A Possible Therapeutic Application of the Selective Inhibitor of Urate Transporter 1, Dotinurad, for Metabolic Syndrome, Chronic Kidney Disease, and Cardiovascular Disease

The reabsorption of uric acid (UA) is mainly mediated by urate transporter 1 (URAT1) and glucose transporter 9 (GLUT9) in the kidneys. Dotinurad inhibits URAT1 but does not inhibit other UA transporters, such as GLUT9, ATP-binding cassette transporter G2 (ABCG2), and organic anion transporter 1/3 (OAT1/3). We found that dotinurad ameliorated the metabolic parameters and renal function in hyperuricemic patients. We consider the significance of the highly selective inhibition of URAT1 by dotinurad for metabolic syndrome, chronic kidney disease (CKD), and cardiovascular disease (CVD). The selective inhibition of URAT1 by dotinurad increases urinary UA in the proximal tubules, and this un-reabsorbed UA may compete with urinary glucose for GLUT9, reducing glucose reabsorption. The inhibition by dotinurad of UA entry via URAT1 into the liver and adipose tissues increased energy expenditure and decreased lipid synthesis and inflammation in rats. Such effects may improve metabolic parameters. CKD patients accumulate uremic toxins, including indoxyl sulfate (IS), in the body. ABCG2 regulates the renal and intestinal excretion of IS, which strongly affects CKD. OAT1/3 inhibitors suppress IS uptake into the kidneys, thereby increasing plasma IS, which produces oxidative stress and induces vascular endothelial dysfunction in CKD patients. The highly selective inhibition of URAT1 by dotinurad may be beneficial for metabolic syndrome, CKD, and CVD.

Safety and Efficacy of Dotinurad on Uric Acid in Patients With Chronic Kidney Disease With Estimated Glomerular Filtration Rate Below 25 mL/Min/1.73 m²

Introduction Dotinurad is being developed as a selective uric acid reabsorption inhibitor. However, its effect on lowering serum uric acid (UA) levels in chronic kidney disease (CKD) patients with severe renal dysfunction is unknown. Therefore, the purpose of this study was to determine the effect of dotinurad on renal function in CKD patients with an estimated glomerular filtration rate (eGFR) below 25 mL/min/1.73 m2. Methods Seven patients with CKD who received dotinurad 0.5 mg to 4 mg per day were studied retrospectively. Changes in UA, eGFR, and urine protein-to-creatinine ratio (UPCR) were analyzed. The observation period was 10.9±2.1 months. Results Serum UA levels were decreased and maintained with dotinurad administration. Nevertheless, there were no improvements noted in renal function. Additionally, no serious adverse effects were identified in any of the patients throughout the observation period. Conclusion Although the sample size in this study was small, our findings demonstrate the efficacy of dotinurad in individuals with advanced CKD who have an eGFR lower than 25 mL/min/1.73 m2.

Changes in Urinary Uric Acid Concentration after Dotinurad Administration to Patients with Hyperuricemia: A Post Hoc Analysis of Two Clinical Trials in Japan

Dotinurad has been approved in Japan as a selective urate reabsorption inhibitor for the treatment of gout and hyperuricemia. The relationship between uric acid crystallization and the use of uricosuric drugs is widely acknowledged; however, the relationship between changes in urinary uric acid concentration and urine pH or volume has not been sufficiently analyzed. Therefore, we investigated the changes in urinary uric acid concentration following dotinurad administration as well as the relationship between urine pH or volume and urinary uric acid concentration. This post hoc analysis used data from 2 clinical trials that included 12 and 26 patients with hyperuricemia who received dotinurad treatment (for 7 days on an inpatient basis and 14 weeks on an outpatient basis, respectively). The urinary uric acid concentration transiently increased in the early stages of dotinurad use and when its dose was increased, but decreased over time. No uric acid concentrations exceeded the soluble limit at any urine pH. An inverse correlation was observed between urine volume and urinary uric acid concentration. This study highlights the significance of adequately managing urinary uric acid concentrations by increasing urine volume and alkalinizing urine to prevent uric acid crystallization during dotinurad administration.

