Comparative efficacy and safety of dotinurad, febuxostat, and benzbromarone in hyperuricemic patients with or without gout: A network meta-analysis of randomized controlled trials.

OBJECTIVE: We aimed to assess the relative efficacy and safety of dotinurad (2 mg), benzbromarone (50 mg), and febuxostat (40 mg) in hyperuricemic patients with or without gout. MATERIALS AND METHODS: A Bayesian network meta-analysis was performed to combine direct and indirect evidence from randomized controlled trials (RCTs) to evaluate the efficacy and safety of dotinurad (2 mg), benzbromarone (50 mg), febuxostat (40 mg), and placebo in hyperuricemic patients with or without gout. RESULTS: Four RCTs, including 516 patients, fulfilled the inclusion criteria. The number of patients who achieved the target serum uric acid (sUA) level was significantly higher in the febuxostat 40-mg group than in the placebo group (OR 660.50, 95% credible interval (CrI) 75.47 - 19,584.80). The ranking probability based on the surface under the cumulative ranking curve (SUCRA) indicated that febuxostat 40 mg was more likely to achieve the best target sUA level (SUCRA = 0.849), followed by dotinurad 2 mg (SUCRA = 0.651), benzbromarone 50 mg (SUCRA = 0.501), and placebo (SUCRA < 0.001). The frequency of adverse drug reactions in the dotinurad 2-mg group, and in the benzbromarone 50-mg group tended to be lower than in the febuxostat 40-mg group. CONCLUSION: Febuxostat 40 mg and dotinurad 2 mg tended to be more effective than benzbromarone 50 mg, while dotinurad 2 mg and benzbromarone 50 mg tended to be safer than febuxostat 40 mg in hyperuricemic patients with or without gout.

Novel monocyclic amide-linked phenol derivatives without mitochondrial toxicity have potent uric acid-lowering activity.

Although benzbromarone (BBR) is a conventional, highly potent uricosuric drug, it is not a standard medicine because it causes rare but fatal fulminant hepatitis. We transformed the bis-aryl ketone structure of BBR to generate novel monocyclic amide-linked phenol derivatives that should possess uric acid excretion activity without adverse properties associated with BBR. The derivatives were synthesized and tested for uric acid uptake inhibition (UUI) in two assays using either urate transporter 1-expressing cells or primary human renal proximal tubule epithelial cells. We also evaluated their inhibitory activity against mitochondrial respiration as a critical mitochondrial toxicity parameter. Some derivatives with UUI activity had no mitochondrial toxicity, including compound 3f, which effectively lowered the plasma uric acid level in Cebus apella. Thus, 3f is a promising candidate for further development as a uricosuric agent.

Implementation Status of Liver Function Tests for Monitoring Benzbromarone-Induced Hepatotoxicity: An Epidemiological Survey Using the Japanese Claims Database.

A major adverse effect of benzbromarone is hepatotoxicity. Therefore, periodic liver function tests are required at least for the first 6 months of benzbromarone administration. However, it is not clear whether the relevant blood tests are implemented appropriately. Here, we performed a cross-sectional survey of the implementation status of liver function tests in patients who were newly prescribed benzbromarone, using the Japanese large claims database. Male patients who were newly prescribed benzbromarone from January 2010 to December 2016 were included. We targeted patients who continued benzbromarone during the observation period (up to 180 d from the start of administration). The primary endpoint was the proportion of patients in whom periodic liver function tests were implemented. A periodic liver function test was defined as one or more liver function tests performed during both 1-90 and 91-180 d of initial benzbromarone administration. We labeled the tests as a "periodic test" or "non-periodic test" based on whether periodic liver function tests were performed or not, respectively. Furthermore, factors influencing non-periodic test were analyzed. Periodic testing was implemented only in 28.7% of patients. Additionally, factors such as number of hospital beds ≤19 (compared to 100-199 beds) and duration of the first prescription of benzbromarone were associated with non-periodic testing. Our study revealed that periodic liver function tests are not performed sufficiently in Japan. Thus, clinicians prescribing benzbromarone should be educated about the test. Our blood-test-based approach should be applied to other drugs and countries in future research.

Comparative study of a novel selective urate reabsorption inhibitor "dotinurad" among patient groups with different stages of renal dysfunction.

