An allopurinol-controlled, multicenter, randomized, open-label, parallel between-group, comparative study of febuxostat (TMX-67), a non-purine-selective inhibitor of xanthine oxidase, in patients with hyperuricemia including those with gout in Japan: phase 2 exploratory clinical study

Effectiveness and safety of different doses of febuxostat compared with allopurinol in the treatment of hyperuricemia: a meta-analysis of randomized controlled trials

BACKGROUND

The prevalence of hyperuricemia has increased steadily with the continuous improvement of living standards. Some studies have reported the clinical effectiveness and safety of different doses of febuxostat in comparison with allopurinol in hyperuricemia treatment, but the sample sizes of the studies have been small, and the results have been inconsistent. We designed this meta-analysis to evaluate the effectiveness and safety of different doses of febuxostat compared with allopurinol in the treatment of hyperuricemia.

METHODS

The Cochrane Library, Embase, PubMed, Web of Science and ClinicalTrials.gov databases were searched to identify randomized controlled trials (RCTs) comparing the use of febuxostat and allopurinol for the treatment of hyperuricemia. The effectiveness and safety of different doses of febuxostat and allopurinol in treating hyperuricemia were assessed using meta-analysis.

RESULTS

A total of 11 randomized controlled trials were included in the meta-analysis. The results of the meta-analysis showed that the percentage of patients achieving serum uric acid levels of 6.0 mg/dL or less was higher among patients taking febuxostat (80 mg/d) than among patients taking allopurinol (200-300 mg/d) [RR = 1.79, 95% CI (1.55, 2.08), P < 0.00001]. However, there was no statistically significant difference in the percentage of patients achieving serum uric acid levels of 6.0 mg/dL or less between febuxostat (40 mg/d) and allopurinol (200-300 mg/d) [RR = 1.10, 95% CI (0.93, 1.31), P = 0.25]. There was also no statistically significant difference in the incidence of gout between the febuxostat (40 mg/d) and allopurinol (200-300 mg/d) [RR = 0.97, 95% CI (0.64, 1.49), P = 0.91] or between the febuxostat (80 mg/d) and allopurinol (200-300 mg/d) [RR = 1.13, 95% CI (0.81, 1.58), P = 0.48].No significant difference in the incidence of major adverse reactions as observed between the febuxostat (40 mg/d) and allopurinol (200-300 mg/d) [RR = 1.16; 95% CI (0.43, 3.16), P = 0.77] or between the febuxostat (80 mg/d) and allopurinol (200-300 mg/d) [RR = 1.06; 95% CI (0.79, 1.42), P = 0.70]. The incidence of adverse cardiovascular events did not differ significantly between the febuxostat (40 mg/d) and allopurinol (200-300 mg/d) [RR = 1.30; 95% CI (0.57, 2.95), P = 0.53] or between the febuxostat (80 mg/d) and allopurinol (200-300 mg/d) [RR = 1.79; 95% CI (0.74, 4.32), P = 0.20].

CONCLUSIONS

Febuxostat (80 mg/d) was associated with a higher percentage of patients achieving serum uric acid levels of 6.0 mg/dL or less than allopurinol (200-300 mg/d), however, febuxostat (80 mg/d) did not exhibit better efficacy in reducing the incidence of gout. More attention should be devoted to the adverse reactions caused by an increase in febuxostat doses.

Association between use of febuxostat and muscle injury: A disproportionality analysis and meta-analysis of randomized controlled trials

AIMS

Several reports have suggested an association between febuxostat and muscle injury. The purpose of this study was to determine whether febuxostat increases the risk of muscle injury. This study included an analysis of the US Food and Drug Administration Adverse Event Reporting System (FAERS) database and a systematic review/meta-analysis of randomized controlled trials.

METHODS

First, evaluation of the FAERS data included a disproportionality analysis that compared patients with and without rhabdomyolysis according to whether they were receiving febuxostat or allopurinol. Second, a systematic review/meta-analysis was performed to assess the risk of rhabdomyolysis and muscle injury in patients who used febuxostat or allopurinol.

RESULTS

Analysis of the FAERS data revealed disproportionality for increasing rhabdomyolysis in patients who received febuxostat (reporting odds ratio 4.49, 95% confidence interval [CI] 3.72-5.38, P < .01) and allopurinol (reporting odds ratio 2.49, 95% CI 2.25-2.75, P < .01). Nineteen studies were eligible for inclusion in the systematic review/meta-analysis. Rhabdomyolysis was reported in only 1 study. The risk of any type of muscle damage was not significantly increased with febuxostat compared with placebo (risk ratio 0.92, 95% CI 0.73-1.17, P = .52, I²  = 0%; 8 studies including 2597 participants, high-certainty evidence) or allopurinol (risk ratio 1.03, 95% CI 0.94-1.11, P = .56, I²  = 0%; 9 studies including 17 644 participants, moderate-certainty evidence).

CONCLUSION

Febuxostat does not seem to affect the risk of muscle injury. However, the findings of this meta-analysis indicate a need for further high-quality observational studies with long-term follow-up.

Xanthine Oxidoreductase Inhibitors Suppress the Onset of Exercise-Induced AKI in High HPRT Activity Urat1-Uox Double Knockout Mice

BACKGROUND

Hereditary renal hypouricemia type 1 (RHUC1) is caused by URAT1/SLC22A12 dysfunction, resulting in urolithiasis and exercise-induced AKI (EIAKI). However, because there is no useful experimental RHUC1 animal model, the precise pathophysiologic mechanisms underlying EIAKI have yet to be elucidated. We established a high HPRT activity Urat1-Uox double knockout (DKO) mouse as a novel RHUC1 animal model for investigating the cause of EIAKI and the potential therapeutic effect of xanthine oxidoreductase inhibitors (XOIs).

