Review of Urate-Lowering Therapeutics: From the Past to the Future

Food-derived bioactive peptides with anti-hyperuricemic activity: A comprehensive review

Hyperuricemia (HU) is a metabolic disorder caused by the overproduction or underexcretion of uric acid (UA) in the human body. Several approved drugs for the treatment of HU are available in the market; however, all these allopathic drugs exhibit multiple side effects. Therefore, the development of safe and effective anti-HU drugs is an urgent need. Natural compounds derived from foods and plants have the potential to decrease UA levels. Recently, food-derived bioactive peptides (FBPs) have gained attention as a functional ingredient owing to their biological activities. In the current review, we aim to explore the urate-lowering potential and the underlying mechanisms of FBPs. We found that FBPs mitigate HU by reducing blood UA levels through inhibiting key enzymes such as xanthine oxidase, increasing renal UA excretion, inhibiting renal UA reabsorption, increasing anti-oxidant activities, regulating inflammatory mediators, and addressing gut microbiota dysbiosis. In conclusion, FBPs exhibit strong potential to ameliorate HU.

Biomimetic Integrated Nanozyme for Flare and Recurrence of Gouty Arthritis

Flare and multiple recurrences pose significant challenges in gouty arthritis. Traditional treatments provide temporary relief from inflammation but fail to promptly alleviate patient pain or effectively prevent subsequent recurrences. It should also be noted that both anti-inflammation and metabolism of uric acid are necessary for gouty arthritis, calling for therapeutic systems to achieve these two goals simultaneously. In this study, we propose a biomimetic integrated nanozyme, HMPB-Pt@MM, comprising platinum nanozyme and hollow Prussian blue. It demonstrates anti-inflammatory properties by eliminating reactive oxygen species and reducing infiltration of inflammatory macrophages. Additionally, it rapidly targets inflamed ankles through the camouflage of macrophage membranes. Furthermore, HMPB-Pt@MM exhibits urate oxidase-like capabilities, continuously metabolizing locally elevated uric acid concentrations, ultimately inhibiting multiple recurrences of gouty arthritis. In summary, HMPB-Pt@MM integrates ROS clearance with uric acid metabolism, offering a promising platform for the treatment of gouty arthritis.

Large-scale cross-ancestry genome-wide meta-analysis of serum urate

Hyperuricemia is an essential causal risk factor for gout and is associated with cardiometabolic diseases. Given the limited contribution of East Asian ancestry to genome-wide association studies of serum urate, the genetic architecture of serum urate requires exploration. A large-scale cross-ancestry genome-wide association meta-analysis of 1,029,323 individuals and ancestry-specific meta-analysis identifies a total of 351 loci, including 17 previously unreported loci. The genetic architecture of serum urate control is similar between European and East Asian populations. A transcriptome-wide association study, enrichment analysis, and colocalization analysis in relevant tissues identify candidate serum urate-associated genes, including CTBP1, SKIV2L, and WWP2. A phenome-wide association study using polygenic risk scores identifies serum urate-correlated diseases including heart failure and hypertension. Mendelian randomization and mediation analyses show that serum urate-associated genes might have a causal relationship with serum urate-correlated diseases via mediation effects. This study elucidates our understanding of the genetic architecture of serum urate control.

Association between serum uric acid levels and lung function in the NHANES cohort (2007-2012): A cross-sectional analysis of a diverse American population

BACKGROUND

Hyperuricemia has been linked to various health conditions. However, the relationship between uric acid (UA) levels and lung function remains debated.

METHODS

In a cross-sectional study of 6750 participants aged 20-69 from NHANES, we assessed UA levels and lung function (FVC and FEV1). We conducted regression analyses while adjusting for potential confounders.

RESULTS

After accounting for factors like age, sex, BMI, smoking, and more, we found a negative association between UA FVC and FEV1. Specifically, for every 0.1 mg/dL increase in UA, FEV1 decreased by 15.265 mL, and FVC decreased by 24.46 mL. No association was observed with FEV1/FVC. Subgroup analyses revealed similar negative correlations among various groups, particularly in non-Hispanic Black females under 60.

CONCLUSION

Serum UA levels are inversely associated with FEV1 and FVC in the American population, with a notable impact on non-Hispanic Black females under 60.