BACKGROUND: Dotinurad is a selective urate reabsorption inhibitor (SURI), which selectively inhibits URAT1 to lower serum uric acid levels in patients with hyperuricemia. Herein, the effects of dotinurad were compared among patient groups with different stages of renal dysfunction. METHODS: Patient data from four clinical trials were pooled and divided into four groups according to the stage of renal dysfunction to compare the effects of dotinurad at different stages. The grouping (stages G1-G3b) was based on the estimated glomerular filtration rate (eGFR) of the patients. In addition, patient data from a long-term study (34 or 58 weeks) were evaluated in the same manner. RESULTS: In the pooled analysis, the percentage of patients achieving a serum uric acid level of ≤ 6.0 mg/dL was 64.7-100.0% at a dose of 2 or 4 mg. In the long-term analysis, the percentage of patients achieving a serum uric acid level of ≤ 6.0 mg/dL was 60.0-100.0% at a dose of 2 or 4 mg. Although the outcomes in stage G3b were worse due to higher baseline serum uric acid levels, satisfactory outcomes were observed in all stages. Even in stages G3a and G3b, when renal function declined, the eGFR remained constant throughout the dose period. CONCLUSION: The efficacy of dotinurad was confirmed in hyperuricemic patients with normal renal function (stage G1) and mild to moderate renal dysfunction (stage G2-G3b). Dotinurad was found to be effective in the treatment of hyperuricemia in patients with mild to moderate renal dysfunction.

Pharmacological Evaluation of Dotinurad, a Selective Urate Reabsorption Inhibitor.

The effect of dotinurad [(3,5-dichloro-4-hydroxyphenyl)(1,1-dioxo-1,2-dihydro-3H-1λ 6-1,3-benzothiazol-3-yl)methanone] was compared with that of commercially available uricosuric agents-namely, benzbromarone, lesinurad, and probenecid. Its effect on urate secretion transporters was evaluated using probe substrates for respective transporters. Dotinurad, benzbromarone, lesinurad, and probenecid inhibited urate transporter 1 (URAT1) with IC50 values of 0.0372, 0.190, 30.0, and 165 µM, respectively. Dotinurad weakly inhibited ATP-binding cassette subfamily G member 2 (ABCG2), organic anion transporter 1 (OAT1), and OAT3, with IC50 values of 4.16, 4.08, and 1.32 µM, respectively, indicating higher selectivity for URAT1. The hypouricemic effects of dotinurad and benzbromarone were evaluated in Cebus monkeys. Dotinurad, at doses of 1-30 mg/kg, concomitantly decreased plasma urate levels and increased fractional excretion of urate (FEUA) in a dose-dependent manner. On the contrary, benzbromarone, at a dose of 30 mg/kg, showed a modest effect on plasma urate levels. The inhibitory effect of dotinurad on urate secretion transporters was evaluated in Sprague-Dawley rats, with sulfasalazine and adefovir as probe substrates of ABCG2 and OAT1, respectively. Drugs, including febuxostat as a reference ABCG2 inhibitor, were administered orally before sulfasalazine or adefovir administration. Dotinurad had no effect on urate secretion transporters in vivo, whereas benzbromarone, lesinurad, probenecid, and febuxostat increased the plasma concentrations of probe substrates. These results suggested dotinurad is characterized as a selective urate reabsorption inhibitor (SURI), which is defined as a potent URAT1 inhibitor with minimal effect on urate secretion transporters, including ABCG2 and OAT1/3, because of its high efficacy in decreasing plasma urate levels compared with that of other uricosuric agents. SIGNIFICANCE STATEMENT: Our study on the inhibitory effects on urate transport showed that dotinurad had higher selectivity for urate transporter 1 (URAT1) versus ATP-binding cassette subfamily G member 2 (ABCG2) and organic anion transporter (OAT) 1/3 compared to other uricosuric agents. In Cebus monkeys, dotinurad decreased plasma urate levels and increased fractional excretion of urate in a dose-dependent manner. To determine the inhibitory effect of dotinurad on urate secretion transporters, we studied the movement of substrates of ABCG2 and OAT1 in rats. Dotinurad had no effect on these transporters, whereas the other uricosuric agents increased the plasma concentrations of the substrates. These results suggested dotinurad as a potent and selective urate reabsorption inhibitor is characterized by increased efficacy with decreasing plasma urate levels.

Venous thromboembolism in patients with gout and the impact of hospital admission, disease duration and urate-lowering therapy.