METHODS

The novel Urat1-Uox DKO mice were used in a forced swimming test as loading exercise to explore the onset mechanism of EIAKI and evaluate related purine metabolism and renal injury parameters.

RESULTS

Urat1-Uox DKO mice had uricosuric effects and elevated levels of plasma creatinine and BUN as renal injury markers, and decreased creatinine clearance observed in a forced swimming test. In addition, Urat1-Uox DKO mice had increased NLRP3 inflammasome activity and downregulated levels of Na⁺-K⁺-ATPase protein in the kidney, as Western blot analysis showed. Finally, we demonstrated that topiroxostat and allopurinol, XOIs, improved renal injury and functional parameters of EIAKI.

CONCLUSIONS

Urat1-Uox DKO mice are a useful experimental animal model for human RHUC1. The pathogenic mechanism of EIAKI was found to be due to increased levels of IL-1β via NLRP3 inflammasome signaling and Na⁺-K⁺-ATPase dysfunction associated with excessive urinary urate excretion. In addition, XOIs appear to be a promising therapeutic agent for the treatment of EIAKI.

The association between urate-lowering therapies and treatment-related adverse events, liver damage, and major adverse cardiovascular events (MACE): A network meta-analysis of randomized trials

PURPOSE

Hyperuricemia is a common disease that may lead to gout, renal damage, and cardiovascular events. Oral medication is the main treatment for hyperuricemia patients when lifestyle intervention fails. An evaluation of the safety of various urate-lowering therapies (ULTs) is integral to clinical decision-making. We constructed a network meta-analysis (NMA) to evaluate the safety of oral ULTs.

METHODS

MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials were searched up to April 1, 2021, for randomized controlled trials that examined the safety of ULTs. The language restriction was English. The three outcomes used to assess the safety of uric acid lowering medications were treatment-related adverse events, liver damage, and major adverse cardiovascular events (MACE).

RESULTS

Thirty-two trials enrolling 23,868 individuals were included in the study. In terms of treatment-related adverse events, there were no statistically significant differences between five uric acid lowering medications and placebo: allopurinol (risk ratio (RR): 1.08; 95% credible interval (CrI): 0.91, 1.29), febuxostat (RR: 1.05; 95% CrI: 0.89, 1.25), lesinurad (RR: 1.19; 95% CrI: 0.85, 1.67), lesinurad combined with xanthine oxidase inhibitor (XOI, RR: 1.05; 95% CrI: 0.83, 1.32), and topiroxostat (RR: 1.01; 95% CrI: 0.83, 1.23). Topiroxostat likely increases risk of liver damage (RR: 2.65; 95%CI: 1.24, 5.70; NNH: 33.40) as compared with placebo. With regard to MACE, there were no statistically significant differences between three uric acid lowering medications and placebo: allopurinol (RR: 0.63; 95% CrI: 0.36, 1.34), febuxostat (RR: 0.69; 95% CrI: 0.38, 1.66), and lesinurad combined with XOI (RR: 0.56; 95% CrI: 0.23, 1.85). The rankings of different interventions were depicted by cumulative ranking curve (SUCRA).

CONCLUSIONS

Through NMA, we provide some evidence for the safety of ULTs. We found no statistically significant differences in their effects on treatment-related adverse events and MACE. However, topiroxostat likely increases the risk of liver damage.

Cardiovascular safety of febuxostat compared to allopurinol for the treatment of gout: A systematic and meta-analysis

The cardiovascular safety of febuxostat compared to allopurinol for the treatment of gout remains equivocal. Febuxostat had a better safety outcome compared with allopurinol. In this systematic review and meta-analysis, we searched MEDLINE and Embase for articles published between March 1, 2000 and April 4, 2021, without any language restrictions. We did a systematic review and meta-analysis of included clinical trials to evaluate the cardiovascular safety of febuxostat compared to allopurinol for treatment of chronic gout. Two reviewers independently selected studies, assessed study quality, and extracted data. Risk ratios were calculated with random effects and were reported with corresponding 95% confidence intervals (CI). From 240 potentially relevant citations, 224 papers were excluded; 16 studies were ultimately included in the analysis. Febuxostat had a better safety outcome compared with allopurinol，which was the composite of urgent coronary revascularization (OR: 0.84, 95% CI: 0.77-0.90, p < .0001) and stroke (OR: 0.87, 95% CI: 0.79-0.97, p = .009). However, that difference was not found in nonfatal myocardial infarction (OR: 0.99, 95% CI: 0.80-1.22, p = .91), cardiovascular related mortality (OR: 0.98, 95% CI: 0.69-1.38, p = .89) and all-cause mortality (OR: 0.93, 95% CI: 0.75-1.15, p = .52). No significant differences in cardiovascular related mortality and all-cause mortality were observed across any subgroup. This meta-analysis adds new evidence regarding the cardiovascular safety of febuxostat in patients. Initiation of febuxostat in patients was not associated with an increased risk of death or serious cardiovascular related adverse events compared with allopurinol.

