Febuxostat in the management of hyperuricemia and chronic gout: a review

Management of hypertension addressing hyperuricaemia: introduction of nano-based approaches

Uric acid (UA) levels in blood serum have been associated with hypertension, indicating a potential causal relationship between high serum UA levels and the progression of hypertension. Therefore, the reduction of serum UA level is considered a potential strategy for lowering and mitigating blood pressure. If an individual is at risk of developing or already manifesting elevated blood pressure, this intervention could be an integral part of a comprehensive treatment plan. By addressing hyperuricaemia, practitioners may subsidize the optimization of blood pressure regulation, which illustrates the importance of addressing UA levels as a valuable strategy within the broader context of hypertension management. In this analysis, we outlined the operational principles of effective xanthine oxidase inhibitors for the treatment of hyperuricaemia and hypertension, along with an exploration of the contribution of nanotechnology to this field.

Regulation of redox enzymes by nutraceuticals: a review of the roles of antioxidant polyphenols and peptides

Redox enzymes are essential components of the cellular defence system against oxidative stress, which is a common factor in various diseases. Therefore, understanding the role of bioactive nutraceuticals in modulating the activity of these enzymes holds immense therapeutic potential. This paper provides a comprehensive review of the regulation of redox enzymes in cell and animal models by food-derived bioactive nutraceuticals, focusing on polyphenols and peptides. Specifically, this paper discusses the regulation of superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT), NAPDH oxidase, xanthine oxidase (XO), myeloperoxidase (MPO), and haem oxygenase (HO) in cell and animal models. Polyphenols, which are abundant in fruits, vegetables, and beverages, have diverse antioxidant properties, including direct scavenging of reactive oxygen species and regulation of transcription factors such as nuclear factor erythroid 2-related factor 2, which leads to the increased expression of the redoxenzymes SOD, HO, and GPx. Similarly, bioactive peptides from various food proteins can enhance antioxidative enzyme activity by regulating gene expression and directly activating the enzyme CAT. In other cases, an antioxidative response requires the downregulation or inhibition of the redox enzymes XO, MPO, and NAPDH oxidase. This paper highlights the potential of bioactive nutraceuticals in mitigating oxidative stress-related diseases and their mechanisms in modulating the redox enzyme expression or activity. Furthermore, the review highlights the need for further research to uncover new therapeutic strategies using nutraceuticals for enhancing cellular antioxidant defence mechanisms and improving health outcomes.

The Association between High-Dose Allopurinol and Erythropoietin Hyporesponsiveness in Advanced Chronic Kidney Disease: JOINT-KD Study

INTRODUCTION

The aim of the study was to explore the association between urate-lowering agents and reduced response to erythropoietin-stimulating agents in patients suffering from chronic kidney disease G5.

METHODS

We conducted a cross-sectional, multicenter study in Japan between April and June 2013, enrolling patients aged 20 years or older with an estimated glomerular filtration rate of ≤15 mL/min/1.73 m2. Exclusion criteria encompassed patients with a history of hemodialysis, peritoneal dialysis, or organ transplantation. The patients were categorized into four groups based on the use of urate-lowering drugs: high-dose allopurinol (>50 mg/day), low-dose allopurinol (≤50 mg/day), febuxostat, and no-treatment groups. We used a multivariable logistic regression model, adjusted for covariates, to determine the odds ratio (OR) for erythropoietin hyporesponsiveness, defined by an erythropoietin resistance index (ERI) of ≥10, associated with urate-lowering drugs.

RESULTS

A total of 542 patients were included in the analysis, with 105, 36, 165, and 236 patients in the high-dose allopurinol, low-dose allopurinol, febuxostat, and no-treatment groups, respectively. The median and quartiles of ERIs were 6.3 (0, 12.2), 3.8 (0, 11.2), 3.4 (0, 9.8), and 4.8 (0, 11.2) in the high-dose allopurinol, low-dose allopurinol, febuxostat, and no-treatment groups, respectively. The multivariate regression model showed a statistically significant association between the high-dose allopurinol group and erythropoietin hyporesponsiveness, compared to the no-treatment group (OR = 1.98, 95% confidence interval: 1.10-3.57).

CONCLUSIONS

Our study suggests that the use of high-dose allopurinol exceeding the optimal dose may lead to hyporesponsiveness to erythropoiesis-stimulating agents.

