Refractory gout: what is it and what to do about it?

Patient Experience with Chronic Refractory Gout and Its Impact on Health-Related Quality of Life: Literature Review and Qualitative Analysis

INTRODUCTION

Patients with chronic refractory gout face a considerable burden of disease due to unexpected flares characterized by severe and debilitating pain, which can lead to chronic pain and joint damage. This study aimed to understand the symptoms and impacts of chronic refractory gout on health-related quality of life (HRQoL).

METHODS

A targeted literature review was conducted to identify and review key articles describing the symptoms and impacts of gout, and articles examining the psychometric performance of the Medical Outcomes Survey Short Form-36 (SF-36) and Health Assessment Questionnaire-Disability Index (HAQ-DI) in gout. Qualitative interviews were conducted with 20 participants with chronic refractory gout. The results were used to develop the conceptual model and determine the appropriateness of the SF-36 and HAQ-DI in evaluating HRQoL in this population.

RESULTS

Most frequently reported symptoms included bodily pain (n = 18, 90.0%), joint swelling (n = 18, 90.0%), joint tenderness (n = 18, 90.0%), and joint pain (n = 16, 80.0%). Most frequently reported impacts were difficulties climbing a flight (n = 20, 100.0%) or several flights of stairs (n = 20, 100.0%), climbing five steps (n = 19, 95.0%), completing chores (n = 19, 95.0%), and running errands and shopping (n = 19, 95.0%). All assessed items from SF-36 and HAQ-DI were reported by ≥ 25% (n = 5) of participants and mapped sufficiently to concepts elicited by participants.

CONCLUSIONS

Patients with chronic refractory gout report symptoms and impacts that are highly bothersome and burdensome to everyday life. Items included in the HAQ-DI and SF-36 mapped directly to these symptoms and impacts and are relevant to understand the burden of disease of chronic refractory gout.

Traditional herbal medicine: Therapeutic potential in acute gouty arthritis

ETHNOPHARMACOLOGICAL RELEVANCE

Acute gouty arthritis (AGA) is characterized by a rapid inflammatory reaction caused by the build-up of monosodium urate (MSU) crystals in the tissues surrounding the joints. This condition often associated with hyperuricemia (HUA), is distinguished by its symptoms of intense pain, active inflammation, and swelling of the joints. Traditional approaches in AGA management often fall short of desired outcomes in clinical settings. However, recent ethnopharmacological investigations have been focusing on the potential of Traditional Herbal Medicine (THM) in various forms, exploring their therapeutic impact and targets in AGA treatment.

AIM OF THE REVIEW

This review briefly summarizes the current potential pharmacological mechanisms of THMs - including active ingredients, extracts, and prescriptions -in the treatment of AGA, and discusses the relevant potential mechanisms and molecular targets in depth. The objective of this study is to offer extensive information and a reference point for the exploration of targeted AGA treatment using THMs.

MATERIALS AND METHODS

This review obtained scientific publications focused on in vitro and in vivo studies of anti-AGA THMs conducted between 2013 and 2023. The literature was collected from various journals and electronic databases, including PubMed, Elsevier, ScienceDirect, Web of Science, and Google Scholar. The retrieval and analysis of relevant articles were guided by keywords such as "acute gouty arthritis and Chinese herbal medicine," "acute gouty arthritis herbal prescription," "acute gouty arthritis and immune cells," "acute gouty arthritis and inflammation," "acute gouty arthritis and NOD-like receptor thermoprotein domain associated protein 3 (NLRP3)," "acute gouty arthritis and miRNA," and "acute gouty arthritis and oxidative stress."

RESULTS

We found that AGA has a large number of therapeutic targets, highlighting the effectiveness the potential of THMs in AGA treatment through in vitro and in vivo studies. THMs and their active ingredients can mitigate AGA symptoms through a variety of therapeutic targets, such as influencing macrophage polarization, neutrophils, T cells, natural killer (NK) cells, and addressing factors like inflammation, NLRP3 inflammasome, signaling pathways, oxidative stress, and miRNA multi-target interactions. The anti-AGA properties of THMs, including their active components and prescriptions, were systematically summarized and categorized based on their respective therapeutic targets.

CONCLUSION

phenolic, flavonoid, terpenoid and alkaloid compounds in THMs are considered the key ingredients to improve AGA. THMs and their active ingredients achieve enhanced efficacy through interactions with multiple targets, of which NLRP3 is a main therapeutic target. Nonetheless, given the intricate composition of traditional Chinese medicine (TCM), additional research is required to unravel the underlying mechanisms and molecular targets through which THMs alleviate AGA.

Estimation of adherence to urate-lowering therapy in people living with gout using Australia's Pharmaceutical Benefits Scheme and patient-reported dosing

AIMS

The aim of this study was to estimate adherence to urate-lowering therapy (ULT), predominately allopurinol, from Australia's Pharmaceutical Benefits Scheme (PBS) claims database in association with (1) patient-reported doses and (2) World Health Organization's (WHO) defined daily doses (DDD), namely, allopurinol (400 mg/day) or febuxostat (80 mg/day).

METHODS

Proportion of days covered (PDC) was calculated in 108 Gout App (Gout APP) trial participants with at least two recorded ULT dispensings in an approximately 12-month period before provision of intervention or control apps. Adherence was defined as PDC ≥80%. We measured the correlation between the two methods of calculating PDC using a Wilcoxon signed rank test. Agreement between ULT-taking status (self-reports) and ULT-dispensed status (PBS records) was tested with Cohen's kappa (κ), and positive and negative percent agreement.

