Renal Function in Gout: Long-Term Treatment Effects of Febuxostat

Efficacy and safety of febuxostat, a novel nonpurine selective inhibitor of xanthine oxidase for the treatment of hyperuricemia in kidney transplant recipients

BACKGROUND

Febuxostat, a novel nonpurine selective inhibitor of xanthine oxidase, is a potential alternative to allopurinol for patients with hyperuricemia. In this study, we evaluated the efficacy and safety of febuxostat for the management of hyperuricemia in renal transplant recipients.

PATIENTS AND METHODS

Between June 2012 and January 2013, a total of 22 renal transplant recipients (56 ± 10 years old) with hyperuricemia were enrolled in this study. All patients underwent de novo kidney transplantation, except for 1 patient, who received a second kidney transplant. Ten patients receiving allopurinol and 3 patients receiving benzbromarone were converted to febuxostat at doses of 10-20 mg/d. In the remaining 9 patients, who did not have a history of other urate-lowering medications, febuxostat was initiated at a dose of 10 mg/d.

RESULTS

Uric acid levels after initiation of febuxostat were significantly lower than before treatment (5.7 ± 0.7 mg/mL vs 8.0 ± 0.8 mg/mL; P < .001). At last follow-up visit, 16 of the 22 patients (73%) achieved uric acid levels of ≤ 6.0 mg/dL, despite the low dosage of febuxostat. All patients were maintained on febuxostat without serious adverse events, except for 1 patient, who discontinued febuxostat because of numbness in the arms.

CONCLUSIONS

Low-dose febuxostat is a promising alternative to allopurinol or benzbromarone for the treatment of hyperuricemia in kidney transplant recipients. The long-term urate-lowering efficacy and safety of febuxostat with regard to renal function in kidney transplant recipients with hyperuricemia requires further investigation.

Glycosuria-mediated urinary uric acid excretion in patients with uncomplicated type 1 diabetes mellitus

Plasma uric acid (PUA) is associated with metabolic, cardiovascular, and renal abnormalities in patients with type 2 diabetes but is less well understood in type 1 diabetes (T1D). Our aim was to compare PUA levels and fractional uric acid excretion (FEUA) in patients with T1D vs. healthy controls (HC) during euglycemia and hyperglycemia. PUA, FEUA, blood pressure (BP), glomerular filtration rate (GFR-inulin), and effective renal plasma flow (ERPF-paraaminohippurate) were evaluated in patients with T1D (n = 66) during clamped euglycemia (glucose 4-6 mmol/l) and hyperglycemia (9-11 mmol/l), and in HC (n = 41) during euglycemia. To separate the effects of hyperglycemia vs. increased glycosuria, parameters were evaluated during clamped euglycemia in a subset of T1D patients before and after sodium glucose cotransporter 2 (SGLT2) inhibition for 8 wk. PUA was lower in T1D vs. HC (228 ± 62 vs. 305 ± 75 μmol/l, P < 0.0001). In T1D, hyperglycemia further decreased PUA (228 ± 62 to 199 ± 65 μmol/l, P < 0.0001), which was accompanied by an increase in FEUA (7.3 ± 3.8 to 11.6 ± 6.7, P < 0.0001). In T1D, PUA levels correlated positively with SBP (P = 0.029) and negatively with ERPF (P = 0.031) and GFR (P = 0.028). After induction of glycosuria with SGLT2 inhibition while maintaining clamped euglycemia, PUA decreased (P < 0.0001) and FEUA increased (P < 0.0001). PUA is lower in T1D vs. HC and positively correlates with SBP and negatively with GFR and ERPF in T1D. Glycosuria rather than hyperglycemia increases uricosuria in T1D. Future studies examining the effect of uric acid-lowering therapies should account for the impact of ambient glycemia, which causes an important uricosuric effect.

Improving cardiovascular and renal outcomes in gout: what should we target?