Peptide NCTX15 derived from spider toxin gland effectively relieves hyperuricemia in mice

Hyperuricemia is a clinical disease characterized by a continuous increase in uric acid (UA) due to purine metabolism disorder. As current drug treatments are limited, it is imperative to explore new drugs that offer better safety and efficacy. In this study, Nephila clavata toxin gland homogenates were isolated and purified by exclusion chromatography and high-performance liquid chromatography, resulting in the identification and isolation of a short peptide (NCTX15) with the sequence 'QSGHTFK'. Analysis showed that NCTX15 exhibited no cytotoxicity in mouse macrophages or toxic and hemolytic activity in mice. Notably, NCTX15 inhibited UA production by down-regulating urate transporter 1 and glucose transporter 9 and up-regulating organic anion transporter 1, thus promoting UA excretion. In addition, NCTX15 alleviated the inflammatory response and renal injury by inhibiting the expression of inflammatory factors interleukin-6, interleukin-1β, tumor necrosis factor alpha, NLR family, pyrin domain-containing 3, and pyroptosis-related factor gasdermin D. These results indicate that NCTX15 displayed urate-lowering, anti-inflammatory, and analgesic effects. As the first urate-reducing short peptide isolated from a spider toxin gland homogenate, NCTX15 exhibits considerable potential as a novel drug molecule for anti-gout and hyperuricemia treatment.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Raman Spectroscopy for the Quantitative Analysis of Solid Dosage Forms of the Active Pharmaceutical Ingredient of Febuxostat

Raman spectroscopy has been used to characterize and quantify the solid dosage forms of the commercially available drug febuxostat. For this purpose, different formulations consisting of the febuxostat (API) and excipients with different concentrations of the API are prepared and analyzed by Raman spectroscopy to identify different spectral features related to the febuxostat API and excipients. Multivariate data analysis tools such as principal component analysis (PCA) and partial least-squares regression (PLSR) analysis are used for qualitative and quantitative analyses. PCA has been found to be useful for the qualitative monitoring of various solid dosage forms. PLSR analysis has led to the successful prediction of API concentration in the unknown samples with a sensitivity and a selectivity of 98 and 99%, respectively. Moreover, the root-mean-square error (RMSE) of calibration and validation of the PLSR model has been found to be 2.9033 and 1.35, respectively. Notably, it is found to be very helpful for the comparison between the self-made formulations of febuxostat and commercially available febuxostat tablets (40 and 80 mg) of two different brands (Gouric and Zurig). These results showed that Raman spectroscopy can be a useful and reliable technique for identifying and quantifying the active pharmaceutical ingredient (API) in commercially available solid dosage forms.

Gout Treatment and Clinical Considerations: The Role of Pegloticase, Colchicine, and Febuxostat

Gout treatment has evolved rapidly in recent decades, and various drugs have been designed for acute and chronic management. Three medications used to treat gout include pegloticase, colchicine, and febuxostat. When prescribing these drugs, important factors to consider include pharmacokinetics, pharmacodynamics, population specifics, benefits, and contraindications. Pharmacokinetic considerations of each drug include absorption, distribution, metabolism, and elimination factors. Pharmacodynamics factors are assessed by their potential for toxicity and effects on serum uric acid levels. Additionally, the drug's targeted population must be considered to avoid unwanted complications in certain pre-existing conditions such as cardiovascular disease or glucose-6-dehydrogenase (G6PD) deficiency. In this paper, we aim to provide insight into the gout medications, pegloticase, colchicine, and febuxostat. This review will include their pharmacokinetics, pharmacodynamics, population specifics, benefits, and contraindications.

A Phase I Study to Evaluate the Pharmacokinetic Drug‒Drug Interaction of HP501, Febuxostat, and Colchicine in Male Chinese Patients with Hyperuricemia

BACKGROUND AND OBJECTIVE

HP501 is a highly selective renal urate transporter 1 (URAT1) inhibitor that is being developed for the treatment of hyperuricemia and gout. The primary aim of the present study was to study the pharmacokinetic drug‒drug interactions (DDIs) of HP501, febuxostat, and colchicine in hyperuricemic patients.

METHODS

Hyperuricemic patients were randomly divided into group A, receiving HP501 40 mg once daily on days 1 and 4-10, and group B, receiving febuxostat 40 mg once daily on day 1 and HP501 40 mg plus febuxostat 40 mg on days 4-10. All patients received 0.5 mg colchicine once daily from day 4 to 12. Blood samples were collected for measurement of drug concentrations and serum uric acid (sUA) levels.