BACKGROUND: Systemic inflammatory diseases have been associated with increased risk of venous thromboembolism. We aimed to quantify the risk of venous thromboembolism in patients with gout, the most common inflammatory arthritis, and to assess how disease duration, hospital admission and urate-lowering therapy affect this risk. METHODS: We used data from the population-representative, England-based Clinical Practice Research Datalink linked to Hospital Episode Statistics, to identify incident gout cases between 1998 and 2017. We matched cases individually to 1 control without gout on age, gender, general practice and follow-up time. We calculated absolute and relative risks of venous thromboembolism, stratified by age, gender and hospital admission. Among those with gout, we assessed the risk of venous thromboembolism by exposure to urate-lowering therapy. RESULTS: We identified 62 234 patients with incident gout matched to 62 234 controls. Gout was associated with higher risk of venous thromboembolism compared with controls (absolute rate 37.3 [95% confidence interval (CI) 35.5-39.3] v. 27.0 [95% CI 25.5-28.9] per 10 000 person-years, adjusted hazard ratio [HR] 1.25, 95% CI 1.15-1.35). The excess risk in patients with gout, which was sustained up to a decade after diagnosis, was present during the time outside hospital stay (adjusted HR 1.30, 95% CI 1.18-1.42), but not during it (adjusted HR 1.01, 95% CI 0.83-1.24). The risk of venous thromboembolism was similar among patients prescribed versus not prescribed urate-lowering therapy (incidence rate ratio 1.04, 95% CI 0.89-1.23). INTERPRETATION: Gout was associated with higher risk of venous thromboembolism, particularly when the patient was not in hospital and regardless of exposure to urate-lowering therapy. Although the observed excess risk may not be sufficient to warrant preventive intervention, clinical vigilance may be required when caring for these patients.

Safety and efficacy of verinurad, a selective URAT1 inhibitor, for the treatment of patients with gout and/or asymptomatic hyperuricemia in the United States and Japan: Findings from two phase II trials.

Objective: Evaluate efficacy/safety of verinurad monotherapy in patients with gout (Japan/US) or asymptomatic hyperuricemia (Japan).Methods: Two randomized, placebo-controlled, phase II studies were conducted (NCT01927198/NCT02078219). Patients were randomized to once-daily doses of placebo or escalating doses of verinurad (study 1: 5-12.5 mg; study 2: 2.5-15 mg). Primary endpoint was percentage change from baseline in serum urate (sUA) at week 12 (study 1)/week 16 (study 2). Safety was also assessed.Results: Most patients in study 1 (n = 171) were white (74.9%); all patients were Japanese in study 2 (n = 204). Least squares means (±SE) estimate of percentage change in sUA levels from baseline in study 1 was 1.2 ± 2.9 for placebo, and -17.5 ± 2.8, -29.1 ± 2.8, -34.4 ± 2.9 for verinurad 5, 10, 12.5 mg, respectively. In study 2, results were -2.4 ± 2.5 and -31.7 ± 2.5, -51.7 ± 2.6,-55.8 ± 2.5, respectively. Difference from placebo was significant for each verinurad dose (p<.0001). The proportion of patients with treatment-emergent adverse events (TEAEs) was similar across all groups. Renal-related TEAEs were more common with verinurad than placebo.Conclusion: Verinurad monotherapy resulted in sustained reductions in sUA in Japanese/US patients but renal AEs occurred, so verinurad alone is not recommended for treatment of hyperuricemia or gout. The renal consequences of excessive uric acid excretion deserve study.

Clinical efficacy and safety of benzbromarone in elderly hypertensive patients with hyperuricemia.

To analyze the efficacy and safety of benzbromarone in elderly hypertensive patients with hyperuricemia. Sixty-six elderly hypertensive patients with hyperuricemia admitted to Beijing Civil Aviation General Hospital from February 2017 to February 2018 were enrolled in the study. According to computer randomization method, they were divided into two groups: The control group and the treatment group and there were 33 cases in each group. The routine treatment was used in the control group. The conventional treatment combined with benzbromarone treatment was applied to the treatment group. The clinical efficacy, blood pressure, blood uric acid level, inflammatory factor level and adverse event rate were analyzed. Clinical efficacy of the treatment group was higher than that of the control group (P<0.05); blood pressure, blood uric acid level, and inflammatory factor level in the treatment group was better than that of the control group (P<0.05); the incidence of adverse events in the treatment group was lower than that of the control group (P<0.05). Elderly hypertensive patients with hyperuricemia treated with benzbromarone have a significant clinical effect, which has a positive effect on improving clinical symptoms and reducing the probability of adverse events and has a high clinical promotion value.

Risk of fragility fracture among patients with gout and the effect of urate-lowering therapy.

BACKGROUND: Previous studies that quantified the risk of fracture among patients with gout and assessed the potential effect of urate-lowering therapy have provided conflicting results. Our study aims to provide better estimates of risk by minimizing the effect of selection bias and confounding on the observed association. METHODS: We used data from the Clinical Practice Research Datalink, which records primary care consultations of patients from across the United Kingdom. We identified patients with incident gout from 1990 to 2004 and followed them up until 2015. Each patient with gout was individually matched to 4 controls on age, sex and general practice. We calculated absolute rate of fracture and hazard ratios (HRs) using Cox regression models. Among patients with gout, we assessed the impact of urate-lowering therapy on fracture, and used landmark analysis and propensity score matching to account for immortal time bias and confounding by indication. RESULTS: We identified 31 781 patients with incident gout matched to 122 961 controls. The absolute rate of fracture was similar in both cases and controls (absolute rate = 53 and 55 per 10 000 person-years, respectively) corresponding to an HR of 0.97 (95% confidence interval 0.92-1.02). Our finding remained unchanged when we stratified our analysis by age and sex. We did not observe statistically significant differences in the risk of fracture among those prescribed urate-lowering therapy within 1 and 3 years after gout diagnosis. INTERPRETATION: Overall, gout was not associated with an increased risk of fracture. Urate-lowering drugs prescribed early during the course of disease had neither adverse nor beneficial effect on the long-term risk of fracture.