Overview of the pharmacokinetics and pharmacodynamics of URAT1 inhibitors for the treatment of hyperuricemia and gout

INTRODUCTION

Hyperuricemia is a common metabolic disease, which is a risk factor for gouty arthritis and ureteral stones and may also lead to cardiovascular and chronic kidney disease (CDK). Therefore, hyperuricemia should be treated early. Xanthine oxidase inhibitors (XOIs) and uricosuric agents (UAs), which target uric acid, are two types of medications that are used to treat gout and hyperuricemia. XOIs stop the body from producing excessive uric acid, while UAs eliminate it rapidly via the kidneys. Urate transporter 1 (URAT1) belongs to the organic anion transporter family (OAT) and is specifically localized to the apical membrane of the epithelial cells of proximal tubules. Unlike other organic anion transporter family members, URAT1 identifies and transports organic anions that are primarily responsible for urate transport.

AREAS COVERED

This article reviews the pharmacokinetics and pharmacodynamics of the existing URAT1 inhibitors to serve as a reference for subsequent drug studies.

EXPERT OPINION

The URAT1 inhibitors that are currently used as clinical drugs mainly include dotinurad, benzbromarone, and probenecid. Results indicate that RDEA3170 may be the most promising inhibitor, in addition to SHR4640, URC-102, and MBX-102, which are in the early stages of development.

The Efficacy and Safety of Dotinurad on Uric Acid and Renal Function in Patients with Hyperuricemia and Advanced Chronic Kidney Disease: A Single Center, Retrospective Analysis

Objective

We investigated the efficacy and safety of dotinurad, a selective urate reabsorption inhibitor, in hyperuricemic patients with advanced chronic kidney disease (CKD) (stage G3-5).

Patients and Methods

We retrospectively analyzed the cases of 34 patients (mean age, 68.6 ± 13.3 years; 17 men and 17 women) after 12 months of dotinurad treatment based on the changes in uric acid (UA) and the urine protein-to-creatinine ratio (UPCR) plus the annual change in estimated glomerular filtration rate (eGFR). Hyperuricemia (UA ≥6.0 mg/dL) and advanced CKD (mean eGFR: 32.0 ± 13.3 mL/min/1.73m2; stage G3, n=17; G4, n=13; G5, n=4) were present in all of the patients. The cases of 34 matched individuals with similar propensity scores (who were not taking dotinurad) were analyzed as a control group.

Results

UA values decreased significantly in the dotinurad group (7.1 ± 0.8 mg/dL to 5.9 ± 1.0 mg/dL, p<0.05) but those did not change in the control group. UPCR did not change in either group. Low-density lipoprotein cholesterol also decreased significantly in the dotinurad group (98.8 ± 43.4 mg/dL to 82.9 ± 33.1 mg/dL, p<0.05). With the 12-month dotinurad treatment, the annual change in the patients' eGFR was significantly improved from -6.0 ± 12.9 mL/min/1.73 m2/year to -0.9 ± 4.6 mL/min/1.73 m2/year (p<0.05), but there was no change in the control group.

Conclusion

Dotinurad can decrease UA levels and might attenuate renal function decline in individuals with hyperuricemia and advanced CKD.

Urate Transporter 1 Can Be a Therapeutic Target Molecule for Chronic Kidney Disease and Diabetic Kidney Disease: A Retrospective Longitudinal Study