RESULTS

Coadministration of colchicine with HP501 or HP501 plus febuxostat did not affect steady-state exposure to colchicine. Coadministration of HP501 and febuxostat did not significantly change the pharmacokinetic profiles of either drug. Following multiple administrations of HP501 40 mg once daily for 7 days, the maximal percent sUA change from baseline in group A was - 24.77%. The coadministration of HP501 40 mg and febuxostat 40 mg in group B for 7 days resulted in a - 55.82% maximal sUA reduction from baseline, and all patients achieved the goal of sUA < 360 μmol/L. All adverse events (AEs) were either mild or moderate, and the most frequently reported AEs were diarrhea and elevated alanine aminotransferase (ALT) levels.

CONCLUSIONS

The concomitant use of HP501, febuxostat, and colchicine did not produce clinically meaningful DDIs in terms of their pharmacokinetic properties.

CLINICAL TRIAL REGISTRATION

No. CTR20212261 ( http://www.chinadrugtrials.org.cn/ ) registered September 2021.

Amelioration effects of α-viniferin on hyperuricemia and hyperuricemia-induced kidney injury in mice

BACKGROUND

α-Viniferin, the major constituent of the roots of Caragana sinica (Buc'hoz) Rehder with a trimeric resveratrol oligostilbenoid skeleton, was demonstrated to possess a strong inhibitory effect on xanthine oxidase in vitro, suggesting it to be a potential anti-hyperuricemia agent. However, the in vivo anti-hyperuricemia effect and its underlying mechanism were still unknown.

PURPOSE

The current study aimed to evaluate the anti-hyperuricemia effect of α-viniferin in a mouse model and to assess its safety profile with emphasis on its protective effect on hyperuricemia-induced renal injury.

METHODS

The effects were assessed in a potassium oxonate (PO)- and hypoxanthine (HX)-induced hyperuricemia mice model by analyzing the levels of serum uric acid (SUA), urine uric acid (UUA), serum creatinine (SCRE), serum urea nitrogen (SBUN), and histological changes. Western blotting and transcriptomic analysis were used to identify the genes, proteins, and signaling pathways involved.

RESULTS

α-Viniferin treatment significantly reduced SUA levels and markedly mitigated hyperuricemia-induced kidney injury in the hyperuricemia mice. Besides, α-viniferin did not show any obvious toxicity in mice. Research into the mechanism of action of α-viniferin revealed that it not only inhibited uric acid formation by acting as an XOD inhibitor, but also reduced uric acid absorption by acting as a GLUT9 and URAT1 dual inhibitor as well as promoted uric acid excretion by acting as a ABCG2 and OAT1 dual activator. Then, 54 differentially expressed (log₂ FPKM ≥ 1.5, p ≤ 0.01) genes (DEGs) repressed by the treatment of α-viniferin in the hyperuricemia mice were identified in the kidney. Finally, gene annotation results revealed that downregulation of S100A9 in the IL-17 pathway, of CCR5 and PIK3R5 in the chemokine signaling pathway, and of TLR2, ITGA4, and PIK3R5 in the PI3K-AKT signaling pathway were involved in the protective effect of α-viniferin on the hyperuricemia-induced renal injury.

CONCLUSIONS

α-Viniferin inhibited the production of uric acid through down-regulation of XOD in hyperuricemia mice. Besides, it also down-regulated the expressions of URAT1 and GLUT9 and up-regulated the expressions of ABCG2 and OAT1 to promote the excretion of uric acid. α-Viniferin could prevent hyperuricemia mice from renal damage by regulating the IL-17, chemokine, and PI3K-AKT signaling pathways. Collectively, α-viniferin was a promising antihyperuricemia agent with desirable safety profile. This is the first report of α-viniferin as an antihyperuricemia agent.

Risk of Erectile Dysfunction in Male Patients with Gout Treated with Febuxostat or Allopurinol: A Propensity Score-Matched Cohort Study

OBJECTIVE

To evaluate and compare the risk of erectile dysfunction (ED) associated with the use of allopurinol and febuxostat in adult male gout patients.

METHODS

We conducted a cohort study using TriNetX (Cambridge, MA, USA), a global federated health research network that provides real-time electronic medical record datasets. We analyzed and compared the associated risk of ED in gout patients who started taking allopurinol or febuxostat within 12 months. Propensity score matching was performed to adjust for demographic variables, comorbidities, and medication use. Kaplan-Meier analysis was used to estimate the probability of the outcome of interest. The hazard ratio (HR) and associated confidence intervals were calculated along with the proportionality test using R's Survival Package v3.2-3.