Epidemiological and experimental studies have shown that hyperuricaemia and gout are intricately linked with hypertension, metabolic syndrome, chronic kidney disease and cardiovascular disease. A number of studies suggest that hyperuricaemia and gout are independent risk factors for the development of these conditions and that these conditions account, in part, for the increased mortality rate of patients with gout. In this Review, we first discuss the links between hyperuricaemia, gout and these comorbidities, and present the mechanisms by which uric acid production and gout might favour the development of cardiovascular and renal diseases. We then emphasize the potential benefit of urate-lowering therapies on cardiovascular and renal outcomes in patients with hyperuricaemia. The mechanisms that link elevated serum uric acid levels and gout with these comorbidities seem to be multifactorial, implicating low-grade systemic inflammation and xanthine oxidase (XO) activity, as well as the deleterious effects of hyperuricaemia itself. Patients with asymptomatic hyperuricaemia should be treated by nonpharmacological means to lower their SUA levels. In patients with gout, long-term pharmacological inhibition of XO is a treatment strategy that might also reduce cardiovascular and renal comorbidities, because of its dual effect of lowering SUA levels as well as reducing free-radical production during uric acid formation.

Febuxostat for hyperuricemia in patients with advanced chronic kidney disease

Febuxostat is a nonpurine xanthine oxidase (XO) inhibitor, which recently received marketing approval. However, information regarding the experience with this agent among advanced chronic kidney disease (CKD) patients is limited. In the current study, we investigated the effects of oral febuxostat in patients with advanced CKD with asymptomatic hyperuricemia. We demonstrated, for the first time, that not only the serum levels of uric acid (UA) but also those of 8-hydroxydeoxyguanosine, an oxidative stress marker, were significantly reduced after six months of febuxostat treatment, with no adverse events. These results encouraged us to pursue further investigations regarding the clinical impact of lowering the serum UA levels with febuxostat in advanced CKD patients in terms of concomitantly reducing oxidative stress via the blockade of XO. More detailed studies with a larger number of subjects and assessments of the effects of multiple factors affecting hyperuricemia, such as age, sex, and dietary habits, would shed light on the therapeutic challenges of treating asymptomatic hyperuricemia in patients with various stages of CKD.

Four-week effects of allopurinol and febuxostat treatments on blood pressure and serum creatinine level in gouty men

The aim of this study was to observe the effects of uric acid lowering therapy (UALT), febuxostat and allopurinol, on blood pressure (BP) and serum creatinine level. Post-hoc data were derived from a phase-III, randomised, double-blind, 4-week trial of male gouty patients that compared the safety and efficacy of febuxostat and allopurinol in adults with gout. The subjects were randomly assigned to one of five groups, 35-37 in each group (febuxostat: 40, 80, 120 mg/d; allopurinol: 300 mg/d; control group: placebo). Blood pressure and serum creatinine level were measured at baseline and at weeks 2 and 4. Diastolic BP and creatinine level had decreased significantly in the UALT groups compared to the control group at week 4. Diastolic BP had decreased significantly in the allopurinol group and serum creatinine level had decreased significantly in the febuxostat groups at week 4. After adjusting for confounding variables, serum uric acid changes were found to be significantly correlated with changes in serum creatinine level but were not associated with changes in systolic or diastolic BP. UALT in gouty subjects significantly decreased diastolic BP and serum creatinine level. Changes in uric acid were significantly correlated with those in serum creatinine level, suggesting the feasibility of renal function improvement through UALT in gouty men.

Uric Acid - key ingredient in the recipe for cardiorenal metabolic syndrome

Elevated serum uric acid levels are a frequent finding in persons with obesity, hypertension, cardiovascular and kidney disease as well as in those with the cardiorenal metabolic syndrome (CRS). The increased consumption of a fructose-rich Western diet has contributed to the increasing incidence of the CRS, obesity and diabetes especially in industrialized populations. There is also increasing evidence that supports a causal role of high dietary fructose driving elevations in uric acid in association with the CRS. Animal and epidemiological studies support the notion that elevated serum uric acid levels play an important role in promoting insulin resistance and hypertension and suggest potential pathophysiological mechanisms that contribute to the development of the CRS and associated cardiovascular disease and chronic kidney disease. To this point, elevated serum levels of uric acid appear to contribute to impaired nitric oxide production/endothelial dysfunction, increased vascular stiffness, inappropriate activation of the renin-angiotensin-aldosterone system, enhanced oxidative stress, and maladaptive immune and inflammatory responses. These abnormalities, in turn, promote vascular, cardiac and renal fibrosis as well as associated functional abnormalities. Small clinical trials have suggested that uric acid-lowering therapies may be beneficial in such patients; however, a consensus on the treatment of asymptomatic hyperuricemia is lacking. Larger randomized controlled trials need to be performed in order to critically evaluate the beneficial effect of lowering serum uric acid in patients with the CRS and those with diabetes and/or hypertension.

