drug reactions in patients taking febuxostat. Multivariable regression analysis was used to determine factors associated with achieving target serum urate.

RESULTS

After the treatment, the febuxostat groups had significantly lower mean sUA compared with the allopurinol groups across all follow-up periods. The proportion of people who achieved target serum urate was also higher in the febuxostat groups compared with the allopurinol groups throughout the follow-up periods. The multivariable regression analysis showed that febuxostat 40 mg (OR = 10.96 (95% CI 4.32-27.80); p value < 0.001), febuxostat 80 mg (OR = 9.54 (95% CI 3.91-23.28), smoking (OR = 2.35 (95% CI 1.13-4.91); p value = 0.023), and low baseline serum urate (OR = 0.62 (95% CI 0.52-0.74); p value < 0.001) were associated with the achievement of target serum urate. No adverse drug reaction from febuxostat was observed even among people with renal insufficiency.

CONCLUSION

In a Thai cohort, people receiving febuxostat are more likely to achieve target serum urate level, compared with people receiving allopurinol. Febuxostat (40 or 80 mg), smoking, and low baseline serum urate were associated with the achievement of target serum urate.

KEY POINTS

• Febuxostat showed superior urate-lowering efficacy compared with allopurinol in an Asian population. • In addition to febuxostat, lower baseline serum urate level and history of smoking were associated with achieving target serum urate in gout patients.

Relationship between serum uric acid level and vascular injury markers in hemodialysis patients

PURPOSE

It has been reported that hyperuricemia causes vascular endothelial injury. Most hemodialysis patients present with hyperuricemia and also with vascular injury, resulting in cardiovascular diseases (CVD). However, the association of serum uric acid (sUA) with vascular injury markers in hemodialysis patients remains unclear. This study aimed to investigate this and discuss the mechanism by which uric acid causes vascular injury.

METHODS

We enrolled 48 Japanese maintenance hemodialysis patients without any history of CVD. The association between sUA level and three vascular injury markers (reactive hyperemia index [RHI], ankle-brachial index [ABI], and cardio ankle vascular index [CAVI]) was investigated by linear- and logistic regression analyses.

RESULTS

The median natural logarithm RHI (LnRHI) was 0.36. Linear regression analysis revealed a significant positive correlation between sUA level and LnRHI (β = 0.42, p = 0.001) in all patients. Moreover, a significant, strongly positive correlation was observed between sUA and LnRHI in patients who were treated with xanthine oxidase inhibitors (XOIs) (β = 0.75, p = 0.001). Further, the linear analysis showed a significant negative correlation between sUA level and CAVI in patients who were treated with XOIs (β = - 0.52, p = 0.049). sUA level was not significantly associated with ABI abnormality.

CONCLUSIONS

It is possible that a high level of sUA is significantly associated with better vascular endothelial function and condition of vascular tone in hemodialysis patients who were treated with XOIs. The findings suggest a significant paradox between sUA level and vascular endothelial function in hemodialysis patients; however, the opposite has been reported in patients without hemodialysis.

The effects of topiroxostat on vascular function in patients with hyperuricemia

Xanthine oxidoreductase (XOR) inhibitors, such as allopurinol and febuxostat, inhibit the catalysis of serum uric acid (SUA) synthesis. In doing so, they are thought to improve vascular endothelial function in patients with hyperuricemia and cardiovascular risk by reducing increases in SUA and reactive oxygen species levels. We performed a retrospective cohort study to evaluate the effects of topiroxostat, a novel XOR inhibitor, on vascular function measured by flow-mediated dilation (FMD) on ultrasonography. In total, 23 patients with hyperuricemia were enrolled. After approximately 8 weeks, topiroxostat was associated with a significant increase in the peak percentage change in diameter (∆FMD) from 4.53% ± 2.09% to 5.54% ± 3.08% (P = .045). It also significantly reduced the SUA levels from 7.31 ± 1.43 to 5.44 ± 1.11 mg/dL (P < .001). Although further studies are needed to validate these results, it appears that topiroxostat improves vascular endothelial function in patients with hyperuricemia.