Triterpenes Drug Delivery Systems, a Modern Approach for Arthritis Targeted Therapy

Arthritis is a major cause of disability. Currently available anti-arthritic drugs, such as disease-modifying anti-rheumatic drugs (DMARDs), have serious side-effects associated with long-term use. Triterpenoids are natural products with known anti-inflammatory properties, and many have revealed efficiency against arthritis both in vitro and in vivo in several animal models, with negligible cytotoxicity. However, poor bioavailability due to low water solubility and extensive metabolism upon oral administration hinder the therapeutic use of anti-arthritic triterpenoids. Therefore, drug delivery systems (DDSs) able to improve the pharmacokinetic profile of triterpenoids and achieve sustained drug release are useful alternatives for targeted delivery in arthritis treatment. Several DDSs have been described in the literature for triterpenoid delivery, including microparticulate and nanoparticulate DDSs, such as polymeric micro and nanoparticles (NPs), polymeric micelles, liposomes, micro and nanoemulsions, and hydrogels. These systems have shown superior therapeutic effects in arthritis compared to the free drugs and are similar to currently available anti-arthritic drugs without significant side-effects. This review focuses on nanocarriers for triterpenoid delivery in arthritis therapy, including osteoarthritis (OA), rheumatoid arthritis (RA) and gout that appeared in the literature in the last ten years.

Systematic review and model-based analysis to identify whether renal safety risks of URAT1 inhibitors are fully determined by uric acid-lowering efficacies

OBJECTIVE

Renal safety risk is currently an important factor that hinders the development of uric acid transporter 1 (URAT1) inhibitors. This study aimed to compare the renal safety and uric acid-lowering efficacy of different URAT1 inhibitors and clarify the association between them.

METHODS

A systematic review of published randomized controlled trials on URAT1 inhibitors was conducted to investigate the incidence of renal safety events. A model-based analysis was performed to predict the uric acid-lowering efficacy of representative URAT1 inhibitors.

RESULTS

The overall renal safety event incidences of lesinurad, verinurad, dotinurad, SHR4640, and benzbromarone in patients with hyperuricemia were 11.2 % (142/1264), 12.0 % (34/284), 0.5 % (2/421), 2.3 % (5/213), and 1.3 % (5/393), respectively. A semi-mechanistic pharmacokinetic/pharmacodynamic model was used to establish the dose-exposure-effect relationship of lesinurad, verinurad, dotinurad, and SHR4640 with or without the combination of xanthine oxidase inhibitors (XOIs). The efficacy ranking of the intermediate dose of URAT1 inhibitors with once-daily dosing was 2 mg dotinurad > 10 mg verinurad > 5 mg SHR4640 > 400 mg lesinurad. The combination of 80 mg febuxostat and 600 mg allopurinol reduced the 24-h cumulative renal uric acid excretion by 48.4 % and 48.3 %, respectively.

CONCLUSION

Uric acid-lowering efficacy is not an independent factor for the renal safety risk of different URAT1 inhibitors, and structural differences could be responsible for the difference. The adverse renal effects of URAT1 inhibitors are dose-dependent, and the combination with high doses of XOIs can significantly reduce the renal safety risk by reducing uric acid excretion by the kidneys.

Potentiation of the Uricosuric Effect of Dotinurad by Trans-Inhibition of the Uric Acid Reabsorptive Transporter 1

Urate transporter 1 (URAT1) is a transporter responsible for uric acid (UA) reabsorption by renal proximal tubules and a pharmacological target of uricosuric agents. Probenecid and benzbromarone have been used as uricosuric agents, while dotinurad was recently approved in Japan. Notably, the in vitro IC 50 of dotinurad on URAT1 is not strong enough to explain its in vivo uricosuric effect estimated based on clinical unbound plasma concentrations, suggesting the presence of mechanisms other than competition with UA uptake at the extracellular domain of URAT1 (cis-inhibition). In this study, trans-inhibition was hypothesized as the mechanism underlying URAT1 inhibition by dotinurad, wherein intracellularly accumulated dotinurad inactivates URAT1. In URAT1-expressing Madin-Darby Canine Kidney-II cells and Xenopus oocytes, pre-incubation with dotinurad potentiated the inhibitory effect more than co-incubation alone, but this effect was not observed with benzbromarone or probenecid. Under co-incubation, dotinurad inhibited UA uptake in a competitive manner (cis-inhibition). When we pre-injected dotinurad directly into oocytes and immediately measured [14C]UA uptake without coincubation (only trans-inhibition), dotinurad noncompetitively inhibited UA uptake. URAT1 is an exchange transporter for UA and monocarboxylates such as nicotinic acid (NA). Pre-injected dotinurad and extracellular UA attenuated and facilitated efflux of [3H]NA, respectively, whereas pre-injection of benzbromarone or probenecid did not affect it, suggesting that dotinurad exhibits trans-inhibition by attenuating URAT1-mediated efflux of monocarboxylates, which is a driving force for UA uptake by URAT1. Accordingly, dotinurad ameliorates URAT1-mediated UA reabsorption by both cis- and trans-inhibition, explaining its clinically stronger uricosuric effect than that estimated by the in vitro IC50 value. SIGNIFICANCE STATEMENT: The uricosuric agent dotinurad inhibits uric acid reabsorptive transporter (URAT) 1 with a clinical potency stronger than that estimated from IC 50 obtained by in vitro URAT1 inhibition. This in vivo-in vitro discrepancy was explained by the trans-inhibition effect of dotinurad on URAT1. Trans-inhibition was due to the attenuation of monocarboxylates efflux via URAT1, which is a driving force for URAT1-mediated exchange transport of uric acid. Overall, this is the first study to experimentally demonstrate trans-inhibition mechanism of URAT1.