Febuxostat for Cerebral and CaRdiorenovascular Events PrEvEntion StuDy

Aims

To compare the occurrence of cerebral, cardiovascular, and renal events in patients with hyperuricaemia treated with febuxostat and those treated with conventional therapy with lifestyle modification.

Methods and results

This multicentre, prospective, randomized open-label, blinded endpoint study was done in 141 hospitals in Japan. A total of 1070 patients were included in the intention-to-treat population. Elderly patients with hyperuricaemia (serum uric acid >7.0 to ≤9.0 mg/dL) at risk for cerebral, cardiovascular, or renal disease, defined by the presence of hypertension, Type 2 diabetes, renal disease, or history of cerebral or cardiovascular disease, were randomized to febuxostat and non-febuxostat groups and were observed for 36 months. Cerebral, cardiovascular, and renal events and all deaths were defined as the primary composite event. The serum uric acid level at endpoint (withdrawal or completion of the study) in the febuxostat (n = 537) and non-febuxostat groups (n = 533) was 4.50 ± 1.52 and 6.76 ± 1.45 mg/dL, respectively (P < 0.001). The primary composite event rate was significantly lower in the febuxostat group than in non-febuxostat treatment [hazard ratio (HR) 0.750, 95% confidence interval (CI) 0.592–0.950; P = 0.017] and the most frequent event was renal impairment (febuxostat group: 16.2%, non-febuxostat group: 20.5%; HR 0.745, 95% CI 0.562–0.987; P = 0.041).

Conclusion

Febuxostat lowers uric acid and delays the progression of renal dysfunction.

Registration

ClinicalTrials.gov (NCT01984749).

Perfecting a high hypoxanthine phosphoribosyltransferase activity-uricase KO mice to test the effects of purine- and non-purine-type xanthine dehydrogenase (XDH) inhibitors

BACKGROUND AND PURPOSE

Purine metabolism in mice and human differ in terms of uricase (Uox) activity as well as hypoxanthine phosphoribosyltransferase (HPRT) activity. The aim of this study was the establishment of high HPRT activity-Uox knockout (KO) mice as a novel hyperuricaemic model. Then to investigate the effects of purine-type xanthine dehydrogenase (XDH) inhibitor, allopurinol, and non-purine-type XDH inhibitor, topiroxostat, on purine metabolism.

EXPERIMENTAL APPROACH

A novel hyperuricaemic mouse model was established by mating B6-ChrXCMSM mice with uricase KO mice. The pharmacological effects of allopurinol and topiroxostat were explored by evaluating urate, hypoxanthine, xanthine and creatinine in the plasma and urine of these model mice. Furthermore, we analysed the effect of both drugs on erythrocyte hypoxanthine phosphoribosyltransferase activity.

KEY RESULTS

Plasma urate level and urinary urate/creatinine ratio significantly decreased after administration of allopurinol 30 mg·kg-1 or topiroxostat 1 mg·kg-1 for 7 days. The urate-lowering effect was equivalent for allopurinol and topiroxostat. However, the urinary hypoxanthine/creatinine ratio and xanthine/creatinine ratio after treatment with topiroxostat were significantly lower than for allopurinol. In addition, the urinary oxypurine/creatinine ratio was significantly lowered after treatment with topiroxostat, but allopurinol elicited no such effect. Furthermore, allopurinol inhibited mouse erythrocyte hypoxanthine phosphoribosyltransferase, while topiroxostat did not.

CONCLUSIONS AND IMPLICATIONS

High hypoxanthine phosphoribosyltransferase activity- uricase KO mice were established as a novel hyperuricaemic animal model. In addition, topiroxostat, a non-purine-type xanthine dehydrogenase inhibitor, elicited a potent plasma urate-lowering effect. However, unlike allopurinol, topiroxostat did not perturb the salvage pathway, resulting in lowered total oxypurine excretion.

A Randomized, Double-Blind, Non-Inferiority Study of Febuxostat Versus Allopurinol in Hyperuricemic Chinese Subjects With or Without Gout

Introduction

This 24-week randomized, double-blind, non-inferiority study compared the efficacy and safety of febuxostat, a xanthine oxidase inhibitor, with allopurinol using an up-titration method in hyperuricemic Chinese subjects with or without gout.

Methods

Eligible adults (serum uric acid [SUA] > 7.0 mg/dl with a history of gout, SUA ≥ 8.0 mg/dl with complications or SUA ≥ 9.0 mg/dl without complications) were randomized (1:1:1) to febuxostat 40 mg/day, 80 mg/day, or allopurinol 300 mg/day. Starting doses of febuxostat 20 mg/day and allopurinol 100 mg/day were up-titrated, up to 16 weeks, to the randomized doses and maintained to week 24. Primary endpoint was non-inferiority of febuxostat 40 mg/day versus allopurinol 300 mg/day based on the percentage of subjects with SUA ≤ 6.0 mg/dl at week 24. The same comparison was made between febuxostat 60 mg/day or 80 mg/day versus allopurinol 300 mg/day. Safety assessments included measurement of treatment-emergent adverse events (TEAEs).

Results

The per-protocol population comprised 472 subjects. Non-inferiority of febuxostat 40 mg/day versus allopurinol 300 mg/day was not demonstrated based on the protocol-defined margin of − 10% (44.7 vs. 50.0%; − 5.3% difference; 95% confidence interval [CI]: − 16.4%, 5.8%); however, superiority over allopurinol 300 mg/day was demonstrated for febuxostat 60 mg/day at week 16 (66.3 vs. 51.2%; a 15.0% difference; 95% CI: 4.2%, 25.9%) and febuxostat 80 mg/day at week 24 (70.0 vs. 50.0%; a 20.0% difference; 95% CI: 9.3%, 30.7%). The frequency of TEAEs was similar across groups, with gout flares occurring frequently.