Effects of febuxostat on renal function in patients with chronic kidney disease: A systematic review and meta-analysis

BACKGROUND/OBJECTIVE

Hyperuricemia has been proven to be an independent risk factor for chronic kidney disease (CKD). However, the role of hyperuricemia in the progression of CKD remains unclear. Thus, we performed a systematic review and meta-analysis to evaluate the efficacy and safety of febuxostat, a first line urate-lowering agent, in CKD patients with hyperuricemia.

METHODS

We have systematically searched for randomized controlled trials assessing the efficacy and safety of febuxostat versus control in CKD patients with hyperuricemia through MEDLINE, PubMed, EMBASE, and Cochrane databases. All statistical analyses were conducted by using the statistical package Review Manager, version 5.3.5. Heterogeneity was assessed using the Cochrane Q and I tests and summary statistics were reported with 95% confidence interval. Two-tailed test was used for analysis and a P value of <.05 is considered statistically significant.

RESULTS

Eleven eligible trials with 1317 participants were included in the meta-analysis. A significant reduction in serum uric acid was found in the febuxostat treated group. Also, a significant higher eGFR was found in the febuxostat treated group among CKD stage 3 and 4 patients. No significant difference of major complication or death was identified between treatment and control groups.

CONCLUSIONS

The meta-analysis showed that other than its urate-lowering effect, febuxostat presented a reno-protective effect in CKD patients. More studies with larger sample sizes and higher quality are required to clarify the role of febuxostat use in the progression of CKD.

Febuxostat and Cardiovascular Events: A Systematic Review and Meta-Analysis

BACKGROUND

Febuxostat is approved in the United States for the management of hyperuricemia in patients with gout. In November 2017 the FDA released a warning alert on a possible link between febuxostat and cardiovascular disease (CVD) reported in a single clinical trial.

OBJECTIVE

To conduct a systematic review and meta-analysis and assess the risk of major adverse cardiovascular events (MACE) in patients receiving febuxostat compared to a control group.

METHODS

We searched the MEDLINE and EMBASE database for studies published up until March 2018. We included randomized clinical trials (RCTs) that compared febuxostat to control groups including placebo and allopurinol. We calculated the pooled relative risk (RR) of MACE and cardiovascular disease (CVD) mortality with the corresponding 95% confidence intervals (CI).

RESULTS

Our search yielded 374 potentially relevant studies. Among the 25 RCTs included in the systematic review, 10 qualified for the meta-analysis. Among the 14,402 subjects included, the median age was 54 years (IQR 52-67) and 90% were male (IQR 82-96); 8602 received febuxostat, 5118 allopurinol, and 643 placebo. The pooled RR of MACE for febuxostat was 0.9; 95% CI 0.6-1.5 (p= 0.96) compared to the control. The RR of CV-related death for febuxostat was 1.29; 95% CI 1.01-1.66 (p=0.03).

CONCLUSIONS

Compared with other SU-lowering treatments, febuxostat does not increase or decrease the risk of cardiovascular disease but may increase the risk of CVD death. More RCTs measuring cardiovascular safety as a primary outcome are needed to adequately evaluate the risk of CVD with febuxostat.

Dissociation between urate and blood pressure in mice and in people with early Parkinson's disease

Background

Epidemiological, laboratory and clinical studies have established an association between elevated urate and high blood pressure (BP). However, the inference of causality remains controversial. A naturally occurring antioxidant, urate may also be neuroprotective, and urate-elevating treatment with its precursor inosine is currently under clinical development as a potential disease-modifying strategy for Parkinson's disease (PD).

Methods

Our study takes advantage of a recently completed phase II trial evaluating oral inosine in de novo non-disabling early PD with no major cardiovascular and nephrological conditions, and of three lines of genetically engineered mice: urate oxidase (UOx) global knockout (gKO), conditional KO (cKO), and transgenic (Tg) mice with markedly elevated, mildly elevated, and substantially reduced serum urate, respectively, to systematically investigate effects of urate-modifying manipulation on BP.

Findings

Among clinical trial participants, change in serum urate but not changes in systolic, diastolic and orthostatic BP differed by treatment group. There was no positive correlation between urate elevations and changes in systolic, diastolic and orthostatic BP ((p = .05 (in inverse direction), 0.30 and 0.63, respectively)). Between UOx gKO, cKO, or Tg mice and their respective wildtype littermates there were no significant differences in systolic or diastolic BP or in their responses to BP-regulating interventions.