RESULTS

We identified 679,862 patients with gout among 107,517,445 patients in the database. Of these patients, 24,000 were treated with febuxostat and 299,726 with allopurinol. After propensity matching, 9075 patients receiving febuxostat without allopurinol (febuxostat group) and 9075 corresponding patients receiving allopurinol without febuxostat (allopurinol group) were analyzed for comparison. Among all male patients over 19 years of age, febuxostat was associated with a significantly higher risk of ED versus allopurinol (HR 1.354; 95% confidence interval (CI) 1.003-1.829; log rank test, p = 0.047). After subgroup analysis, in gout patients aged 19-64 years, a significantly higher incidence of ED was observed in the febuxostat group than in the allopurinol group (HR 2.002, 95% CI 1.282-3.126). The risk of ED did not differ significantly between the allopurinol and febuxostat groups in gout patients older than 65 years.

CONCLUSIONS

Febuxostat may be associated with a higher risk of ED than allopurinol in adult male patients with gout. Future large-scale prospective studies are warranted to confirm our results.

Fabrication and In Vitro Evaluation of Febuxostat Tablet for Obtaining Biphasic Drug Release Profile

Aim and Objective The primary aim of the present investigation was to adopt the concept of quality by design (QbD) for developing Febuxostat matrix tablets containing a novel combination of polyethylene oxide (PEO), pre-gelatinized starch (PGS) and lactose for obtaining biphasic drug release. Experimental work Febuxostat-containing matrix tablets were prepared by direct compression using 32 full factorial designs. The tablets were prepared with varying amounts of PEO WSR 301 to PGS and lactose to obtain the desired release pattern. The chosen responses were cumulative % drug released at 1, 6 and 12 hours. The evaluation of tablets was done for pre and post-compressional parameters. Compared with the marketed tablet, the optimized formulations were selected based on in vitro drug release. Dose dumping was checked in the dissolution medium containing up to 40% alcohol. Result and discussion The results of the dissolution study indicated that the batch containing a 1:1 ratio of PEO WSR 301 and PGS (15 mg each) and 20 mg of Lactose showed fast initial drug release to imitate the pharmacological action followed by sustained drug release effect. The use of Lactose facilitated immediate drug release, while PEO WSR 301 and PGS exhibited the opposite effect on cumulative drug release. The results of the 32 Factorial design revealed that the concentration of Lactose is a critical parameter. Dose dumping was not observed in the alcoholic dissolution medium. Kinetic equations were fitted to the dissolution data after 1 hour of the dissolution study. Conclusion The type (soluble or swellable) and the concentration of excipients (low or high) dictate the tablets' drug release. The study's outcome revealed that the most critical material attribute is the amount of lactose. The novel combination of PEO, PGS and lactose can bypass existing patents and give more industrial applicability.

Novel Antibacterial Activity of Febuxostat, an FDA-Approved Antigout Drug against Mycobacterium tuberculosis Infection

Accumulating evidence suggests that drug repurposing has drawn attention as an anticipative strategy for controlling tuberculosis (TB), considering the dwindling drug discovery and development pipeline. In this study, we explored the antigout drug febuxostat and evaluated its antibacterial activity against Mycobacterium species. Based on MIC evaluation, we found that febuxostat treatment significantly inhibited mycobacterial growth, especially that of Mycobacterium tuberculosis (Mtb) and its phylogenetically close neighbors, M. bovis, M. kansasii, and M. shinjukuense, but these microorganisms were not affected by allopurinol and topiroxostat, which belong to a similar category of antigout drugs. Febuxostat concentration-dependently affected Mtb and durably mediated inhibitory functions (duration, 10 weeks maximum), as evidenced by resazurin microtiter assay, time-kill curve analysis, phenotypic susceptibility test, and the Bactec MGIT 960 system. Based on these results, we determined whether the drug shows antimycobacterial activity against Mtb inside murine bone marrow-derived macrophages (BMDMs). Notably, febuxostat markedly suppressed the intracellular growth of Mtb in a dose-dependent manner without affecting the viability of BMDMs. Moreover, orally administered febuxostat was efficacious in a murine model of TB with reduced bacterial loads in both the lung and spleen without the exacerbation of lung inflammation, which highlights the drug potency. Taken together, unexpectedly, our data demonstrated that febuxostat has the potential for treating TB.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

TRIAL REGISTRATION

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

Dosage individualization proposed for anti-gout medications among the patients with gout

BACKGROUND

The conventional one-size-fits-all approach has been criticized for almost all drugs used especially for chronic diseases, including gout. The present study was aimed to explore the need of individualization and optimization of the dose of anti-gout medications among gout patients.