Chronic kidney disease (CKD) is a major global health problem for which there are no curative drug treatments. Hyperuricemia is one of risk factors for CKD. The evidence on effects of uric acid (UA)-lowering treatments on the progression of CKD was very limited and previous meta-analyses used only trials which primarily used xanthin oxidase (XO) inhibitors because the reports on fulminant hepatitis due to benzbromarone kept us from using uricosuric agents for hyperuricemia patients. Dotinurad, a novel selective urate reabsorption inhibitor for the treatment of hyperuricemia, reduces serum UA levels by selectively inhibiting urate transporter 1 (URAT1). We retrospectively picked up patients who had taken dotinurad from June 2018 to August 2021 and compared metabolic parameters at baseline with the data at 3 and 6 months after the start of dotinurad. We found 84 patients, and approximately 74% of patients were complicated with CKD. After the start of dotinurad, improvements in serum lipids, systolic blood pressure, body weight, and albuminuria, in addition to reduction in serum UA, were observed. Dotinurad increased urinary UA excretion, and was effective to reduce serum UA in patients with both UA underexcretion type and renal UA overload type. Furthermore, urinary UA excretion was significantly and negatively correlated with serum creatine levels at baseline and at 6 months after the start of dotinurad, and the change in urinary UA excretion after 3 months was significantly and negatively correlated with change in serum creatine levels. The property of dotinurad, which selectively inhibits URAT1, but not other UA transporters, such as ATP-binding cassette, subfamily G, and 2 (ABCG2), which ABCG2 is a UA and uremic toxin exporter, may be beneficially associated with pathology of CKD. URAT1 can be a therapeutic target molecule for CKD and DKD.

An evaluation method for uric acid uptake inhibition using primary human proximal tubule epithelial cells treated with insulin

The effects of uricosuric agents have been evaluated in vitro with indices of uric acid uptake into human urate transporter 1 (URAT1)-overexpressed oocytes or cells. In the present study, we evaluated a method using primary human renal proximal tubule epithelial cells (RPTECs). Pretreatment of RPTECs with insulin significantly increased the uptake of uric acid into these cells. The uric acid uptake was inhibited in a concentration-dependent manner by the URAT1 inhibitors benzbromarone and dotinurad. Therefore, effects of uricosuric agents can be evaluated by the novel method, which is closer to the physiological system compared with previous methods.

Efficacy and safety of switching from febuxostat to dotinurad, a novel selective urate reabsorption inhibitor, in hyperuricemic patients with type 2 diabetic kidney disease: Protocol for a single-arm, open-label, prospective, exploratory study

BACKGROUND

Dotinurad is a novel uricosuric drug in Japan with selective and potent urate transporter 1 (URAT1) inhibitory activity. This study aims to evaluate the efficacy and safety of dotinurad in hyperuricemic patients with type 2 diabetic kidney disease by comparing serum levels of urate and plasma and urinary levels of indoxyl sulfate excreted via the urate excretion transporter ATP binding cassette subfamily G member 2 (ABCG2), as indices, with baseline levels after switching from febuxostat to dotinurad.

METHODS

This single-center, single-arm, open-label, prospective, exploratory study aims to evaluate the effect of switching from febuxostat to dotinurad on serum urate levels and its background factors. The study will include 50 hyperuricemic patients with type 2 diabetic kidney disease and urate levels exceeding 6 mg/dL despite administration of febuxostat 20 mg/day for at least 3 months. The primary outcome is the achievement rate of serum urate levels of ≤6 mg/dL after 24 weeks of treatment with dotinurad at 0.5 mg to a maximum of 4 mg once daily. Secondary outcomes include the changes in serum urate levels, plasma and urinary indoxyl sulfate levels, and renal injury-related markers from baseline to observation points at weeks 4, 12, and 24.

DISCUSSION

The study hypothesizes that switching to dotinurad may reduce the plasma levels of indoxyl sulfate and increase its urinary levels in patients with hyperuricemia. These suggest that dotinurad can potently lower the serum urate level by inhibiting URAT1 without adversely affecting ABCG2. Thus, findings of this study are expected to provide useful insights into the treatment of hyperuricemia associated with type 2 diabetic kidney disease and the discovery of new possibilities for dotinurad.

ETHICS AND DISSEMINATION

Prior to the study, its study protocol was scientifically and ethically reviewed and approved by the Japan Physicians Association Clinical Research Review Board (approval number: JPA007-2204-02). In addition, patients who provide written informed consent will participate in the study. The results of this study will be published through submission to a peer-reviewed scientific journal.