Effect of pegloticase on renal function in patients with chronic kidney disease: a post hoc subgroup analysis of 2 randomized, placebo-controlled, phase 3 clinical trials

BACKGROUND

Pegloticase is approved in the US for treatment of refractory chronic gout. Since chronic kidney disease (CKD) is common in these patients, we conducted a post-hoc analysis of 2 replicate phase 3 trials and the subsequent open-label extension study to determine the effects of pegloticase on renal function in patients with CKD stages 3 and 4, as well as the effects of renal dysfunction on pegloticase efficacy and safety.

FINDINGS

Patients with renal insufficiency were randomized to pegloticase 8 mg every 2 weeks (n = 42), pegloticase 8 mg every 4 weeks (n = 41), or placebo (n = 20) for 6 months as defined by the study protocols. Renal function was assessed by estimated glomerular filtration rate (eGFR). All patients completing the randomized trials could participate in an open-label extension study for a further 2.5 years. Uric acid response, the primary end point in the trials, was plasma uric acid <6.0 mg/dl for 80% of months 3 and 6.Mean eGFR in both pegloticase dosing cohorts remained constant over the randomized treatment phase and long-term open-label extension study. The number of patients achieving uric acid response was similar across CKD stages (32% stage 1, 23% stage 2, 35% stage 3, and 39% stage 4, respectively, P = 0.3). There was no difference in the pegloticase safety profile based on CKD stage.

CONCLUSIONS

Pegloticase treatment does not impact eGFR in CKD patients and response to pegloticase is independent of CKD stage.

TRIAL REGISTRATION

Clinical trial identifier: NCT00325195.

The effect of febuxostat to prevent a further reduction in renal function of patients with hyperuricemia who have never had gout and are complicated by chronic kidney disease stage 3: study protocol for a multicenter randomized controlled study

BACKGROUND

Hyperuricemia is a risk factor for the onset of chronic kidney disease (CKD) and is significantly associated with the progression of CKD. However, there is no sufficient evidence by interventional research supporting a cause-effect relationship. Hyperuricemic patients without gouty arthritis, whose serum urate (SUA) concentration is ≥8.0 mg/dL and who have a complication, are treated by pharmacotherapy in addition to lifestyle guidance. Nevertheless, there is no evidence that rationalizes pharmacotherapy for patients with hyperuricemia who have no complication and whose SUA concentration is below 9.0 mg/dL.

METHODS/DESIGN

The FEATHER (FEbuxostat versus placebo rAndomized controlled Trial regarding reduced renal function in patients with Hyperuricemia complicated by chRonic kidney disease stage 3) study is a prospective, multicenter, double-blind, randomized, placebo-controlled trial of febuxostat-a novel, nonpurine, selective, xanthine oxidase inhibitor. The present study will enroll, at 64 medical institutions in Japan, 400 Japanese patients aged 20 years or older who have hyperuricemia without gouty arthritis, who present CKD stage 3, and whose SUA concentration is 7.1-10.0 mg/dL. Patients are randomly assigned to either the febuxostat or the control group, in which febuxostat tablets and placebo are administered orally, respectively. The dosage of the study drugs should be one 10-mg tablet/day at weeks 1 to 4 after study initiation, increased to one 20-mg tablet/day at weeks 5 to 8, and elevated to one 40-mg tablet/day at week 9 and then maintained until week 108. The primary endpoint is estimated glomerular filtration rate (eGFR) slope. The secondary endpoints include the amount and percent rate of change in eGFR from baseline to week 108, the amount and percent rate of change in SUA concentration from baseline to week 108, the proportion of patients who achieved an SUA concentration≤6.0 mg/dL, and the incidence of renal function deterioration.