Interpretation

Our complementary preclinical and human studies of urate modulation in animal models and in generally healthy early PD do not support a hypertensive effect of urate elevation or an association between urate and BP.

Fund

U.S. Department of Defense, RJG Foundation, Michael J. Fox Foundation LEAPS program, National Institutes of Health, American Federation for Aging Research, Parkinson's Disease Foundation Advancing Parkinson's Therapies initiative.

Efficacy and safety of febuxostat for treating hyperuricemia in patients with chronic kidney disease and in renal transplant recipients: A systematic review and meta-analysis

Febuxostat is potent and well-tolerated in the management of chronic gout. However, its clinical efficacy and safety in the treatment of hyperuricemia in patients with chronic kidney disease (CKD) and in renal transplant recipients have remained to be fully determined. The MEDLINE, EMBASE and Cochrane Library databases were searched for relevant articles. Data were extracted and pooled results were estimated from the standard mean difference (SMD) with 95% confidence intervals (95% CIs). The quality of the studies included was assessed, and their publication bias was examined. Four prospective randomized controlled trials and two retrospective observational studies were included in the systematic review and meta-analysis. Febuxostat administration significantly reduced the serum uric acid concentration in patients with CKD and in renal transplant recipients when compared with allopurinol or placebo in the short-term (1 month: SMD, −2.24; 95% CI, −3.59 to −0.89; P-value of SMD=0.001; I², 92.4%; 3 months: SMD, −1.20; 95% CI, −2.04 to −0.36; P-value of SMD=0.005; I², 88.9%; 6 months: SMD, −1.49; 95% CI, −2.68 to −0.30; P-value of SMD=0.014; I², 92.9%). Furthermore, the increase in the estimated glomerular filtration rate in the febuxostat group was significantly higher than that in the control group (SMD, 0.30; 95% CI, 0.031 to 0.58; P-value of SMD=0.029; I², 0.0%). No significant difference in the changes in serum creatinine (Scr), low-density lipoprotein (LDL) and high-density lipoprotein (HDL) was identified between the two groups (Scr: SMD, −0.17; 95% CI, −0.97 to 0.63; P-value of SMD=0.67; I², 79.2%; LDL: SMD, −0.21; 95% CI, −0.49 to 0.07; P-value of SMD=0.13; I², 34.1%; HDL: SMD, −0.05; 95% CI, −0.70 to 0.61; P-value of SMD=0.89; I², 69.2%). In conclusion, febuxostat is a potent and well-tolerated agent for the short-term management of hyperuricemia in patients with CKD and in renal transplant recipients. However, these data should be interpreted with caution due to the varied design of the studies included in the present meta-analysis.

Efficacy and safety of febuxostat extended release and immediate release in patients with gout and moderate renal impairment: phase II placebo-controlled study

BACKGROUND

Febuxostat immediate release (IR), a xanthine oxidase inhibitor, is indicated for the management of hyperuricemia in patients with gout by lowering urate levels. An extended release (XR) formulation of febuxostat was developed to provide equal or superior efficacy on urate lowering compared with the IR formulation and potentially lower the risk of treatment-initiated gout flares due to an altered pattern of drug exposure. The present study evaluated the efficacy and safety of febuxostat XR and IR formulations in patients with gout and moderate renal impairment (estimated glomerular filtrate rate ≥ 30 and < 60 ml/min).

METHODS

This was an exploratory, 3-month, phase II, multicenter, placebo-controlled, double-blind proof-of-concept study. Patients (n = 189) were randomized 1:1:1:1:1 to receive placebo or febuxostat IR 40 mg, XR 40 mg, IR 80 mg, or XR 80 mg once daily. Endpoints included: proportion of patients with serum uric acid (sUA) < 5.0 mg/dl at month 3 (primary endpoint), proportion of patients with sUA < 6.0 mg/dl at month 3, and proportion of patients with ≥ 1 gout flare requiring treatment over 3 months.