Conclusions

Using a novel dose-titration method, although the primary endpoint of non-inferiority of febuxostat 40 mg/day versus allopurinol 300 mg/day was not reached, non-inferiority and superiority of febuxostat 60 mg/day and 80 mg/day versus allopurinol 300 mg/day was demonstrated at weeks 16 and 24, respectively. Febuxostat demonstrated an acceptable tolerability profile in the treatment of hyperuricemia in Chinese subjects with or without gout.

Trial Registration

JapicCTI-132106.

Funding

Astellas Pharma Global Development, Inc.

Electronic Supplementary Material

The online version of this article (10.1007/s40744-019-00173-8) contains supplementary material, which is available to authorized users.

Baseline urate level and renal function predict outcomes of urate-lowering therapy using low doses of febuxostat and benzbromarone: a prospective, randomized controlled study in a Chinese primary gout cohort

Background

Low doses of febuxostat or benzbromarone are widely used in Asian countries, but lacking studies to compare the efficacy and safety of the two urate-lowering drugs.

Methods

To compare the efficacy and safety of low-dose febuxostat with low-dose benzbromarone in patients with primary gout, a randomized controlled, open-label trial was performed among male patients with primary gout for urate-lowering therapy (ULT) in a dedicated gout clinic in China. Randomization was carried out by a third-party institution according to random number table. Patients were randomly assigned 1:1 to febuxostat group (Feb group) (20 mg daily) or benzbromarone group (Ben group) (25 mg daily) and treated for 12 weeks. General information and biochemical data were collected at baseline and at every visit monthly. Clinical characteristics before and after the ULT were analyzed in the two groups by SPSS and EmpowerStats software.

Results

Two hundred forty patients were enrolled and randomized in the two groups, with 214 patients completing 12 weeks’ ULT (105 in the Feb group and 109 in the Ben group). After 12 weeks, substantial percentages of patients in both Feb and Ben group achieved the target serum uric acid (sUA) (< 360 μmol/L) and serum urate levels were reduced significantly for both groups (Feb 39.5% and 156.83 μmol/L vs. Ben 35.7% and 163.99 μmol/L). Multivariate analysis suggests baseline sUA level and renal function were associated with the outcome of the rate of achieving target sUA (RAT). Sub-group analysis suggests low doses of febuxostat and benzbromarone rendered better RAT for patients with sUA < 540 μmol/L and creatinine clearance rate (Ccr) ≤ 110 mL min⁻¹ 1.73 m⁻² at baseline. The drugs were well tolerated, and the incidence of gout flares in Feb group was similar with that in Ben group (22.85% vs. 33.94%).

Conclusion

Overall, febuxostat 20 mg daily and benzbromarone 25 mg daily reduced sUA, and gout patients with sUA level < 540 μmol/L or Ccr ≤ 110 mL min⁻¹ 1.73 m⁻² at baseline had better chance to achieve target uric acid levels. The current study suggests sUA level and renal function are key factors to consider when recommending low doses of febuxostat and benzbromarone to gout patients.

Trial registration

Registered with ChiCTR, No. ChiCTR1800019352 (retrospectively registered).

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.

Side Effects and Interactions of the Xanthine Oxidase Inhibitor Febuxostat

The paper addresses the safety of febuxostat and summarizes reports on side effects and interactions of febuxostat published by the cut-off date (last day of literature search) of 20 March 2018. Publications on side effects and the interactions of febuxostat were considered. Information concerning the occurrence of side effects and interactions in association with the treatment with febuxostat was collected and summarized in the review. The incidence of severe side effects was much less frequent than mild side effects (1.2–3.8% to 20.1–38.7%). The rate and range of febuxostat side effects are low at doses of up to 120 mg and only increase with a daily dose of over 120 mg. The publications reveal no age-dependent increase in side effects for febuxostat. In patients with impaired renal function, no increase in adverse events is described with a dose of up to 120 mg of febuxostat per day. Patients with impaired liver function had no elevated risk for severe side effects. A known allopurinol intolerance increases the risk of skin reactions during treatment with febuxostat by a factor of 3.6. No correlation between treatment with febuxostat and agranulocytosis has been confirmed. Possible interactions with very few medications (principally azathioprine) are known for febuxostat. Febuxostat is well tolerated and a modern and safe alternative to allopurinol therapy.

Clinical Pharmacokinetics and Pharmacodynamics of Febuxostat

Febuxostat is a xanthine oxidoreductase inhibitor that has been developed to treat chronic gout. In healthy subjects, the pharmacokinetic parameters of febuxostat after multiple oral dose administration include an oral availability of about 85 %, an apparent oral clearance (CL/F) of 10.5 ± 3.4 L/h and an apparent volume of distribution at steady state (V _ss/F) of 48 ± 23 L. The time course of plasma concentrations follows a two-compartment model. The initial half-life (t _½) is approximately 2 h and the terminal t _½ determined at daily doses of 40 mg or more is 9.4 ± 4.9 h. Febuxostat is administered once daily. The maximum (peak) plasma concentrations are approximately 100-fold greater than the trough concentrations. Consequently, there is no significant accumulation of the drug during multiple dose administration. There are few data on the pharmacokinetics of febuxostat in patients with gout. While the pharmacokinetic parameters are not affected by mild to moderate hepatic impairment, there is no consensus on whether renal impairment has any effect on the pharmacokinetics of febuxostat. Febuxostat is extensively metabolised by oxidation (approximately 35 %) and acyl glucuronidation (up to 40 %); febuxostat acyl glucuronides are cleared by the kidney. In healthy subjects treated with multiple doses of febuxostat 10-240 mg, the concentrations of serum urate are reduced by a maximum of about 80 %. The percentage reduction in the concentrations of serum urate is slightly less in gouty patients than in healthy subjects.