METHODS

Cross-sectional study was carried out among 384 randomly selected new gout patients visiting two gout treatment centers at Lalitpur Metropolitan City, Nepal and who were taking antigout medications. Patients not taking anti-gout medications and not showing willingness to participate were excluded. The eGFR was calculated with the CKD Epidemiology Collaboration (CKD-EPI) creatinine equation (2009). Doses to be individualized were decided based on the Renal Drug Handbook and verified with the BNF 80. Data were analyzed via R 4.0.3 by applying the multinomial logistic regression to analyze statistical significance of risk with various predictors, and considering a p-value <0.05 statistically significant. Comorbidities were coded as per the ICD-11 coding and medicines were coded according to the WHO Guidelines for ATC classification and DDD assignment 2020.

RESULTS

The high risk of progression to CKD increased in the age range 54-63 and ≥84 years by 17.77 and 43.02 times, respectively. Also, high risk increased by 29.83 and 20.2 times for the overweight and the obese respectively. Aceclofenac 100mg was prescribed for maximum patients (30.5%). Need of dose individualization was realized in 30 patients, with maximum (7) in case of etoricoxib 90mg. Various glucocorticoids were prescribed for 36.9% patients, out of whom 3.8%required dose individualization and 15.9% patients with xanthine oxidase inhibitors, out of whom 1.3% required dose individualization.

CONCLUSION

Thirty cases required dose individualization, which was although minimal but could have meaningful impact on the clinical success of the individual patient. Based on the recommendation on dose individualization, those patients could be optimized on their therapy on future follow ups.

Febuxostat-based amides and some derived heterocycles targeting xanthine oxidase and COX inhibition. Synthesis, in vitro and in vivo biological evaluation, molecular modeling and in silico ADMET studies

Various febuxostat derivatives comprising carboxamide functionalities and different substituted heterocycles were synthesized and evaluated for their biological activities as xanthine oxidase (XO) and cyclooxygenase (COX) inhibitors. All the tested compounds exhibited variable in vitro XO inhibitory activities (IC₅₀ values 0.009-0.077 µM), among which the analog 17 has emerged as the most potent derivative (IC₅₀ 0.009 µM), representing nearly 3-times the potency of febuxostat (IC₅₀ 0.026 µM). The same analogs were further investigated for their in vitro COX-1 and COX-2 inhibitory activity, where fifteen analogs demonstrated recognizable COX-2 inhibitory potential (IC₅₀ values range 0.04 - 0.1 µM), when correlated with celecoxib (IC₅₀ 0.05 µM), together with appreciable selectivity indices. Compounds 5a, 14b, 17, 19c, 19e and 21b that showed significant in vitro XO and/ or COX inhibitory potentials were further investigated for their in vivo hypouricemic as well as anti-inflammatory activities. Interestingly, the in vivo results were concordant with the collected in vitro data. Docking of compounds 5a, 14b, 17, 19c, 19e and 21b with the active sites of XO and COX-2 isozymes demonstrated superior binding profile compared with the reported ligands (febuxostat and celecoxib, respectively). Their docking scores were reasonable and cohering to a great extent with their corresponding in vitro IC₅₀ values. Moreover, in silico computation of the predicted pharmacokinetic and toxicity properties (ADMET), together with the ligand efficiency (LE) of the same six compounds suggesting their liability to act as new orally active drug candidates with a predicted high safety profile.

Antihyperuricemic Effect of Urolithin A in Cultured Hepatocytes and Model Mice

Hyperuricemia is defined as a disease with high uric acid (UA) levels in the blood and a strong risk factor for gout. Urolithin A (UroA) is a main microbial metabolite derived from ellagic acid (EA), which occurs in strawberries and pomegranates. In this study, we evaluated antihyperuricemic effect of UroA in both cultured hepatocytes and hyperuricemic model mice. In cultured hepatocytes, UroA significantly and dose-dependently reduced UA production. In model mice with purine bodies-induced hyperuricemia, oral administration of UroA significantly inhibited the increase in plasma UA levels and hepatic xanthine oxidase (XO) activity. In addition, DNA microarray results exhibited that UroA, as well as allopurinol, a strong XO inhibitor, induced downregulation of the expression of genes associated with hepatic purine metabolism. Thus, hypouricemic effect of UroA could be, at least partly, attributed to inhibition of purine metabolism and UA production by suppressing XO activity in the liver. These results indicate UroA possesses a potent antihyperuricemic effect and it could be a potential candidate for a molecule capable of preventing and improving hyperuricemia and gout.