RESULTS

At month 3, all febuxostat treatment groups were associated with greater proportions of patients achieving sUA < 5.0 mg/dl (p < 0.05 vs placebo). A greater proportion of patients receiving XR 40 mg achieved sUA < 5.0 mg/dl versus those receiving IR 40 mg (p = 0.034); proportions were similar in the IR 80 mg and XR 80 mg groups. Higher proportions of febuxostat-treated patients achieved sUA < 6.0 mg/dl at month 3 (p < 0.05 vs placebo) and experienced ≥ 1 gout flare (significant for all comparisons, except XR 40 mg). Incidences of treatment-related adverse events were low across all treatment groups; the majority were mild or moderate with no apparent trends correlating with IR or XR doses. The most common treatment-emergent adverse event was hypertension. One death (unrelated to the study drug) was reported.

CONCLUSIONS

These exploratory data demonstrate that febuxostat (XR and IR) formulations were effective and well tolerated in patients with gout and moderate renal impairment.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT02128490 Registered on 29 April 2014.

Xanthine oxidase inhibitors for prevention of cardiovascular events: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Xanthine oxidase inhibitors (XOI), classified as purine-like (allopurinol and oxypurinol) and non-purine (febuxostat and topiroxostat) XOI, present antioxidant properties by reducing the production of reactive oxygen species derived from purine metabolism. Oxidative stress is an important factor related to endothelial dysfunction and ischemia-reperfusion injury, and may be implicated in the pathogenesis of heart failure, hypertension, and ischemic heart disease. However, there is contradictory evidence regarding the possible cardiovascular (CV) protective effect exerted by XOI. Our objective is to compare the incidence of major adverse cardiovascular events (MACE), mortality, total (TCE) and specific CV events in randomized controlled trials (RCTs) testing XOI against placebo or no treatment.

METHODS

PubMed, EMBASE, Web of Science, Cochrane Central, Lilacs databases were searched from inception to Dec 30 2016, along with hand searching. RCTs including exclusively adult individuals, lasting ≥ 4 weeks, with no language restriction, were eligible. Independent paired researchers selected studies and extracted data. Considering the expected rarity of events, Peto and DerSimonian/Laird odds ratios (OR), the latter in case of heterogeneity, were used for analysis. Random-effects meta-regression was used to explore heterogeneity.

RESULTS

The analysis of MACE included 81 articles (10,684 patients, 6434 patient-years). XOI did not significantly reduce risk of MACE (ORP = 0.71, 95% CI 0.46-1.09) and death (0.89, 0.59-1.33), but reduced risk of TCE (0.60, 0.44-0.82; serious TCE: 0.64, 0.46 to 0.89), and hypertension (0.54, 0.37 to 0.80). There was protection for MACE in patients with previous ischemic events (0.42, 0.23-0.76). Allopurinol protected for myocardial infarction (0.38, 0.17-0.83), hypertension (0.32, 0.18-0.58), TCE (0.48, 0.31 to 0.75, I2 = 55%) and serious TCE (0.56, 0.36 to 0.86, I2 = 44%). Meta-regression associated increasing dose of allopurinol with higher risk of TCE and serious TCE (P < 0.05). Accordingly, lower doses (≤ 300 mg/day) of allopurinol reduced the risk of TCE, unlike higher doses. Non-purine-like XOI did not significantly reduce or increase the risk of adverse CV events, but confidence intervals were wide. Quality of evidence was generally low to moderate.

CONCLUSIONS

Purine-like XOI may reduce the incidence of adverse CV outcomes. However, higher doses of allopurinol (> 300 mg/day) may be associated with loss of CV protection.

Effect of Febuxostat on the Endothelial Dysfunction in Hemodialysis Patients: A Randomized, Placebo-Controlled, Double-Blinded Study

BACKGROUND

Endothelial dysfunction is an important risk factor for cardiovascular diseases to occur in end-stage renal disease patients. Febuxostat, being a novel xanthine oxidase inhibitor, is apparently having a beneficial role in improving the endothelial dysfunction; however, data among hemodialysis patients are still limited.