Lesinurad in combination with allopurinol: a randomised, double-blind, placebo-controlled study in patients with gout with inadequate response to standard of care (the multinational CLEAR 2 study).

OBJECTIVES: Determine the efficacy and safety of daily lesinurad (200 or 400 mg orally) added to allopurinol in patients with serum uric acid (sUA) above target in a 12-month, randomised, phase III trial. METHODS: Patients on allopurinol ≥300 mg (≥200 mg in moderate renal impairment) had sUA level of ≥6.5 mg/dL (≥387 µmol/L) at screening and two or more gout flares in the prior year. Primary end point was the proportion of patients achieving sUA level of <6.0 mg/dL (<357 µmol/L) (month 6). Key secondary end points were mean gout flare rate requiring treatment (months 7 through 12) and proportions of patients with complete resolution of one or more target tophi (month 12). Safety assessments included adverse events and laboratory data. RESULTS: Patients (n=610) were predominantly male, with mean (±SD) age 51.2±10.90 years, gout duration 11.5±9.26 years and baseline sUA of 6.9±1.2 mg/dL (410±71 µmol/L). Lesinurad at 200 and 400 mg doses, added to allopurinol, significantly increased proportions of patients achieving sUA target versus allopurinol-alone therapy by month 6 (55.4%, 66.5% and 23.3%, respectively, p<0.0001 both lesinurad+allopurinol groups). In key secondary end points, there were no statistically significant treatment-group differences favouring lesinurad. Lesinurad was generally well tolerated; the 200 mg dose had a safety profile comparable with allopurinol-alone therapy. Renal-related adverse events occurred in 5.9% of lesinurad 200 mg+allopurinol, 15.0% of lesinurad 400 mg+allopurinol and 4.9% of allopurinol-alone groups, with serum creatinine elevation of ≥1.5× baseline in 5.9%, 15.0% and 3.4%, respectively. Serious treatment-emergent adverse events occurred in 4.4% of lesinurad 200 mg+allopurinol, in 9.5% of lesinurad 400 mg+allopurinol and in 3.9% of allopurinol-alone groups, respectively. CONCLUSION: Lesinurad added to allopurinol demonstrated superior sUA lowering versus allopurinol-alone therapy and lesinurad 200 mg was generally well tolerated in patients with gout warranting additional therapy. TRIAL REGISTRATION NUMBER: NCT01493531.

Comparison of Clinical Advantage between Topiroxostat and Febuxostat in Hemodialysis Patients.

To determine the response of hemodialysis (HD) patients to topiroxostat after a switch from febuxostat, we evaluated the efficacy, tolerability, and serum concentration of topiroxostat in HD patients after the switch. In this 16-month prospective observational study, we assessed the serum uric acid (UA) levels, other laboratory data, and serum topiroxostat concentrations of 10 HD patients who had been receiving febuxostat at a dose of 10 mg/d for over 1 year. No statistical difference was observed between the tolerability index at baseline and 16 months after the switch to topiroxostat. Serum UA after the switch in all patients (attained serum UA levels of ≤6 mg/dL) was 5.6±1.7 mg/dL (60%) at baseline, 4.9±0.5 mg/dL (100%) at 6 months and 5.7±0.4 mg/dL (50%) at 16 months (p=0.25), respectively. In patients with baseline serum UA levels >6 mg/dL, serum UA was significantly reduced at 6 and 16 months compared with baseline. Minimum serum concentrations of serum topiroxostat were lower than the limit of quantification (<25 ng/mL). Our results indicate that a switch from febuxostat 10 mg/d to topiroxostat 40 mg/d might reduce serum UA levels, with no change in other clinical laboratory data over the long term. These effects were more frequent in patients with high serum UA levels. Furthermore, topiroxostat therapy was more cost effective than febuxostat therapy. Thus, topiroxostat therapy could be a better treatment option for HD patients who develop high serum UA levels after febuxostat 10 mg/d administration.

Stronger Uricosuric Effects of the Novel Selective URAT1 Inhibitor UR-1102 Lowered Plasma Urate in Tufted Capuchin Monkeys to a Greater Extent than Benzbromarone.