DISCUSSION

The present study aims to examine whether febuxostat prevents a further reduction in renal function as assessed with eGFR in subjects and will (1) provide evidence to indicate the inverse association between a reduction in SUA concentration and an improvement in renal function and (2) rationalize pharmacotherapy for subjects and clarify its clinical relevance.

TRIAL REGISTRATION

UMIN Identifier: UMIN000008343.

Febuxostat (Feburic tablet) in the management of hyperuricemia in a general practice cohort of Japanese patients with a high prevalence of cardiovascular problems

Hyperuricemia is increasing in prevalence and this is paralleled by an increased incidence of acute gout. In addition, there is growing evidence of an association between high serum levels of uric acid (sUA) and cardiovascular disease (CVD). In this preliminary report, we present 12-16 week results from a multicenter, general practice study in which we evaluated the usefulness of febuxostat in a cohort of untreated patients with hyperuricemia with a high prevalence of CVD. Febuxostat titrated from 10 mg/day up to 40 mg/day resulted in statistically significant and clinically relevant reductions in sUA after 12-16 weeks. A "responder" level of 6.0 mg/dL or lower was achieved in 95 of 100 (95%) patients. Significant reductions in sUA were achieved regardless of the presence/absence of coexisting diseases (e.g. CVD, renal insufficiency, diabetes and obesity) or the class of antihypertensive agent being used by the patient. No serious adverse reactions were noted with febuxostat. Although allopurinol has been used generally for hyperuricemia/gout, it is excreted fully via the kidneys, restricting its use in patients with reduced renal function, and its three-times-daily administration leads to poor adherence. Based on the results of this study, febuxostat may provide an easier option than allopurinol for clinicians specializing in CVDs.

Febuxostat for treating allopurinol-resistant hyperuricemia in patients with chronic kidney disease

BACKGROUND

Availability of the novel xanthine oxidase inhibitor febuxostat, which has multiple excretion pathways, enables investigation of the significance of serum uric acid control on renal function in patients with chronic kidney disease (CKD).

METHODS

This was an exploratory, retrospective, observational study conducted at a single Japanese center. Serum uric acid concentrations and serum creatinine levels in the 6 months before and after the start of febuxostat treatment were collected for CKD patients switched from allopurinol after failing to achieve serum uric acid concentrations ≤6.0 mg/dL.

RESULTS

Evaluable data were available for 60 patients, 67% of whom had advanced CKD (eGFR <30 mL/min/1.73 m2). Mean dose of febuxostat was 15.9 (± 8) mg/day. Mean serum uric acid concentration decreased from 8.4 (±1.4) mg/dL at baseline to 6.2 (±1.2) mg/dL at 6 months; 47.5% of patients achieved a level ≤6.0 mg/dL. The change from baseline in eGFR was positive at all time points during febuxostat treatment and the increase of 2.3 (±5.6) mL/min/1.73 m2 at 6 months was significant (p = 0.0027). Whereas the eGFR slope was negative during allopurinol treatment, it became positive after the switch to febuxostat. The change in eGFR slope before and after febuxostat treatment was significant for all patients (p < 0.01), for male patients (p < 0.05), and for patients with a baseline eGFR of <15 mL/min/1.73 m2 (p < 0.05).

CONCLUSIONS

In patients with CKD, febuxostat reduces serum uric acid concentrations effectively and may suppress the progressive decline in renal function.

Novel drugs and intervention strategies for the treatment of chronic kidney disease

Chronic kidney disease (CKD) is a worldwide health problem. The disease is most often progressive of nature with a high impact on patients and society. It is increasingly recognized that CKD can be detected in the early stages and should be managed as early as possible. Treatment of the cause, but in particular control of the main risk markers, such as high blood pressure, glucose and albuminuria, has been instrumental in delaying the progression to end-stage renal disease (ESRD). However, despite the state of the art therapy, the absolute risk of renal and cardiovascular morbidity and mortality in CKD patients remains devastatingly high. Novel drugs are therefore highly desirable to halt effectively the progressive renal (and cardiovascular) function loss. Recently, several novel strategies have been tested targeting traditional risk factors such as blood pressure (combination therapy of angiotensin converting enzyme inhibitors (ACEi) and angiotensin receptor blockers (ARB) and novel mineralocorticoid receptor antagonists) as well as dyslipidaemia (statins) with surprising results. In addition, drug targets specifically related to the kidney, such as vitamin D, uric acid, erythropoietin and phosphate, have been the subject of clinical trials, in some instances with unexpected results. Finally, novel targets including endothelin receptors and inflammatory pathways are increasingly explored as potential avenues to improve renal and cardiovascular protection, albeit that the drugs tested have not been unequivocally successful. In this article we review novel drugs or intervention strategies for the management of CKD, we try to provide explanations for the failure of some promising drugs and hypothesize on the potential success of new strategies.