Pharmacogenomics in Asian Subpopulations and Impacts on Commonly Prescribed Medications

Asians as a group comprise > 60% the world's population. There is an incredible amount of diversity in Asian and admixed populations that has not been addressed in a pharmacogenetic context. The known pharmacogenetic differences in Asian subgroups generally represent previously known variants that are present at much lower or higher frequencies in Asians compared with other populations. In this review we summarize the main drugs and known genes that appear to have differences in their pharmacogenetic properties in certain Asian populations. Evidence-based guidelines and summary statistics from the US Food and Drug Administration and the Clinical Pharmacogenetics Implementation Consortium were analyzed for ethnic differences in outcomes. Implicated drugs included commonly prescribed drugs such as warfarin, clopidogrel, carbamazepine, and allopurinol. The majority of these associations are due to Asians more commonly being poor metabolizers of cytochrome P450 (CYP) 2C19 and carriers of the human leukocyte antigen (HLA)-B*15:02 allele. The relative risk increase was shown to vary between genes and drugs, but could be > 100-fold higher in Asians. Specifically, there was a 172-fold increased risk of Stevens-Johnson syndrome and toxic epidermal necrolysis with carbamazepine use among HLA-B*15:02 carriers. The effects ranged from relatively benign reactions such as reduced drug efficacy to severe cutaneous skin reactions. These reactions are severe and prevalent enough to warrant pharmacogenetic testing and appropriate changes in dose and medication choice for at-risk populations. Further studies should be done on Asian cohorts to more fully understand pharmacogenetic variants in these populations and to clarify how such differences may influence drug response.

Xanthine oxidase inhibition attenuates insulin resistance and diet-induced steatohepatitis in mice

Hyperuricemia drives the development of nonalcoholic fatty liver disease (NAFLD). Pharmacological inhibition of xanthine oxidase (XO), a rate-limiting enzyme for uric acid (UA) production, has been demonstrated to improve hepatic steatosis in diet-induced obese mice. However, it remains unclear whether inhibition of XO improves nonalcoholic steatohepatitis (NASH), a more advanced form of NAFLD, in terms of both liver inflammation and fibrosis. Here, we investigated the effects of febuxostat and allopurinol, two XO inhibitors clinically used for gout, on a mouse model of NASH. Furthermore, we conducted a single-arm, open-label intervention study with febuxostat for NAFLD patients with hyperuricemia. Despite a similar hypouricemic effect of the XO inhibitors on blood UA level, febuxostat, but not allopurinol, significantly decreased hepatic XO activity and UA levels in the NASH model mice. These reductions in hepatic XO activity and UA levels were accompanied by attenuation of insulin resistance, lipid peroxidation, and classically activated M1-like macrophage accumulation in the liver. Furthermore, in NAFLD patients with hyperuricemia, treatment with febuxostat for 24 weeks decreased the serum UA level, accompanied by reductions in the serum levels of liver enzymes, alanine aminotransferase and aspartate aminotransferase. XO may represent a promising therapeutic target in NAFLD/NASH, especially in patients with hyperuricemia.

Febuxostat is superior to allopurinol in delaying the progression of renal impairment in patients with chronic kidney disease and hyperuricemia

PURPOSE

This study aimed to compare efficacy of renal-protective function between febuxostat and allopurinol in patients with chronic kidney disease (CKD) and hyperuricemia (HUA).

METHODS

Totally 152 CKD stage 2-3 patients complicated with HUA were recruited. According to their uric acid-lowering therapy, there were 67 patients included in febuxostat group and 85 in allopurinol group, respectively. Estimated glomerular filtration rate (eGFR), serum creatinine (Scr), 24-h proteinuria, serum uric acid (SUA) were measured at M0, M1, M3 and M6 after the treatment. Primary outcome was proportion of patients showing ≥ 10% decline in eGFR from baseline at M6.

RESULTS

The eGFR at M6 was numerically higher at M6 and eGFR change (M6-M0) was increased in febuxostat group compared with allopurinol group. Most importantly, the proportion of patients showing a ≥ 10% decline in eGFR from baseline at M6 was reduced in febuxostat group compared with allopurinol group. Multivariate logistic regression analyses further validated that febuxostat vs. allopurinol was an independent predictor for reduced risk of eGFR decline ≥ 10% from baseline. Besides, SUA change (M6-M0) was decreased, but Scr change (M6-M0) and 24-h proteinuria change (M6-M0) were similar in febuxostat group compared with allopurinol group.