Emerging Urate-Lowering Drugs and Pharmacologic Treatment Strategies for Gout: A Narrative Review

Hyperuricemia with consequent monosodium urate crystal deposition leads to gout, characterized by painful, incapacitating inflammatory arthritis flares that are also associated with increased cardiovascular event and related mortality risk. This narrative review focuses on emerging pharmacologic urate-lowering treatment (ULT) and management strategies in gout. Undertreated, gout can progress to palpable tophi and joint damage. In oral ULT clinical trials, target serum urate of < 6.0 mg/dL can be achieved in ~ 80-90% of subjects, with flare burden reduction by 1-2 years. However, real-world ULT results are far less successful, due to both singular patient nonadherence and prescriber undertreatment, particularly in primary care, where most patients are managed. Multiple dose titrations commonly needed to optimize first-line allopurinol ULT monotherapy, and substantial potential toxicities and other limitations of approved, marketed oral monotherapy ULT drugs, promote hyperuricemia undertreatment. Common gout comorbidities with associated increased mortality (e.g., moderate-severe chronic kidney disease [CKD], type 2 diabetes, hypertension, atherosclerosis, heart failure) heighten ULT treatment complexity and emphasize unmet needs for better and more rapid clinically significant outcomes, including attenuated gout flare burden. The gout drug armamentarium will be expanded by integrating sodium-glucose cotransporter-2 (SGLT2) inhibitors with uricosuric and anti-inflammatory properties as well as clinically indicated antidiabetic, nephroprotective, and/or cardioprotective effects. The broad ULT developmental pipeline is loaded with multiple uricosurics that selectively target uric acid transporter 1 (URAT1). Evolving ULT approaches include administering selected gut anaerobic purine degrading bacteria (PDB), modulating intestinal urate transport, and employing liver-targeted xanthine oxidoreductase mRNA knockdown. Last, emerging measures to decrease the immunogenicity of systemically administered recombinant uricases should simplify treatment regimens and further improve outcomes in managing the most severe gout phenotypes.

Gout therapeutics and drug delivery

Gout is a common inflammatory arthritis caused by persistently elevated uric acid levels. With the improvement of people's living standards, the consumption of processed food and the widespread use of drugs that induce elevated uric acid, gout rates are increasing, seriously affecting the human quality of life, and becoming a burden to health systems worldwide. Since the pathological mechanism of gout has been elucidated, there are relatively effective drug treatments in clinical practice. However, due to (bio)pharmaceutical shortcomings of these drugs, such as poor chemical stability and limited ability to target the pathophysiological pathways, traditional drug treatment strategies show low efficacy and safety. In this scenario, drug delivery systems (DDS) design that overcome these drawbacks is urgently called for. In this review, we initially describe the pathological features, the therapeutic targets, and the drugs currently in clinical use and under investigation to treat gout. We also comprehensively summarize recent research efforts utilizing lipid, polymeric and inorganic carriers to develop advanced DDS for improved gout management and therapy.

Development of a novel anti-inflammatory recombinant uricase with extended half-life for gout therapy

Gout is a form of inflammatory arthritis that results from elevated serum uric acid levels and the deposition of urate crystals in multiple joints. The inflammatory response during an acute gout attack is mediated by the activation of the NLRP3 inflammasome, leading to the release of IL-1β and inducing a localized tissue inflammatory response. Urate lowering therapies such as Pegloticase effectively reduce serum uric acid levels but are generally associated with an increase in acute gout flares. In this study, we developed a long-acting anti-inflammatory recombinant uricase by sequential fusing interleukin-1 receptor antagonist (IL-1Ra) and albumin-binding domain (ABD) with the N-terminal end of Arthrobacter globiformis uricase (AgUox). The recombinant uricase has longer in vivo half-life, and significantly alleviates monosodium urate (MSU) crystals induced inflammation in mouse model compared with the wild-type AgUox. This long-acting anti-inflammatory recombinant uricase has the potential to be developed as an effective urate lowering therapy with better safety profiles.