CLINICAL TRIAL REGISTRATION

https://jrct.niph.go.jp/en-latest-detail/jRCTs031220080, identifier jRCTs031220080.

Uric acid-lowering effect of dotinurad, a novel selective urate reabsorption inhibitor, in hypertensive patients with gout or asymptomatic hyperuricemia: a pooled analysis of individual participant data in phase II and III trials

Background: Hyperuricemia is a risk factor for the development of hypertension and is comorbid in many hypertensive patients. According to Japanese hypertension management guidelines published in 2019, a target serum uric acid level of ≤6.0 mg/dL is recommended in hypertensive patients with gout or asymptomatic hyperuricemia. Dotinurad is a novel uric acid-lowering drug classified as a selective urate reabsorption inhibitor. A pooled analysis was performed on the uric acid-lowering effect of dotinurad in 222 hypertensive patients with gout or asymptomatic hyperuricemia in four clinical trials (NCT02344862, NCT02416167, NCT03100318, NCT03372200). Moreover, we analyzed the long-term uric acid-lowering effect of dotinurad in 154 hypertensive patients with gout or asymptomatic hyperuricemia (NCT03006445).Results: In the pooled analysis, the percent change in the decrease of serum uric acid with the use of dotinurad was 42.17 ± 12.42% at a dose of 2 mg and 60.42 ± 8.03% at a dose of 4 mg; the percentage of patients who achieved a serum uric acid level of ≤6.0 mg/dL was 82.8% and 100.0%. The long-term uric acid-lowering effect of dotinurad showed almost the same results. In this study, the concomitant use of diuretics or angiotensin II receptor blockers affected the uric acid-lowering effect of dotinurad at only a dose of 2 mg in the pooled analysis.Conclusions: In the pooled analysis, dotinurad lowered serum uric acid levels. Dotinurad has an achievement rate of over 80% for serum uric acid level of ≤6.0 mg/dL in both analyses, and will be clinically useful for the management of hyperuricemic states in hypertensive patients.

Dotinurad: a novel selective urate reabsorption inhibitor for the treatment of hyperuricemia and gout

INTRODUCTION

Gout is an inflammatory disease triggered by deposition of urate crystals secondary to longstanding hyperuricemia, and its management implies both the treatment of flares and management of hyperuricemia. Dotinurad is a selective urate reabsorption inhibitor (SURI), potently inhibits urate transporter 1 in the apical surface of renal proximal tubular cells, and has been approved for the treatment of gout and hyperuricemia in Japan.

AREAS COVERED

This overview of dotinurad covers nonclinical and clinical pharmacology studies in special populations and its efficacy and safety in Japanese hyperuricemic patients with and without gout.

EXPERT OPINION

Dotinurad, as an SURI, is expected to inhibit urate reabsorption more effectively than conventional urate-lowering agents. It is noninferior to benzbromarone or febuxostat in reducing serum urate levels in hyperuricemic patients with or without gout. Its efficacy is not attenuated in patients with mild to moderate renal impairment or with hepatic impairment. At a maintenance dose of 2 or 4 mg once daily, most patients achieved the target serum urate level of ≤6 mg/dL in a long-term study. No findings that raised safety concerns, including liver injury, were identified. Dotinurad is expected to be a new therapeutic option in hyperuricemic patients with and without gout.