Urate-lowering therapy is indispensable for the treatment of gout, but available drugs do not control serum urate levels tightly enough. Although the uricosurics benzbromarone and probenecid inhibit a urate reabsorption transporter known as renal urate transporter 1 (URAT1) and thus lower serum urate levels, they also inhibit other transporters responsible for secretion of urate into urine, which suggests that inhibiting URAT1 selectively would lower serum urate more effectively. We identified a novel potent and selective URAT1 inhibitor, UR-1102, and compared its efficacy with benzbromarone in vitro and in vivo. In human embryonic kidney (HEK)293 cells overexpressing URAT1, organic anion transporter 1 (OAT1), and OAT3, benzbromarone inhibited all transporters similarly, whereas UR-1102 inhibited URAT1 comparably to benzbromarone but inhibited OAT1 and OAT3 quite modestly. UR-1102 at 3-30 mg/kg or benzbromarone at 3-100 mg/kg was administered orally once a day for 3 consecutive days to tufted capuchin monkeys, whose low uricase activity causes a high plasma urate level. When compared with the same dosage of benzbromarone, UR-1102 showed a better pharmacokinetic profile, increased the fractional excretion of urinary uric acid, and reduced plasma uric acid more effectively. Moreover, the maximum efficacy of UR-1102 was twice that of benzbromarone, suggesting that selective inhibition of URAT1 is effective. Additionally UR-1102 showed lower in vitro potential for mechanisms causing the hepatotoxicity induced by benzbromarone. These results indicate that UR-1102 achieves strong uricosuric effects by selectively inhibiting URAT1 over OAT1 and OAT3 in monkeys, and could be a novel therapeutic option for patients with gout or hyperuricemia.

The safety and efficacy of benzbromarone in gout in Aotearoa New Zealand.

BACKGROUND: Benzbromarone is a potent uricosuric but is not widely available due to concerns about hepatotoxicity. In Aotearoa New Zealand, benzbromarone has been available since April 2013, subject to funding restrictions, for patients with inadequate urate-lowering response or intolerance to allopurinol and probenecid. AIM: To assess the safety and efficacy of benzbromarone in a real-life setting. METHODS: All patients who received funding for benzbromarone from 1 April 2013 to 30 September 2014 were identified. Prescribers were sent a questionnaire for each individual. Information on demographics, efficacy of previous urate-lowering drugs and reasons for discontinuation were collected. Specific information about the dose, effect on serum urate, adverse effects and liver function tests after commencing benzbromarone was recorded. RESULTS: Completed questionnaires were returned for 123 of 164 (75%) patients. Mean (SD) serum urate prior to benzbromarone was 0.57 (0.12) mmol/L, and estimated glomerular filtration rate was 50.3 (22.8) mL/min/1.73 m(2) . The median dose of benzbromarone was 100 mg/day (25-200 mg/day). Six months after commencing benzbromarone, mean (SD) serum urate was 0.35 (0.12) mmol/L. Benzbromarone-related adverse events included rash (n = 4), diarrhoea (n = 9), nausea (n = 6) and urate stones (n = 3). Liver function test abnormalities were uncommon and tended to be mild. There were 14 patient deaths; none was considered related to benzbromarone. Allopurinol had been prescribed prior to benzbromarone in 117 of 123 patients; median maximum allopurinol dose was 200 mg/day (range 25-600 mg/day), and 19% patients received allopurinol >300 mg/day. CONCLUSION: Benzbromarone provides useful urate-lowering efficacy and does not appear unsafe in patients with gout. Urate-lowering therapy prescribing requires further optimisation.

Uricosuric medications for chronic gout.