Effects of uric acid-lowering therapy on renal outcomes: a systematic review and meta-analysis

BACKGROUND

Non-randomized studies suggest an association between serum uric acid levels and progression of chronic kidney disease (CKD). The aim of this systematic review is to summarize evidence from randomized controlled trials (RCTs) concerning the benefits and risks of uric acid-lowering therapy on renal outcomes.

METHODS

Medline, Excerpta Medical Database and Cochrane Central Register of Controlled Trials were searched with English language restriction for RCTs comparing the effect of uric acid-lowering therapy with placebo/no treatment on renal outcomes. Treatment effects were summarized using random-effects meta-analysis.

RESULTS

Eight trials (476 participants) evaluating allopurinol treatment were eligible for inclusion. There was substantial heterogeneity in baseline kidney function, cause of CKD and duration of follow-up across these studies. In five trials, there was no significant difference in change in glomerular filtration rate from baseline between the allopurinol and control arms [mean difference (MD) 3.1 mL/min/1.73 m2, 95% confidence intervals (CI) -0.9, 7.1; heterogeneity χ2=1.9, I2=0%, P=0.75]. In three trials, allopurinol treatment abrogated increases in serum creatinine from baseline (MD -0.4 mg/dL, 95% CI -0.8, -0.0 mg/dL; heterogeneity χ2=3, I2=34%, P=0.22). Allopurinol had no effect on proteinuria and blood pressure. Data for effects of allopurinol therapy on progression to end-stage kidney disease and death were scant. Allopurinol had uncertain effects on the risks of adverse events.

CONCLUSIONS

Uric acid-lowering therapy with allopurinol may retard the progression of CKD. However, adequately powered randomized trials are required to evaluate the benefits and risks of uric acid-lowering therapy in CKD.

Serum urate and incidence of kidney disease among veterans with gout

OBJECTIVE

To study the association between serum urate level (sUA) and the risk of incident kidney disease among US veterans with gouty arthritis.

METHODS

From 2002 through 2011 adult male patients with gout who were free of kidney disease were identified in the data from the Veterans Administration VISN 16 database and were followed until incidence of kidney disease, death, or the last available observation. Accumulated hazard curves for time to kidney disease were estimated for patients with average sUA levels > 7 mg/dl (high) versus ≤ 7 mg/dl (low) based on Kaplan-Meier analyses; and statistical comparison was conducted using a log-rank test. A Cox proportional hazard model with time-varying covariates was used to estimate the unadjusted and adjusted hazard ratios for kidney disease.

RESULTS

Eligible patients (n = 2116) were mostly white (53%), with average age 62.6 years, mean body mass index 31.2 kg/m(2), and high baseline prevalence of hypertension (93%), hyperlipidemia (67%), and diabetes (20%). Mean followup time was 6.5 years. The estimated rates of all incident kidney disease in the overall low versus high sUA groups were 2% versus 4% at Year 1, 3% versus 6% at Year 2, and 5% versus 9% at Year 3, respectively (p < 0.0001). After adjustment, high sUA continued to predict a significantly higher risk of kidney disease development (HR 1.43, 95% CI 1.20-1.70).

CONCLUSION

Male veterans with gout and sUA levels > 7 mg/dl had an increased incidence of kidney disease.

Serum uric acid and cardio-renal diseases

OBJECTIVES

In this article, the results of clinical and experimental studies that examine the association of hyperuricemia and gout with hypertension and kidney disease are presented and discussed.