CONCLUSIONS

Febuxostat presents a superior effect in delaying renal impairment progression compared with allopurinol in CKD patients complicated with HUA.

Urate-lowering agents for asymptomatic hyperuricemia in stage 3 - 4 chronic kidney disease: Controversial role of kidney function

Because the serum uric acid level increases as the glomerular filtration rate (GFR) decreases, hyperuricemia is associated with chronic kidney disease (CKD). Although hyperuricemia is a risk factor for CKD progression, the causal role of uric acid remains controversial in patients with CKD and asymptomatic hyperuricemia. This study included 588 patients with stage 3-4 CKD and asymptomatic hyperuricemia. Using propensity score matching, 165 pairs treated and untreated with pharmacologic urate-lowering therapy were matched. Kaplan-Meier curves were constructed to determine the effect of urate-lowering agents on kidney survival. The prognostic value for kidney survival was ascertained using Cox regression analysis. The GFR changes over time between the patients treated and untreated with urate-lowering agents were assessed using a linear mixed model analysis. The mean age of the matched patients was 63.2 ± 12.7 years, and 52 (15.8%) patients had diabetic nephropathy. The mean estimated GFR (eGFR) and serum uric acid level were 36.7 mL/min/1.73 m2 and 7.8 mg/dL, respectively. During a mean follow-up period of 41.9 months, 87 developed end-stage kidney disease (ESKD). The incidence rates of ESKD were comparable between the patients treated and untreated with urate-lowering agents. The Kaplan-Meier analysis indicated that kidney survival was also comparable between them. In the multivariate analysis, heart failure and low eGFR were the significant prognostic factors for kidney survival. However, pharmacologic urate-lowering therapy was not predictive of kidney survival. The overall GFR decline rate was also comparable between the groups (P = 0.13). The efficacy of pharmacologic urate-lowering therapy in delaying CKD progression remains controversial. Therefore, further randomized controlled trials are needed to confirm its efficacy in attenuating kidney function deterioration in patients with stage 3-4 CKD.

Role of Molybdenum-Containing Enzymes in the Biotransformation of the Novel Ghrelin Receptor Inverse Agonist PF-5190457: A Reverse Translational Bed-to-Bench Approach

(R)-2-(2-methylimidazo[2,1-b]thiazol-6-yl)-1-(2-(5-(6-methylpyrimidin-4-yl)-2,3-dihydro-1H-inden-1-yl)-2,7-diazaspiro[3.5]nonan-7-yl)ethan-1-one (PF-5190457) was identified as a potent and selective inverse agonist of the ghrelin receptor [growth hormone secretagogue receptor 1a (GHS-R1a)]. The present translational bed-to-bench work characterizes the biotransformation of this compound in vivo and then further explores in vitro metabolism in fractions of human liver and primary hepatocytes. Following oral administration of PF-5190457 in a phase 1b clinical study, hydroxyl metabolites of the compound were observed, including one that had not been observed in previously performed human liver microsomal incubations. PF-6870961 was biosynthesized using liver cytosol, and the site of hydroxylation was shown to be on the pyrimidine using nuclear magnetic resonance spectroscopy. The aldehyde oxidase (AO) inhibitor raloxifene and the xanthine oxidase inhibitor febuxostat inhibited the formation of PF-6870961 in human liver cytosol, suggesting both enzymes were involved in the metabolism of the drug. However, greater inhibition was observed with raloxifene, indicating AO is a dominant enzyme in the biotransformation. The intrinsic clearance of the drug in human liver cytosol was estimated to be 0.002 ml/min per milligram protein. This study provides important novel information at three levels: 1) it provides additional new information on the recently developed novel compound PF-5190457, the first GHS-R1a blocker that has moved to development in humans; 2) it provides an example of a reverse translational approach where a discovery in humans was brought back, validated, and further investigated at the bench level; and 3) it demonstrates the importance of considering the molybdenum-containing oxidases during the development of new drug entities. SIGNIFICANCE STATEMENT: PF-5190457 is a novel ghrelin receptor inverse agonist that is currently undergoing clinical development for treatment of alcohol use disorder. PF-6870961, a major hydroxyl metabolite of the compound, was observed in human plasma, but was absent in human liver microsomal incubations. PF-6870961 was biosynthesized using liver cytosol, and the site of hydroxylation on the pyrimidine ring was characterized. Inhibitors of aldehyde oxidase and xanthine oxidase inhibited the formation of PF-6870961 in human liver cytosol, suggesting both enzymes were involved in the metabolism of the drug. This information is important for patient selection in subsequent clinical studies.