BACKGROUND: Uricosuric agents have long been used in the treatment of gout but there is little evidence regarding their benefit and safety in this condition. OBJECTIVES: To assess the benefits and harms of uricosuric medications in the treatment of chronic gout. SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL, Issue 4, 2013), Ovid MEDLINE and Ovid EMBASE for studies to the 13 May 2013. We also searched the World Health Organization Clinical Trials Registry, ClinicalTrials.gov and the 2011 to 2012 American College of Rheumatology and European League against Rheumatism abstracts. WE considered black box warnings and searched drug safety databases to identify and describe rare adverse events. SELECTION CRITERIA: We considered all randomised controlled trials (RCTs) or quasi-randomised controlled trials (controlled clinical trials (CCTs)) that compared uricosuric medications (benzbromarone, probenecid or sulphinpyrazone) alone or in combination with another therapy (placebo or other active uric acid-lowering medication, or non-pharmacological treatment) in adults with chronic gout for inclusion. DATA COLLECTION AND ANALYSIS: Two review authors independently selected the studies for inclusion, extracted data and performed a risk of bias assessment. Main outcomes were frequency of acute gout attacks, serum urate normalisation, study participant withdrawal due to adverse events, total adverse events, pain reduction, function and tophus regression. MAIN RESULTS: The search identified four RCTs and one CCT that evaluated the benefit and safety of uricosurics for gout. One study (65 participants) compared benzbromarone with allopurinol for a duration of four months; one compared benzbromarone with allopurinol (36 participants) for a duration of nine to 24 months; one study (62 participants) compared benzbromarone with probenecid for two months and one study (74 participants) compared benzbromarone with probenecid. One study (37 participants) compared allopurinol with probenecid. No study was completely free from bias.Low-quality evidence from one study (55 participants) comparing benzbromarone with allopurinol indicated uncertain effects in terms of frequency of acute gout attacks (4% with benzbromarone versus 0% with allopurinol; risk ratio (RR) 3.58, 95% confidence interval (CI) 0.15 to 84.13), while moderate-quality evidence from two studies (101 participants; treated for four to nine months) indicated similar proportions of participants achieving serum urate normalisation (73.9% with benzbromarone versus 60% with allopurinol; pooled RR 1.27, 95% CI 0.90 to 1.79). Low-quality evidence indicated uncertain differences in withdrawals due to adverse events (7.1% with benzbromarone versus 6.1% with allopurinol; pooled RR 1.25, 95% CI 0.28 to 5.62), and total adverse events (20% with benzbromarone versus 6.7% with allopurinol; RR 3.00, 95% CI 0.64 to 14.16). The study did not measure pain reduction, function and tophus regression.When comparing benzbromarone with probenecid, there was moderate-quality evidence based on one study (62 participants) that participants taking benzbromarone were more likely to achieve serum urate normalisation after two months (81.5% with benzbromarone versus 57.1% with probenecid; RR 1.43, 95% CI 1.02 to 2.00). This indicated that when compared with probenecid, five participants needed to be treated with benzbromarone in order to have one additional person achieve serum urate normalisation (number needed to treat for an additional beneficial outcome (NNTB) 5). However, the second study reported no difference in the absolute decrease in serum urate between these groups after 12 weeks. Low-quality evidence from two studies (129 participants) indicated uncertain differences between treatments in the frequency of acute gout attacks (6.3% with benzbromarone versus 10.6% with probenecid; pooled RR 0.73, 95% CI 0.09 to 5.83); fewer withdrawals due to adverse events with benzbromarone (2% with benzbromarone versus 17% with probenecid; pooled RR 0.15, 95% CI 0.03 to 0.79, NNTB 7) and fewer total adverse events (21% with benzbromarone versus 47% with probenecid; pooled RR 0.43, 95% CI 0.25 to 0.74; NNTB 4). The studies did not measure pain reduction, function and tophus regression.Low-quality evidence based on one small CCT (37 participants) indicated uncertainty around the difference in the incidence of acute gout attacks between probenecid and allopurinol after 18 to 20 months' treatment (53% with probenecid versus 55% with allopurinol; RR 0.96, 95% CI 0.53 to 1.75). The study did not measure or report the proportion achieving serum urate normalisation, pain reduction, function, tophus regression, withdrawal due to adverse events and total adverse events. AUTHORS' CONCLUSIONS: There was moderate-quality evidence that there is probably no important difference between benzbromarone and allopurinol at achieving serum urate normalisation, but that benzbromarone is probably more successful than probenecid at achieving serum urate normalisation in people with gout. There is some uncertainty around the effect estimates, based on low-quality evidence from only one or two trials, on the number of acute gout attacks, the number of withdrawals due to adverse events or the total number of participants experiencing adverse events when comparing benzbromarone with allopurinol. However, when compared with probenecid, benzbromarone resulted in fewer withdrawals due to adverse events and fewer participants experiencing adverse events. Low-quality evidence from one small study indicated uncertain effects in the incidence of acute gout attacks when comparing probenecid with allopurinol therapy. We downgraded the evidence because of a possible risk of performance and other biases and imprecision.

Pegloticase. An excessively dangerous and inadequately evaluated hypouricaemic drug.

When severe gout with tophi persists despite treatment with allopurinol, a xanthine oxidase inhibitor, the hypouricaemic drug of choice is probenecid, a uricosuric agent, in the absence of a better alternative. Pegloticase is a pegylated recombinant uricase. This enzyme catabolises uric acid into allantoin, a water-soluble substance that is excreted by the kidneys. Pegloticase has been granted EU marketing authorisation in patients who continue to have severe gout attacks despite treatment with a xanthine oxidase inhibitor such as allopurinol. Pegloticase has not been compared with probenecid nor has it been evaluated in patients who have no other treatment options. Two double-blind, randomised, placebo-controlled trials have been conducted. They lasted only 6 months and involved 212 patients in whom allopurino/therapy had failed, usually because of serious adverse effects. Pegloticase lowered uric acid levels but increased the frequency of gout flares early during treatment. At best, it had only a minor symptomatic effect on pain and disability. Its long-term effects are unknown. About 10% of patients had a serious adverse effect attributed to pegloticase, including reactions during the infusion, anaphylactic reactions, and skin infections. Thrombocytopenia and severe cardiac adverse effects are other probable adverse effects. About 90% of patients treated with pegloticase developed anti-pegloticase antibodies. Given the limited short-term symptomatic efficacy and the absence of comparative long-term evaluation, patients should not be exposed to the potentially serious adverse effects of pegloticase. Probenecid is a better choice when allopurinol is ineffective or poorly tolerated. Currently, patients with no remaining therapeutic options should simply continue to receive symptomatic treatment of gout attacks.