Identification of chronic kidney disease patient characteristics influencing the renoprotective effects of febuxostat therapy: a retrospective follow-up study

Background

The ability of antihyperuricemic therapy to exert renoprotective effects in patients with chronic kidney disease (CKD) is controversial. In the present study, we studied patient characteristics that may mask favorable impact of antihyperuricemic therapy on the progression of CKD.

Methods

This was a single-center, retrospective, follow-up study. One-hundred and seventy-eight CKD patients with hyperuricemia who received febuxostat therapy were included in this study. Mean serum uric acid (mUA) level after treatment and changes in estimated glomerular filtration rate (ΔeGFR) over 6 months were measured and their correlation was examined. Patients were divided into two groups based on mUA, and their ΔeGFR were compared. These analyses were evaluated in various subgroups.

Results

Febuxostat therapy markedly decreased UA level in any CKD stage patients without resulting in serious adverse events. eGFRs of CKD patients in the mUA < 6.0 mg/dl group were maintained, whereas those in the mUA ≥ 6.0 mg/dl group decreased. A significant inverse correlation was observed between mUA and ΔeGFR (r = −0.16, p = 0.019). The renoprotective effects of febuxostat were significant in the following subgroups: male patients, age < 70 years, systolic blood pressure < 130 mmHg, normal cholesterol levels, and absence of diabetes. Coexisting vascular risk factors appear to exert additive masking effects against febuxostat renoprotection.

Conclusions

The results of this study suggest that various vascular risk factors markedly attenuate the renoprotective effects of febuxostat.

Electronic supplementary material

The online version of this article (doi:10.1186/s12882-017-0572-z) contains supplementary material, which is available to authorized users.

Risk of Febuxostat-Associated Myopathy in Patients with CKD

BACKGROUND AND OBJECTIVES

Febuxostat, a nonpurine xanthine oxidase inhibitor, is widely used to treat hyperuricemia. Although febuxostat-associated rhabdomyolysis was reported in some patients with CKD, the association between CKD and febuxostat-associated myopathy remains uncertain.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Our retrospective cohort study included 1332 patients using febuxostat in Taipei Medical University-Wanfang Hospital from February of 2014 to January of 2016. The primary predictor was time-averaged eGFR as calculated by the equation proposed by the 2009 Chronic Kidney Disease Epidemiology Collaboration. The outcome was febuxostat-associated myopathy defined as elevated creatine kinase levels during febuxostat use that were not attributed to other muscular injuries.

RESULTS

The median duration of febuxostat use was 224 days (25th, 75th percentiles: 86, 441.5 days). Of 1332 study participants, 1222 (91.7%) had CKD; the median eGFR was 20.8 ml/min per 1.73 m2 (25th, 75th percentiles: 9.0, 35.4 ml/min per 1.73 m2). Forty-one of the participants had febuxostat-associated myopathy (3.2%). All patients with myopathy had CKD, and the incident rate was 0.013 (95% confidence interval, 0.01 to 0.02) events per 100 patient-days in patients with CKD. Of 41 patients with myopathy, 37 had myositis, and four had rhabdomyolysis. Myopathy resolved in 17 patients who withdrew from treatment and eight patients who continued febuxostat treatment. Among the evaluated predictors, multivariate analysis showed that only the lowest eGFR tertile was significantly associated with myopathy in febuxostat users. The odds ratio of the lowest eGFR tertile to the highest tertile was 4.21 (95% confidence interval, 1.7 to 10.43). This finding remained consistent among subgroups stratified by age, sex, diabetes status, coronary artery disease, and statin or fibrate use.

CONCLUSIONS

Patients with severely reduced eGFR had higher risk of myopathy with treatment of febuxostat. Regular monitoring of creatine kinase level is suggested for early detection of febuxostat-associated myopathy, particularly in patients with CKD.

Comparative efficacy and safety of urate-lowering therapy for the treatment of hyperuricemia: a systematic review and network meta-analysis

The prevalence of hyperuricemia and gout has been increasing, but the comparative effectiveness and safety of different treatments remain uncertain. We aimed to compare the effectiveness and safety of different treatments for hyperuricemia using network meta-analysis methodology. We systematically reviewed fifteen randomized controlled trials (involving 7,246 patients through January 2016) that compared the effects of different urate-lowering drugs (allopurinol, benzbromarone, febuxostat, pegloticase and probenecid) on hyperuricemia. Drug efficacy and safety, as outcomes, were measured by whether the target level of serum urate acid was achieved and whether any adverse events occurred, respectively. We derived pooled effect sizes expressed as odds ratios (ORs) and 95% confidence intervals (CIs). The efficacy and safety of the drugs were ranked by cumulative ranking probabilities. Our findings show that febuxostat, benzbromarone, probenecid, pegloticase, and allopurinol were all highly effective at reducing the risk of hyperuricemia compared to placebo. Febuxostat had the best efficacy and safety compared to the other drugs. Furthermore, febuxostat 120 mg QD was more effective at achieving urate-lowering targets (OR: 0.17, 95% CI: 0.12-0.24) and safer (OR: 0.72, 95% CI: 0.56-0.91) than allopurinol.