Comparison of renoprotective effects of febuxostat and allopurinol in hyperuricemic patients with chronic kidney disease

PURPOSE

This study aimed to compare the renoprotective effect between febuxostat and allopurinol in hyperuricemic patients with chronic kidney disease (CKD), about which limited data are available.

METHODS

141 patients with stage 3 CKD and hyperuricemia were followed from June 2005 to April 2018. Thirty patients received febuxostat, 40 allopurinol and 71 conventional CKD management only (control group). We compared the mean serum uric acid levels, estimated glomerular filtration rate (eGFR) changes over time and renal survival time free from predefined renal disease progression among these 3 groups.

RESULTS

Overall, mean age was 62.6 ± 13.3 years, baseline eGFR 42.1 ± 8.8 mL/min/1.73 m², and serum uric acid 8.6 ± 1.5 mg/dL without intergroup difference. During the observation period (55.9 ± 31.8 months), febuxostat group, compared to both allopurinol and control group, had significantly lower mean serum uric acid levels (5.7 ± 1.0 vs. 7.1 ± 1.2 vs. 8.0 ± 0.8 mg/dL, p < 0.001) and maintained significantly higher mean eGFR values consistently for 4 years. Febuxostat group had significantly longer renal survival time free from renal disease progression than allopurinol and control group (87.7 (95% CI 71.2-104.2) vs. 77.6 (95% CI 60.2-94.9) vs. 48.7 (95% CI 39.3-58.1) months, respectively, p < 0.001). Cox proportional hazard model analysis adjusting for potent confounders revealed that febuxostat, with control group as reference, significantly reduced the risk of renal disease progression by 74.3% (hazard ratio 0.257 (95% CI 0.072-0.912), p = 0.036), while allopurinol showed insignificant result.

CONCLUSIONS

Febuxostat seems to reduce serum uric acid level and to retard renal disease progression more effectively than allopurinol in hyperuricemic patients with CKD.

Managing Tumor Lysis Syndrome in the Era of Novel Cancer Therapies

Abstract Tumor lysis syndrome (TLS) is a potentially life-threatening emergency that can develop rapidly after the release of intracellular contents from lysed malignant cells. The advent of novel and targeted therapies that have improved tumor-killing efficacy has the potential to increase the risk of TLS when used as part of front-line therapy. A recent review of TLS risk in patients with hematologic malignancies treated with newer targeted agents highlighted the need to revisit TLS risk stratification and to describe the practical challenges of TLS prevention, treatment, and monitoring. Although this era of rapid development of novel cancer therapies provides new hope for patients with hematologic malignancies, it is essential to be prepared for TLS because monitoring and prophylaxis can almost always prevent severe and life-threatening consequences. Heightened awareness of the development of TLS with novel and targeted agents, accompanied by aggressive hydration and rational, risk-appropriate management, are the keys to successful outcomes.

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.

A case series of allopurinol-induced toxic epidermal necrolysis

This is a case series of allopurinol-induced toxic epidermal necrolysis. Revisiting the indications of using allopurinol in asymptomatic hyperuricemia and a critical reappraisal of the safety profile of allopurinol is done in this article. The report is based on case presented at a tertiary hospital in Singapore. The aim of this study is to highlight the fatal consequences of the indiscriminate use of allopurinol. We report four cases of toxic epidermal necrolysis from allopurinol, three of which resulted in death. Our aim is to highlight that allopurinol in all these cases was not indicated and prescribed for asymptomatic hyperuricemia. The incidence and potentially severe and lethal consequences of allopurinol hypersensitivity syndrome and toxic epidermal necrolysis could be kept to a minimum by strictly adhering to the established indications of allopurinol treatment.

Gout. Novel therapies for treatment of gout and hyperuricemia

In the past few decades, gout has increased not only in prevalence, but also in clinical complexity, the latter accentuated in part by a dearth of novel advances in treatments for hyperuricemia and gouty arthritis. Fortunately, recent research reviewed here, much of it founded on elegant translational studies of the past decade, highlights how gout can be better managed with cost-effective, well-established therapies. In addition, the advent of both new urate-lowering and anti-inflammatory drugs, also reviewed here, promises for improved management of refractory gout, including in subjects with co-morbidities such as chronic kidney disease. Effectively delivering improved management of hyperuricemia and gout will require a frame shift in practice patterns, including increased recognition of the implications of refractory disease and frequent noncompliance of patients with gout, and understanding the evidence basis for therapeutic targets in serum urate-lowering and gouty inflammation.