METHODS

Key papers for inclusion were identified by a PubMed search, and articles were selected according to their relevance for the topic, according to the authors' judgment.

RESULTS AND CONCLUSIONS

Increasing evidence supports a causal role for Uric acid (UA) in hypertension. Further larger studies are needed to confirm the possible beneficial role of UA lowering drugs and/or xantine-oxidase (XO) inhibitors. Overall, clinical evidence suggests a relationship of UA level with incident chronic kidney disease (CKD). In addition, the results of clinical trials using urate lowering therapy provide some promising evidence that lowering UA levels may retard the progression of CKD. Reviewed data indicate the need for large, well designed studies in these patients to evaluate XO inhibitors or uricosuric drugs in cardio-renal diseases and further elucidate the role of UA in the development and progression of CKD.

Changes in serum uric acid have a reciprocal effect on eGFR change: a 10-year follow-up study of community-based screening in Okinawa, Japan

Hyperuricemia is common among patients with hypertension and metabolic syndrome and therefore may be a cause of or result from these comorbid conditions. Few studies, however, have examined the relationship between the presence-absence of hyperuricemia and changes in the estimated glomerular filtration rate (eGFR) using the large cohort of the general population. We examined subjects who participated in two screenings, in 1993 and 2003, in Okinawa, Japan, yielding data on serum creatinine and uric acid levels (N=16,630). eGFR (ml min(-1) per 1.73 m(2)) was calculated using the formula used by the Japanese Society of Nephrology. In both sexes, a uric acid (UA) level >7.0 mg dl(-1) was defined as hyperuricemia (H), and a UA level below that threshold was classified as normouricemia (N). Based on the absence or presence of hyperuricemia in both the 1993 screening and the 2003 screening, we categorized patients into four groups: group 1, N/N; group 2, H/N; group 3, N/H; and group 4, H/H. Multiple regression analysis was performed to estimate the independent effects of several variables on the decline in eGFR. In all groups, an increase in UA from 1993 to 2003 (ΔUA) was a strong independent risk factor for a decline in eGFR than that of the baseline levels of UA, the presence of hypertension, or diabetes. The estimated decline in eGFR per 1 mg dl(-1) increase in UA was 4.19, 1.91, 2.36 and 2.01 ml min(-1) per 1.73 m(2) in groups 1, 2, 3 and 4, respectively. The results suggest that UA has a role in chronic kidney disease (CKD) progression. We have no information on medications used, such as xanthine oxidase, uricosuric drugs and hypotensives; therefore, the impact of hyperuricemia might be underestimated in our analysis. The results suggest that maintaining a normal range of UA is important to maintain eGFR decline in a normal range.

Reduced glomerular function and prevalence of gout: NHANES 2009-10

Background

The renal tubule is a major route of clearance of uric acid, a product of purine metabolism. The links between reduced glomerular filtration rate (GFR), hyperuricemia, and gout in the general population are not well understood. The objective of the present study was to estimate prevalence of gout and hyperuricemia among people with impaired GFR in the US general population.

Study Design

Cross-sectional, survey-weighted analyses of data on adults (age>20 years) in the 2009–10 cycle of the US National Health and Nutrition Examination Surveys (n = 5,589). Associations between self-reported physician diagnosis of gout and degrees of renal impairment were the primary focus of the present analyses.

Results

In the 2009–2010 period, there was an estimated 7.5 million people with gout in the US. There were 1.25 million men and 0.78 million women with moderate or severe renal impairment and gout. The age standardized prevalence of gout was 2.9% among those with normal GFR compared to 24% among those with GFR<60 ml/min/1.73 m².In multivariable logistic regression analyses that adjusted for age, gender, body mass index, hypertension, diabetes, hypertension medications, including diuretics, blood lead levels, and hyperlipidemia, the odds ratios of gout and hyperuricemia were 5.9 (2.2, 15.7) and 9.58 (4.3, 22.0) respectively among those with severe renal impairment compared to those with no renal impairment. Approximately 2–3 fold increase in prevalence of gout was observed for each 30 ml/min/1.73 m² decrease in GFR, after accounting for the above factors.