Comparative efficacy and safety of uricosuric agents in the treatment of gout or hyperuricemia: a systematic review and network meta-analysis.

OBJECTIVES: The current world witnesses a greatly increased prevalence and incidence of hyperuricemia and gout with unfortunately the comparative efficacy and safety of present available uricosuric agents remaining uncertain. We herein aimed to investigate the most appropriate uricosuric agent for gout or hyperuricemia patients. METHOD: PubMed, Embase, Cochrane Library databases, and ClinicalTrials.gov from inception to 2 July 2022 were searched to retrieve eligible studies assessing efficacy and safety of uricosuric drugs in hyperuricemia or gout patients. Network meta-analysis was carried out using the Stata 16.0 software. RESULTS: Twelve randomized controlled trials comprising 1851 patients were eventually included. Network meta-analysis showed that dotinurad 4 mg once daily, verinurad, dotinurad 2 mg once daily, dotinurad 1 mg once daily, and benzbromarone were the top 5 effective treatments to achieve target serum uric acid. Furthermore, dotinurad 4 mg once daily was more effective at achieving urate-lowering targets (RR of dotinurad 4 mg once daily vs. probenecid: 1.68, 95% CI [1.13; 2.50]) and safer (RR of probenecid vs. dotinurad 4 mg once daily: 1.77, 95% CI [0.69; 4.56]) than probenecid. CONCLUSIONS: This network meta-analysis demonstrated an important absolute benefit of dotinurad 4 mg once daily to achieve target serum uric acid and low risk of adverse events for drug treatment of gout or hyperuricemia patients. Additionally, verinurad might be used as an alternative uricosuric therapeutic option to dotinurad. These findings provided further comprehensive insight into the treatment value of current uricosuric agents for gout or hyperuricemia. Key Points 1. This is the first systematic review and network meta-analysis examining the efficacy and safety of currently available uricosuric agents in gout or hyperuricemia patients. 2. Recommended doses of dotinurad 4mg once daily used for the treatment of gout or hyperuricemia patients can significantly decrease serum uric acid levels. 3. The present findings will provide further comprehensive insight into the treatment value of certain uricosuric agents for gout or hyperuricemia.

Dapagliflozin Added to Verinurad Plus Febuxostat Further Reduces Serum Uric Acid in Hyperuricemia: The QUARTZ Study.

CONTEXT: Combining a sodium-glucose cotransporter 2 inhibitor with a xanthine oxidase inhibitor (XOI) and a urate transporter 1 (URAT1) inhibitor may enhance serum uric acid (sUA) lowering. However, concerns exist regarding high urinary UA (uUA) excretion rates and subsequent crystallization in renal tubules. OBJECTIVE: To assess whether dapagliflozin added to verinurad, a selective URAT1 inhibitor, and febuxostat, an XOI, increases uUA excretion. DESIGN: Randomized, placebo-controlled, 2-way crossover study (NCT03316131). PATIENTS: Adults with asymptomatic hyperuricemia. INTERVENTIONS: Subjects (N = 36) were randomized to oral once-daily 9 mg verinurad plus 80 mg febuxostat plus 10 mg dapagliflozin for 7 days and 7 days of oral once-daily 9 mg verinurad plus 80 mg febuxostat plus placebo with an intervening 7- to 21-day washout period. MAIN OUTCOME MEASURE: Difference in peak uUA excretion between groups from baseline to day 7. Secondary outcomes included changes in sUA levels and 24-h uUA excretion. RESULTS: Both regimens lowered mean peak uUA excretion (least squares mean changes from baseline: -12.9 mg/h [95% confidence interval (CI): -21.0 to -4.7], dapagliflozin; -13.2 mg/h [95% CI -21.3 to -5.0], placebo). sUA concentrations were lower with dapagliflozin (mean treatment difference -62.3 µmol/L [95% CI -82.8 to -41.8]). Dapagliflozin did not impact verinurad pharmacokinetics, its main metabolites, or febuxostat or fasting plasma glucose levels vs verinurad plus febuxostat. There were no clinically relevant changes in safety parameters. CONCLUSIONS: Dapagliflozin further reduced sUA without influencing uUA excretion, suggesting that its combination with verinurad and febuxostat at the doses tested does not adversely affect kidney function. CLINICAL TRIAL REGISTRATION NUMBER: NCT03316131.