Safety and efficacy of oral febuxostat for treatment of HLA-B*5801-negative gout: a randomized, open-label, multicentre, allopurinol-controlled study

Objectives: This phase IIIB study compared the efficacy and safety of febuxostat and allopurinol in gout patients with or without tophi who were HLA-B*5801 negative.

Method: Eligible patients were randomized to a febuxostat group (80 mg QD) or an allopurinol group (300 mg QD). Following an initial 2-week washout period, over the next 12 weeks we made five measurements of serum urate levels along with assessments of adverse events (AEs).

Results: Forty-three out of 152 screened subjects (28.3%) were ineligible either because of the presence of the HLA-B*5801 allele or for various other reasons. The febuxostat group (n = 54) and the allopurinol group (n = 55) had no significant differences in demographic or baseline characteristics. From week 2 to week 12, the febuxostat group had a significantly lower serum urate level than the allopurinol group (p ≤ 0.001 for all comparisons) and significantly more patients with serum urate levels less than 6.0 mg/dL. The serum urate levels of the febuxostat group declined by more than 40% from week 2 to week 12 and this decrease was greater than that in the allopurinol group (~30%). The two groups were similar in terms of AEs.

Conclusions: Febuxostat was more effective than allopurinol in reducing the serum urate levels of Han Chinese patients with gout or tophaceous gout who were HLA-B*5801 negative, without causing any serious skin reactions. Febuxostat should be considered for treatment of Han Chinese patients with gout who are HLA-B*5801 negative.

Comparison of the Renoprotective Effect of Febuxostat for the Treatment of Hyperuricemia between Patients with and without Type 2 Diabetes Mellitus: A Retrospective Observational Study

Objective The effects of febuxostat therapy on hyperuricemia in patients with and without type 2 diabetes were compared in this retrospective observational study after pair-matching using the propensity scores. Methods In total, 160 patients with hyperuricemia were studied as the treated set, and the 155 subjects in whom the administration of febuxostat was not discontinued during the observation period were investigated in the full analysis. The study subjects were divided into two groups based on the style of initiation of febuxostat: initial and switching therapy from allopurinol administration. Results The reduction in the serum uric acid (sUA) levels at six months after the initiation of febuxostat administration did not significantly differ between the patients with and without diabetes in both the initial (206±114 and 226±113 μmol/L in patients with and without diabetes, respectively) and switching (154±91 and 129±90 μmol/L in patients with and without diabetes, respectively) therapy groups. The eGFR values were significantly increased compared to the baseline levels only in the patients without diabetes. The changes in the eGFR values were significantly associated with the presence of diabetes and sUA at baseline in a multivariate analysis. The frequency of adverse events was not significantly different between the patients with and without diabetes. Conclusion Although febuxostat exerted a similar sUA-lowering effect against hyperuricemia in patients with type 2 diabetes compared to those without, the renoprotective effect was attenuated in those with diabetes compared to nondiabetic subjects.

Dual-energy computed tomography for monitoring the effect of urate-lowering therapy in gouty arthritis

OBJECTIVE

To investigate the relationships between changes in serum urate levels and dual-energy computed tomography (DE-CT) results during urate-lowering therapy (ULT) and to investigate the effects of treatment duration and drugs on changes in DE-CT results.

METHODS

Forty-four patients diagnosed with gout were enrolled in this investigation. DE-CT was conducted on the foot at baseline and the end of follow-up (6-24 months). Crystals were classified as: (i) L, number of large crystals with diameter ≥ 3 mm; (ii) S, number of small crystals with diameter < 3 mm; (iii) T, total number of crystals; and (iv) Vmax, volume of the maximal crystal.

RESULTS

Number of urate crystals (L, S as well as T) and Vmax decreased significantly through ULT. Significant decrease of urate crystal numbers and/or Vmax was observed in different follow-up groups, and the decrease in serum urate levels was positively related to the decrease of T (r = 0.43, P = 0.04) and Vmax (r = 0.63, P = 0.04). Moreover, analysis of covariance results demonstrated significant effects of treatment duration and serum urate levels on results of DE-CT.

CONCLUSION

Both urate crystal numbers and Vmax decreased significantly during ULT. Additionally, ULT duration and serum urate levels had significant effects on the decrease of Vmax and number of large crystals measured by DE-CT.

A phase 3, multicenter, randomized, allopurinol-controlled study assessing the safety and efficacy of oral febuxostat in Chinese gout patients with hyperuricemia

AIM

To compare the efficiency and safety of febuxostat with those of allopurinol in Chinese patients with gout and hyperuricemia.

METHODS

The trial which was conducted at 13 centers in China during 2011-2013 included a 2-week run-in and a 24-week treatment period. A total of 504 eligible participants with gout and with serum urate ≥ 480 μmol/L were randomly assigned 1 : 1 : 1 to febuxostat 40 mg/day, febuxostat 80 mg/day and allopurinol 300 mg/day groups. The primary efficacy endpoint was the percentage of subjects whose last three serum urate levels were < 360 μmol/L.