Conclusions

Renal glomerular function is an important risk factor for gout. The prevalence of hyperuricemia and gout increases with decreasing glomerular function independent of other factors. This association is non-linear and an eGFR of 60 ml/min/1.73 m² appears to be a threshold for the dramatic increase in the prevalence of gout.

[Gout as a systemic disease. Manifestations, complications and comorbidities of hyperuricaemia]

Of all inflammatory rheumatic diseases gout has the highest prevalence. Patients with intermittent acute gout attacks are usually treated by primary care physicians. However, in cases of insufficient long-term control of serum uric acid levels, complications or atypical clinical manifestations may necessitate consultation with a rheumatologist in the further course of the disease. An oligoarticular or polyarticular presentation can give rise to the initial suspicion of rheumatoid or psoriatic arthritis. In these cases a careful clinical work-up supported by laboratory and imaging investigations is necessary and synovial fluid analysis is usually required. As in other rheumatic diseases extra-articular manifestations are of utmost importance for morbidity and mortality. Gout is a complex metabolic and inflammatory disease and besides articular symptoms the renal and cardiovascular effects of hyperuricemia are particularly relevant for the overall prognosis.

Treating hyperuricemia of gout: safety and efficacy of febuxostat and allopurinol in older versus younger subjects

Despite an increasing incidence of gout in older age patients with multiple metabolic and cardiovascular comorbidities, there are limited data addressing whether currently available urate-lowering therapy is comparably effective and safe in older (≥65 years of age) versus younger (<65 years of age) patients. In this secondary analysis of data from the CONFIRMS trial, we found that among 374 older subjects, urate-lowering therapy with approved doses of febuxostat or commonly prescribed doses of allopurinol was at least comparable to that in 1894 younger subjects and was well tolerated despite high rates of renal impairment and cardiovascular comorbidities in the older subjects.

The efficacy and safety of febuxostat for urate lowering in gout patients ≥65 years of age

Background

The incidence of gout rises with increasing age. Management of elderly (≥65 years) gout patients can be challenging due to high rates of comorbidities, such as renal impairment and cardiovascular disease, and concomitant medication use. However, there is little data specifically addressing the efficacy and safety of available urate-lowering therapies (ULT) in the elderly. The objective of this post hoc analysis was to examine the efficacy and safety of ULT with febuxostat or allopurinol in a subset of elderly subjects enrolled in the CONFIRMS trial.

Methods

Hyperuricemic (serum urate [sUA] levels ≥ 8.0 mg/dL) gout subjects were enrolled in the 6-month, double-blind, randomized, comparative CONFIRMS trial and randomized, 1:1:1, to receive febuxostat, 40 mg or 80 mg, or allopurinol (200 mg or 300 mg based on renal function) once daily. Flare prophylaxis was provided throughout the study duration.

Study endpoints were the percent of elderly subjects with sUA <6.0 mg/dL at the final visit, overall and by renal function status, percent change in sUA from baseline to final visit, flare rates, and rates of adverse events (AEs).

Results

Of 2,269 subjects enrolled, 374 were elderly. Febuxostat 80 mg was significantly more efficacious (82.0%) than febuxostat 40 mg (61.7%; p < 0.001) or allopurinol (47.3%; p < 0.001) for achieving the primary efficacy endpoint. Febuxostat 40 mg was also superior to allopurinol in this population (p = 0.029). In subjects with mild-to-moderate renal impairment, significantly greater ULT efficacy was observed with febuxostat 40 mg (61.6%; p = 0.028) and febuxostat 80 mg (82.5%; p < 0.001) compared to allopurinol 200/300 mg (46.9%). Compared to allopurinol 200/300 mg, the mean percent change in sUA from baseline was significantly greater for both febuxostat 80 mg (p < 0.001) and febuxostat 40 mg (p = 0.011) groups. Flare rates declined steadily in all treatment groups. Rates of AEs were low and comparable across treatments.

Conclusions

These data suggest that either dose of febuxostat is superior to commonly prescribed fixed doses of allopurinol (200/300 mg) in subjects ≥65 years of age with high rates of renal dysfunction. In addition, in this high-risk population, ULT with either drug was well tolerated.