The Singapore Experience With Uncontrolled Gout: Unmet Needs in the Management of Patients

Gout is the most common type of inflammatory arthritis, and its impact on cardiovascular health and quality of life is often underestimated. The prevalence and incidence of gout are increasing globally. Further, ischemic heart disease (IHD) and chronic kidney disease (CKD) are prevalent in gout patients. Some unmet needs for gout management include physicians' low initiation rate of urate-lowering therapy (ULT) and poor treatment adherence in patients with gout. There is also a lack of randomized controlled trials that establish safe doses of acute and long-term treatment for gout, particularly in patients with IHD and stage 4 CKD and above (including end-stage renal failure). Furthermore, there is also a lack of studies showing optimal serum uric acid (SUA) target and validated clinical outcome measures, including disease activity and remission criteria for gout tailored to treat-to-target approaches and the high cost of newer gout medications. The causal relationship between asymptomatic hyperuricemia or gout with comorbidities such as IHD and CKD has yet to be fully elucidated. There is a pressing need for collaborative international efforts to address the overall suboptimal management of gout.

Comparative Study of the Lipophilicity of Selected Anti-Androgenic and Blood Uric Acid Lowering Compounds

This study aimed to evaluate the lipophilicity of a series substances lowering the concentration of uric acid in blood and anti-androgen drugs by thin-layer chromatography in reversed-phase systems (RP-TLC, RP-HPTLC) and computational methods. The chromatographic parameter of lipophilicity (R_MW) of tested compounds was determined on three stationary phases, i.e., RP18F₂₅₄, RP18WF₂₅₄ and RP2F₂₅₄, using ethanol-water, propan-2-ol-water and acetonitrile-water in various volume compositions as mobile phases. The chromatographic analysis led to determining the experimental value of the lipophilicity parameter for each of the tested compounds, including those for which the experimental value of the partition coefficient (logP_exp) as a measure of lipophilicity is not well described in available databases, such as febuxostat, oxypurinol, ailanthone, abiraterone and teriflunomide. The chromatographic parameters of lipophilicity were compared with the logP values obtained with various software packages, such as AClogP, AlogPs, AlogP, MlogP, XlogP2, XlogP3, ACD/logP and logP_KOWWIN. The obtained results indicate that, among selected chromatographic parameters of lipophilicity, both experimental and calculated logP values gave similar results, and these RP-TLC or RP-HPTLC systems can be successfully applied to estimate the lipophilicity of studied heterocyclic compounds belonging to two different pharmacological groups. This work also illustrates the similarity and difference existing between the tested compounds under study using the chemometric methods, such as principal component analysis (PCA) and cluster analysis (CA). In addition, a relatively new approach based on the sum of ranking differences (SRD) was used to compare the chromatographically obtained and theoretical lipophilicity descriptors of studied compounds.

Improved joint and patient-reported health assessments with pegloticase plus methotrexate co-therapy in patients with uncontrolled gout: 12-month exploratory outcomes of the MIRROR open-label trial

BACKGROUND

Uncontrolled/refractory gout patients are recalcitrant/intolerant to oral urate-lowering therapies (ULTs), experiencing frequent gout flares, functionally limiting tophi, and low quality of life. Pegloticase lowers urate, but anti-pegloticase antibodies limit urate-lowering efficacy and increase infusion reaction (IR) risk. Immunomodulator + pegloticase co-administration may improve treatment response rates, with 79% of MIRROR open-label trial (MIRROR-OL, pegloticase + oral methotrexate) participants meeting 6-month response criteria. Exploratory outcomes from MIRROR-OL are described here.

METHODS

Adults with uncontrolled gout (serum urate [SU] ≥ 6 mg/dL and ULT-intolerance/recalcitrance or functionally limiting tophi) were included. Oral methotrexate (15 mg/week) was administered 4 weeks before and during pegloticase treatment (biweekly 8 mg infusion, ≤ 52 weeks). Exploratory outcomes included change from baseline (CFB) in number of affected joints, Health Assessment Questionnaires (HAQs), and Gout Global Assessments.

RESULTS

Fourteen patients received ≥ 1 pegloticase infusion, with 13 included in 52-week analyses (1 enrolled before treatment-extension amendment, exited at 24 weeks). Three patients prematurely exited due to SU rise; 10 completed 52-week evaluations (8 completed 52 weeks of co-therapy, 2 completed 24 weeks [met treatment goals]). At 52 weeks, SU averaged 1.1 ± 2.5 mg/dL, with improvements in HAQ pain and health (CFB: - 33.6 and - 0.7, respectively), Patient and Physician Global Assessments (CFB: - 4.6 and - 5.7, respectively), and joint involvement (CFB: - 5.6, - 8.4, - 6.0 tender, swollen, tophi-affected joints, respectively). Two patients underwent dual-energy computed tomography, showing concomitant monosodium urate volume reductions. All patients had ≥ 1 AE, with 92.9% experiencing acute flare. One mild IR ("cough") occurred and no new safety signals were identified.

CONCLUSION

Pegloticase + methotrexate co-therapy resulted in sustained SU-lowering with meaningful improvements in clinical measures, urate burden, and patient-reported outcomes.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT03635957).