RESULTS

The primary efficacy endpoint was reached by 33.5% of subjects taking febuxostat 80 mg/day, 22.5% of those taking febuxostat 40 mg/day and 17.0% of those taking allopurinol 300 mg/day (P < 0.001 for the comparison between febuxostat 80 mg/day and allopurinol 300 mg/day groups; P = 0.216 for the comparison between febuxostat 40 mg/day and allopurinol 300 mg/day groups). The incidence of gout flare was relatively high in each group during the first 8 weeks and gradually decreased thereafter. There was no statistically significant difference between the three groups (P > 0.05). The incidence of adverse events was similar in the three treatment groups. The most frequent treatment-related adverse events were liver function test abnormalities.

CONCLUSIONS

Febuxostat 80 mg/day had superior urate-lowering efficacy to that of febuxostat 40 mg/day or allopurinol 300 mg/day, which was comparable in Chinese gout patients with hyperuricemia. Febuxostat, at a daily dose of 40 or 80 mg, was safe and well tolerated.

Associations Between Hyperuricemia and Chronic Kidney Disease: A Review

CONTEXT

In human beings, uric acid is the poorly soluble circulating end product of the purine nucleotide metabolism. A reduction in the glomerular filtration rate (GFR) contributes to hyperuricemia, which is frequently observed in patients with chronic kidney disease (CKD).

EVIDENCE ACQUISITION

Hyperuricemia is defined as a serum uric acid level > 7.0 mg/dL in males and > 6.0 mg/dL in females, while CKD is defined as kidney damage or a GFR < 60 mL/min/1.73 m(2) for 3 months or more, irrespective of the cause. Hyperuricemia is common in CKD and may occur because of decreased excretion, increased production, or a combination of both mechanisms.

RESULTS

The causes for hyperuricemia in overproducers may be either exogenous or endogenous. CKD has become a global public health problem because of its high prevalence and the accompanying increase in the risk of end-stage renal disease, cardiovascular disease, and premature death. The most common risk factors for CKD are obesity and the metabolic syndrome, which is strongly associated with hyperuricemia probably as a consequence of insulin resistance and the effects of insulin to reduce the urinary urate excretion. For recurring bouts of hyperuricemia or gout, patients should have a blood test and joint fluid test to determine whether the medication taken is effective. Interventional studies are a useful clinical research tool in clarifying the role of hyperuricemia in CKD.

CONCLUSIONS

Although many evidence-based studies have suggested that uric acid itself may harm patients with CKD by increasing inflammation and CKD progression, the issue is still a matter of controversy. Special attention should be paid to specific contraindications to certain drugs and the possibility of infectious arthritis.

Hypouricemic effect and safety of febuxostat used for prevention of tumor lysis syndrome

Purpose

We evaluated the efficacy and safety of febuxostat, a non-purine xanthine oxidase inhibitor, used for prevention of hyperuricemia associated with tumor lysis syndrome (TLS).

Methods

Records of adult patients with newly diagnosed or relapsed hematologic malignancies who received febuxostat within 7 days before initiation of chemotherapy were retrieved retrospectively at a single institute. The changes in serum uric acid levels from before and 7 days after initiation of febuxostat were evaluated and compared with the historical control group of patients who received allopurinol. We also evaluated non-hematological adverse events during the study period.

Results

A total of 78 patients’ records were analyzed, 38 in the febuxostat group and 39 in the allopurinol group. There were no significant differences in the incidence of treatment failure, defined as development of clinical TLS or receiving rasburicase, between the febuxostat and allopurinol group (5.2% vs 5.1%, P>0.99). The mean serum uric acid levels were significantly decreased, compared to the baseline (5.6 ± 2.1 mg/dL), at 7 days after initiation of febuxostat (3.1 ± 1.5 mg/dL, last observation carried forward, P<0.001). There were no statistically significant differences in the percent change in the serum uric acid levels between the 40 mg/day febuxostat and the 300 mg/day allopurinol groups (P = 0.57). Grade 3–4 liver dysfunctions were observed in both the febuxostat and allopurinol groups, without significant differences in incidence between the two groups (2.6% vs 5.1%, P>0.99). Neither gout flare nor skin rash occurred in any patients.

Conclusions

Febuxostat is feasible for prevention of hyperuricemia associated with TLS.

A systematic review and meta-analysis on the safety and efficacy of febuxostat versus allopurinol in chronic gout

OBJECTIVE

To evaluate the safety and efficacy of febuxostat compared to allopurinol for the treatment of chronic gout.

METHODS

We did a systematic review and meta-analysis of randomized and non-randomized controlled trials that compared oral febuxostat to oral allopurinol for treatment of chronic gout. Two reviewers independently selected studies, assessed study quality, and extracted data. Risk ratios (RR) were calculated with random effects and were reported with corresponding 95% confidence intervals (CI).

RESULTS

From 1076 potentially relevant citations, 7 studies and 25 associated publications met inclusion criteria; 5 studies were ultimately included in the analysis. Febuxostat did not reduce the risk of gout flares compared with allopurinol (RR = 1.16, 95% CI = 1.03-1.30, I(2) = 44%). Overall, the risk of any adverse event was lower in febuxostat recipients compared to allopurinol (RR = 0.94, 95% CI = 0.90-0.99, I(2) = 13%). Patients receiving febuxostat were more likely to achieve a serum uric acid of <6 mg/dl than allopurinol recipients (RR = 1.56, 95% CI = 1.22-2.00, I(2) = 92%). Subgroup analysis did not indicate any significant difference between high- and low-dose febuxostat on the risk of gout flares.