Trial registration

clinicaltrials.gov NCT#00430248

African American patients with gout: efficacy and safety of febuxostat vs allopurinol

BACKGROUND

African Americans are twice as likely as Caucasians to develop gout, but they are less likely to be treated with urate-lowering therapy (ULT). Furthermore, African Americans typically present with more comorbidities associated with gout, such as hypertension, obesity, and renal impairment. We determined the efficacy and safety of ULT with febuxostat or allopurinol in African American subjects with gout and associated comorbidities and in comparison to Caucasian gout subjects.

METHODS

This is a secondary analysis of the 6-month Phase 3 CONFIRMS trial. Eligible gouty subjects with baseline serum urate (sUA) ≥ 8.0 mg/dL were randomized 1:1:1 to receive febuxostat 40 mg, febuxostat 80 mg, or allopurinol (300 mg or 200 mg depending on renal function) daily. All subjects received gout flare prophylaxis. Primary efficacy endpoint was the proportion of subjects in each treatment group with sUA < 6.0 mg/dL at the final visit. Additional endpoints included the proportion of subjects with mild or with moderate renal impairment who achieved a target sUA < 6.0 mg/dL at final visit. Adverse events (AEs) were recorded throughout the study.

RESULTS

Of the 2,269 subjects enrolled, 10.0% were African American and 82.1% were Caucasian. African American subjects were mostly male (89.5%), obese (BMI ≥ 30 kg/m2; 67.1%), with mean baseline sUA of 9.8 mg/dL and mean duration of gout of 10.4 years. The proportions of African American subjects with a baseline history of diabetes, renal impairment, or cardiovascular disease were significantly higher compared to Caucasians (p < 0.001). ULT with febuxostat 80 mg was superior to both febuxostat 40 mg (p < 0.001) and allopurinol (p = 0.004). Febuxostat 40 mg was comparable in efficacy to allopurinol. Significantly more African American subjects with mild or moderate renal impairment achieved sUA < 6.0 mg/dL in the febuxostat 80 group than in either the febuxostat 40 mg or allopurinol group (p < 0.05). Efficacy rates in all treatment groups regardless of renal function were comparable between African American and Caucasian subjects, as were AE rates.

CONCLUSIONS

In African American subjects with significant comorbidities, febuxostat 80 mg is significantly more efficacious than either febuxostat 40 mg or allopurinol 200/300 mg. Febuxostat was well tolerated in this African American population.Please see related article: http://www.biomedcentral.com/1741-7015/10/15.

Efficacy and safety of febuxostat in patients with hyperuricemia and gout

The past decade has witnessed an exponential increase of novel therapeutic modalities for a variety of rheumatic disorders, including gout. During the past few years two novel therapeutic agents have been approved by the US Food and Drug Administration for the treatment of hyperuricemia in patients with gout, one of them being febuxostat, a nonpurine selective inhibitor of xanthine oxidase. Review of its pharmacokinetics and pharmacodynamics, efficacy and safety profile, and use in gout patients with comorbid conditions reveals that age and gender have no clinically significant effect and dose adjustments based on age or gender are not required. In addition, febuxostat can be used in patients with mild-to-moderate renal or hepatic involvement. Its overall efficacy and safety profile is comparable and, in certain subsets such as gout patients with mild and moderate renal insufficiency, is superior to allopurinol.

Tophaceous gout and renal insufficiency: a new solution for an old therapeutic dilemma

The prevalence of gout is increasing with increased life expectancy. Approximately half of the patients with gout have some degree of renal impairment. If both conditions persistently coexist, and in severe tophaceous gout, in particular, treatment has been difficult. We here report on the case of an 87-year-old woman, who had been suffering from recurrent gouty arthritis over 4 years. Monthly polyarthritis attacks were accompanied by subcutaneous tophi. Serum uric acid levels were constantly above 600 μmol/L (10 mg/dL). Allopurinol was no option because of intolerance, while benzbromarone was ineffective because of renal impairment. Therefore, the novel xanthin oxidase inhibitor febuxostat was started, achieving rapid control of serum urate levels (<360 μmol/L). After initial worsening of inflammation in the first weeks, gouty attacks stopped and all tophi resolved within the following 10 months. Renal function remained stable.