METHODS

A prospective, placebo-controlled, block-randomized, double-blinded study was carried out to evaluate the effect of oral febuxostat on the endothelial dysfunction in hemodialysis patients. Fifty-seven eligible hemodialysis patients were randomly assigned to either the drug group (40 mg thrice weekly) or the placebo group. Serum Asymmetric dimethylarginine (ADMA), Serum uric acid (UA), and serum high sensitivity C-reactive protein (hsCRP) were measured at baseline and at the end of a 2-month study. Serum alanine aminotransferase (ALT), serum aspartate aminotransferase (AST), and the occurrence of pancytopenia were tested as safety parameters at baseline and at the end of study.

RESULTS

Serum UA significantly decreased from 7.5 ± 0.8 to 5.1 ± 1.2 mg/dL in the febuxostat group, while it did not change significantly in the placebo group. Treatment with febuxostat resulted in a significant decrease in the serum ADMA level from 1.027 ± 0.116 to 0.944 ± 0.104 µmol/L and the serum hsCRP level from 12.5 ± 1.65 to 12.1 ± 1.70 mg/L. Testing of serum ALT, serum AST, and pancytopenia revealed no significant difference in both groups.

CONCLUSION

Febuxostat appears to improve hyperuricemia and endothelial dysfunction and ameliorate inflammation in hemodialysis patients with no safety concerns.

Febuxostat-induced agranulocytosis in an end-stage renal disease patient: A case report

INTRODUCTION

Febuxostat, a nonpurine xanthine oxidase inhibitor, is approved as the first-line urate-lowering therapy in gout patients with normal renal function or mild to moderate renal impairment. The most common adverse effects of febuxostat are liver function test abnormalities, diarrhea, and skin rash. However, there is insufficient data in patients with severe renal impairment and end-stage renal disease (ESRD). We report the first case, to our knowledge, in which agranulocytosis developed after febuxostat treatment in an ESRD patient.

CLINICAL PRESENTATION

A 67-year-old woman with gout and ESRD received febuxostat 40 mg a day for 2.5 months. She subsequently complicated with febrile neutropenia and the absolute neutrophil count was only 14/μL. After broad-spectrum antibiotics treatment and no more exposure to febuxostat for 17 days, her infection and neutrophil count recovered. Bone marrow study during neutropenic period showed myeloid hypoplasia without evidence of hematologic neoplasms.

CONCLUSION

As febuxostat use may become more common in the population of advanced renal failure, clinicians should be aware of this rare but potentially life-threatening adverse effect. Based on our experience, close monitoring hemogram and immediate discontinuation of this medication may prevent serious consequences.

Emerging Liver-Kidney Interactions in Nonalcoholic Fatty Liver Disease

Mounting evidence connects non-alcoholic fatty liver disease (NAFLD) to chronic kidney disease (CKD). We review emerging mechanistic links between NAFLD and CKD, including altered activation of angiotensin converting enzyme (ACE)-2, nutrient/energy sensors sirtuin-1 and AMP-activated kinase, as well as impaired antioxidant defense mediated by nuclear factor erythroid 2-related factor-2 (Nrf2). Dietary fructose excess may also contribute to NAFLD and CKD. NAFLD affects renal injury through lipoprotein dysmetabolism and altered secretion of the hepatokines fibroblast growth factor-21, fetuin-A, insulin-like growth factor-1, and syndecan-1. CKD may mutually aggravate NAFLD and associated metabolic disturbances through altered intestinal barrier function and microbiota composition, the accumulation of uremic toxic metabolites, and alterations in pre-receptor glucocorticoid metabolism. We conclude by discussing the implications of these findings for the treatment of NAFLD and CKD.

New Pathogenic Concepts and Therapeutic Approaches to Oxidative Stress in Chronic Kidney Disease

In chronic kidney disease inflammatory processes and stimulation of immune cells result in overproduction of free radicals. In combination with a reduced antioxidant capacity this causes oxidative stress. This review focuses on current pathogenic concepts of oxidative stress for the decline of kidney function and development of cardiovascular complications. We discuss the impact of mitochondrial alterations and dysfunction, a pathogenic role for hyperuricemia, and disturbances of vitamin D metabolism and signal transduction. Recent antioxidant therapy options including the use of vitamin D and pharmacologic therapies for hyperuricemia are discussed. Finally, we review some new therapy options in diabetic nephropathy including antidiabetic agents (noninsulin dependent), plant antioxidants, and food components as alternative antioxidant therapies.