Efficacy and Safety of Dotinurad in Hyperuricemic Patients With or Without Gout: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Introduction A systematic review and meta-analysis of the available randomized controlled trials (RCTs) were conducted to investigate the efficacy and safety of dotinurad in hyperuricemic patients with or without gout. Dotinurad is a novel selective urate reabsorption inhibitor (SURI) that increases uric acid excretion by selectively inhibiting urate transporter 1 (URAT1). To the best of our knowledge, this is the first meta-analysis conducted to gauge the efficacy and safety of dotinurad.  Methods Electronic databases (PubMed, the Cochrane Library, and ClinicalTrials.gov) were searched from inception till March 2, 2021, according to the Preferred Reporting Items for Systematic Review and Meta-Analysis statement. Randomized controlled trials comparing the efficacy and safety of dotinurad with placebo- or active (febuxostat or benzbromarone) control were included. The eligible studies were analyzed with RevMan 5.3 Software (The Nordic Cochrane Centre, Cochrane Collaboration, Copenhagen). Results Four eligible studies, consisting of 684 hyperuricemic patients were included. The number of patients who achieved serum uric acid (sUA) levels ≤ 6.0 mg/dl favoured dotinurad 1 mg group as compared to placebo group (risk ratio {RR} = 39.27, 95% onfidence interval {CI}, 5.59 to 275.65; p = 0.0002), dotinurad 2 mg group compared with placebo group (RR = 45.36, 95% CI, 6.48 to 317.38; p= 0.0001), and dotinurad 4 mg group compared with placebo group (RR = 54.16, 95% CI, 7.76 to 377.77; p < 0.0001). Conversely, there was no significant difference in the number of patients who achieved the target sUA levels between dotinurad 2 mg and active control (RR = 1.00, 95% CI, 0.92 to 1.08; p = 0.91). Moreover, the percentage change in sUA levels from baseline to final visit favoured dotinurad 1 mg vs. placebo ((RR = 36.51, 95% CI, 33.00 to 40.02; p < 0.00001), dotinurad 2 mg vs. placebo (RR = 46.70, 95% CI, 42.53 to 50.87; p < 0.00001), and dotinurad 4 mg vs. placebo (RR = 63.84, 95% CI, 60.51 to 67.16; p < 0.00001), while no significant difference was seen in dotinurad 2 mg vs. active control (RR = -0.08, 95% CI, -4.27 to 4.11; p= 0.97). Compared with active or placebo control, dotinurad 2 mg showed no significant difference in the number of events of gouty arthritis (RR= 1.31, 95% CI, 0.47 to 3.71; p = 0.60), the number patients with adverse events (RR = 1.09, 95% CI, 0.91 to 1.30; p = 0.36), and the number of patients who experienced adverse drug reactions (RR = 1.00, 95% CI, 0.68 to 1.47; p = 0.99). Conclusion Dotinurad shows significant improvement in serum uric acid levels in hyperuricemic individuals with or without gout. Its urate-lowering effect is comparable to the commonly available anti-hyperuricemic agents. Moreover, it is effective at doses 1 mg, 2 mg, and 4 mg and well-tolerated at a dose of 2 mg.

Pharmacokinetic/pharmacodynamic modeling and simulation of dotinurad, a novel uricosuric agent, in healthy volunteers

This study aimed to investigate the pharmacokinetic and pharmacodynamic (PK/PD) profiles of dotinurad, a novel uricosuric agent, and to construct a PK/PD model to predict serum urate (SUA) levels after dotinurad administration in healthy men. PK/PD model was constructed using single-dose study data considering the physiological features of urate handling. Model validation was performed by comparing the predicted SUA levels with the SUA levels in a multiple-dose study. Dotinurad was absorbed rapidly, and its exposure increased proportionally in the tested dose ranges (0.5-20 mg) after a single-dose administration. The PK model after oral administration was described using a one-compartment model with first-order absorption. Effects on SUA and renal urate excretion of dotinurad increased with dose escalation but were apparently saturable at a dose >5 mg. The simple maximal effect (Emax) model was selected as the PD model of dotinurad on renal urate reabsorption, resulting in an estimated Emax of 0.51. The plasma concentration at the half-maximal effect of dotinurad was 196 ng/mL. Other PD parameters were calculated from the change in SUA level or urinary excretion of urate before and after dotinurad administration. The predicted SUA levels, using the PK/PD model, were well-fitted with the observed values. The constructed PK/PD model of dotinurad appropriately described the profiles of dotinurad plasma concentrations and SUA level in multiple administration study.