A randomised controlled trial on the efficacy and tolerability with dose escalation of allopurinol 300-600 mg/day versus benzbromarone 100-200 mg/day in patients with gout.

OBJECTIVES: To compare the efficacy and tolerability of allopurinol 300-600 mg/day versus benzbromarone 100-200 mg/day used to attain a target serum urate concentration (sUr) < or =0.30 mmol/l (5 mg/dl). METHODS: A randomised, controlled, open-label, multicentre trial in gout patients with renal function defined as a calculated creatinine clearance > or =50 ml/min. Patients were treated with 300 mg allopurinol or 100 mg benzbromarone once a day (stage 1). If sUr < or =0.30 mmol/l was not attained after 2 months, the dose was doubled to allopurinol 300 mg twice a day or benzbromarone 200 mg once a day (stage 2). The primary end point was treatment success in either of the two stages, defined as clinical tolerability and attainment of biochemical target sUr. RESULTS: Sixty-five patients were enrolled in stage 1; 36 received allopurinol and 29 received benzbromarone. Fifty-five patients (85%) were analysed at stage 1: the success rates were 8/31 (26%) and 13/25 (52%), respectively, and the difference was -0.26 (95% CI from -0.486 to -0.005), p = 0.049. At stage 2, the success rates were 21/27 (78%) and 18/23 (78%), respectively, and the difference was -0.005 (95% CI from -0.223 to 0.220), p = 1.00. Two patients stopped receiving allopurinol and three stopped receiving benzbromarone because of adverse drug reactions. CONCLUSIONS: Increasing the allopurinol dose from 300 to 600 mg/day and the benzbromarone dose from 100 to 200 mg/day according to the target sUr produced significantly higher success rates (both 78% successful in attaining sUr < or =0.30 mmol/l). No significant differences in treatment success between benzbromarone and allopurinol were found after dose escalation. TRIAL REGISTRATION NUMBER: ISRCTN49563848).

Safety and tolerability of available urate-lowering drugs: a critical review.

INTRODUCTION: Urate-lowering therapy (ULT) is the cornerstone of gout management, which is a widespread chronic illness characterized by hyperuricemia, arthropathy, tophus development, and urolithiasis. Since asymptomatic increased serum urate levels are associated with a higher risk of cardiovascular, renal and metabolic disorders, a larger use of ULTs in the general population is expected in the near future. AREAS COVERED: This review will focus on the safety and tolerability profile of the available urate-lowering drugs: xanthine oxidase inhibitors (XOIs), uricosuric agents and injectable uricases. EXPERT OPINION: Older drugs for ULT like allopurinol are well studied and extensively described from typical adverse effects (mild skin rash) to unusual fatal reactions, while febuxostat seems to be overall well tolerated. More evidence is required to define the safety profile of topiroxostat, arhalofenate, tranilast, and sulfinpyrazone. Furthermore, there are some unanswered questions about the pharmacological interactions of probenecid and the hepatotoxicity of benzbromarone. Despite a limited use in clinical practice, combination therapy with lesinurad or verinurad and XOI is not frequently accompanied by side effects. Rasburicase and pegloticase are usually well tolerated with some specific exceptions. Before prescribing UL drugs, physicians should take into account their safety profile tailoring the treatment on the patient characteristics.

Benzbromarone in the treatment of gout.

BACKGROUND: Benzbromarone is a uricosuric drug that has been used in the treatment of gout over the last 30 years. Due to its potent inhibition of the dominant apical (luminal) urate exchanger in the human proximal tubule URAT1, it reduces the urate reabsorption, diminishing serum urate levels and therefore preventing gout flares. Through several clinical trials, Benzbromarone has been proved effective and safe, inclusive in patients with chronic kidney disease and as combination therapy with allopurinol. Due to hepatotoxicity reports, it was withdrawn from the European market by the manufacturer, however many authors have questioned the product's withdrawal due to a lack of clinical evidence in order to support its hepatotoxicity. Benzbromarone is still available in several European countries, New Zealand, Brazil and several other countries. Despite the product's marketing over more than 20 years after the first hepatotoxicity reports, we have found only five reports in our literature search, and no prospective or retrospective study correlating hepatotoxicity with benzbromarone use. SHORT CONCLUSION: Benzbromarone is a safe and effective molecule for the treatment of gout. However, due to in vitro and in vivo data related to hepatotoxicity, it is prudent to prescribe it with some caution, especially for patients with an already known liver condition.