CONCLUSION

Although febuxostat was associated with higher likelihood of achieving a target serum uric acid level of <6 mg/dl, there was significant heterogeneity in the pooled results. There was no evidence that febuxostat is superior to allopurinol for clinically relevant outcomes. Given its higher cost, febuxostat should not be routinely used for chronic gout.

Chronic gout in the elderly

Gout is the most common cause of inflammatory arthritis in men over 40 years old; it is a debilitating disease and, if untreated, can result in a chronic progressive disease, including tophaceous gout. In the elderly it represents a special issue, with notable clinical and therapeutic differences from the classical form with a systemic involvement. The burden of the disease increases particularly in the very old people, in whom arthritis, impaired gait and eyesight problems may enhance the related disability. Chronic gout moreover could aggravate heart and kidney disease and increase overall mortality and organ-related damage. Early diagnosis and appropriate treatment are important goals for the clinician that should to rely on the cooperation of specialists working together through the methodology of comprehensive geriatric assessment. The aim of the present review was to analyze chronic gout in old people in terms of epidemiology, pathophysiology, risk factors, clinical approach, and current treatment.

Uric acid and chronic kidney disease: which is chasing which?

Serum uric acid is commonly elevated in subjects with chronic kidney disease (CKD), but was historically viewed as an issue of limited interest. Recently, uric acid has been resurrected as a potential contributory risk factor in the development and progression of CKD. Most studies documented that an elevated serum uric acid level independently predicts the development of CKD. Raising the uric acid level in rats can induce glomerular hypertension and renal disease as noted by the development of arteriolosclerosis, glomerular injury and tubulointerstitial fibrosis. Pilot studies suggest that lowering plasma uric acid concentrations may slow the progression of renal disease in subjects with CKD. While further clinical trials are necessary, uric acid is emerging as a potentially modifiable risk factor for CKD. Gout was considered a cause of CKD in the mid-nineteenth century, and, prior to the availability of therapies to lower the uric acid level, the development of end-stage renal disease was common in gouty patients. In their large series of gouty subjects Talbott and Terplan found that nearly 100% had variable degrees of CKD at autopsy (arteriolosclerosis, glomerulosclerosis and interstitial fibrosis). Additional studies showed that during life impaired renal function occurred in half of these subjects. As many of these subjects had urate crystals in their tubules and interstitium, especially in the outer renal medulla, the disease became known as gouty nephropathy. The identity of this condition fell in question as the presence of these crystals may occur in subjects without renal disease; furthermore, the focal location of the crystals could not explain the diffuse renal scarring present. In addition, many subjects with gout also had coexistent conditions such as hypertension and vascular disease, leading some experts to suggest that the renal injury in gout was secondary to these latter conditions rather than to uric acid per se. Indeed, gout was removed from the textbooks as a cause of CKD, and the common association of hyperuricemia with CKD was solely attributed to the retention of serum uric acid that is known to occur as the glomerular filtration rate falls. Renewed interest in uric acid as a cause of CKD occurred when it was realized that invalid assumptions had been made in the arguments to dismiss uric acid as a risk factor for CKD. The greatest assumption was that the mechanism by which uric acid would cause kidney disease would be via the precipitation as crystals in the kidney, similar to the way it causes gout. However, when laboratory animals with CKD were made hyperuricemic, the renal disease progressed rapidly despite an absence of crystals in the kidney. Since this seminal study, there has been a renewed interest in the potential role uric acid may have in both acute and CKD. We briefly review some of the major advances that have occurred in this field in the last 15 years.

Efficacy and tolerability of febuxostat in hyperuricemic patients with or without gout: a systematic review and meta-analysis

BACKGROUND

Febuxostat has been approved for the treatment of hyperuricemia in patients with/without gout.

OBJECTIVES

This meta-analysis and systematic review assessed the efficacy and tolerability of febuxostat in hyperuricemic patients with/without gout.

METHODS

Major electronic databases were searched for articles of all publication years (up to February 2012), as were the Web sites of the American College of Rheumatology, the European League Against Rheumatism, and the Chinese State Food and Drug Administration, and clinicaltrials.gov for unpublished studies. Only randomized, controlled trials (RCTs) were included.

RESULTS

Ten trials were included. A significantly greater proportion of patients achieved the target serum urate level (sUA ≤6.0 mg/dL) at the final visit in the febuxostat group compared with the placebo (OR = 235.73; P < 0.01) and allopurinol groups (OR = 3.14; P < 0.01). In subgroup analysis, the proportion of patients who achieved target sUA at the final visit was significantly greater in the febuxostat-treated group (40 mg/d) compared with the allopurinol-treated group (100-300 mg/d) (50.9% vs 45.6%; OR = 1.25; 95% CI, 1.05-1.49; P = 0.01). As the dosage was increased (40, 80, 120 mg/d), the proportion of patients who achieved target sUA in the febuxostat-treated group increased gradually (50.9%, 71.4%, 82%, respectively). There was no significant difference in the occurrence of adverse events (AEs) between the febuxostat- and allopurinol-treated groups.

CONCLUSION

Febuxostat was effective in reducing serum urate in hyperuricemic patients with/without gout, and febuxostat (40-120 mg/d) was more efficacious compared with allopurinol (100-300 mg/d). The doses of allopurinol to which febuxostat has been compared, although commonly prescribed, are low in the range of approved doses of allopurinol. The tolerability of febuxostat for the treatment of hyperuricemia with/without gout is similar to that of allopurinol.