RESULTS

Allopurinol was prescribed in 93.5% of participants taking ULT. Their self-reported mean daily dose (SD) was 291 (167) mg/day. Mean PDC (SD) for allopurinol was 83% (21%) calculated using self-reported dose, and 63% (24%) using WHO's DDD. Sixty-three percent of allopurinol users were identified as adherent (PDC ≥80%) using self-reported dose. There was good agreement between self-reported ULT use and PBS dispensing claims (κ = 0.708, P < .001; positive percent agreement = 90%, negative percent agreement = 82%).

CONCLUSIONS

Participant-reported allopurinol daily doses, in addition to PBS dispensing claims, may enhance confidence in estimating PDC and adherence compared to using DDD. This approach improves adherence estimations from pharmaceutical claims datasets for medications where daily doses vary between individuals or where there is a wide therapeutic dose range.

The COMPARE head-to-head, randomized controlled trial of SEL-212 (pegadricase plus rapamycin-containing nanoparticle, ImmTOR™) versus pegloticase for refractory gout

OBJECTIVES

Serum urate (SU) lowering with PEGylated uricases in gout can reduce flares and tophi. However, treatment-emergent anti-drug antibodies adversely affect safety and efficacy and the currently approved PEGylated uricase pegloticase requires twice-monthly infusions. Investigational SEL-212 therapy aims to promote uricase-specific tolerance via monthly sequential infusions of a proprietary rapamycin-containing nanoparticle (ImmTOR) and pegadricase.

METHODS

COMPARE was a randomized, phase 2, open-label trial of SEL-212 vs pegloticase in adults with refractory gout. SEL-212 [ImmTOR (0.15 mg/kg) and pegadricase (0.2 mg/kg)] was infused monthly or pegloticase (8 mg) twice monthly for 6 months. The primary endpoint was the proportion of participants with SU <6 mg/dl for ≥80% of the time during 3 and 6 months. Secondary outcomes were mean SU, gout flares, number of tender and/or swollen joints and safety.

RESULTS

During months 3 and 6 combined, numerically more participants achieved and maintained a SU <6 mg/dl for ≥80% of the time with SEL-212 vs pegloticase (53.0% vs 46.0%, P = 0.181). The percentage reductions in SU levels were statistically greater during months 3 and 6 with SEL-212 vs pegloticase (-73.79% and -47.96%, P = 0.0161). Reductions in gout flare incidence and number of tender and/or swollen joints were comparable between treatments. There were numerical differences between the most common treatment-related adverse events of interest with SEL-212 and pegloticase: gout flares (60.2% vs 50.6%), infections (25.3% vs 18.4%) and infusion-related reactions (15.7% vs 11.5%), respectively. Stomatitis (and related terms) was experienced by eight participants (9.6%) with SEL-212 and none with pegloticase. Stomatitis, a known event for rapamycin, was associated with ImmTOR only.

CONCLUSIONS

SEL-212 efficacy and tolerability were comparable to pegloticase in refractory gout. This was associated with a substantial reduction in treatment burden with SEL-212 due to decreased infusion frequency vs pegloticase.

CLINICAL TRIAL REGISTRATION

NCT03905512.

Effects of different levels of dried onion powder on nutrient digestibility, biochemical parameters, and nitrogen balance in Wistar albino rats with induced hyperuricemia

Introduction: Onions (Allium cepa L.) are excellent sources of bioactive compounds and phytochemicals such as allicin, quercetin, fisetin, and other sulfurous compounds. Therefore, our study aimed to investigate the effects of dried onion powder on growth performance, nitrogen balance, and biochemical parameters in Wistar albino rats with induced hyperuricemia. Methods: A total of 24 rats were randomly divided into four groups, with six in each group: HU (positive control) and HOT1, HOT2, and HOT3 groups, which received a diet containing onion powder at concentrations of 11.13, 14.84, and 18.61 g/100 g, respectively. Hyperuricemia was induced in rats by administering a new formulation intraperitoneally (250 mg/kg potassium oxonate) and orally (40 mg/kg potassium bromate) daily for 14 days. After confirmation of hyperuricemia induction, rats were fed with onion-treated diets with various concentrations of quercetin for 21 days. Results: Significant decreases (p ≤ 0.05) in serum uric acid, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, total bilirubin, total cholesterol, and low-density lipoprotein were observed. An increasing trend (p ≤ 0.05) in the levels of hemoglobin (Hb), white blood cell (WBC), red blood cell (RBC), and platelet count was observed. An improvement in the levels of serum high-density lipoprotein, triglycerides, blood urea nitrogen, serum creatinine, serum total protein and neutrophils, lymphocytes, and monocytes was observed. A positive progress (p ≤ 0.05) was observed in growth performance and nutrient digestibility. Conclusion: In conclusion, a significantly lower uric acid level was observed in rats fed with HOT2 diet. Based on the ratio of the surface area (human/rat), the best recommended dose of onion for the incidence and prevention of hyperuricemia is 189.95 g, corresponding to the dose of 204 mg/day of quercetin in humans.

Mechanisms and rationale for uricase use in patients with gout

Xanthine oxidase inhibitors such as allopurinol and febuxostat have been the mainstay urate-lowering therapy (ULT) for treating hyperuricaemia in patients with gout. However, not all patients receiving oral ULT achieve the target serum urate level, in part because some patients cannot tolerate, or have actual or misconceived contraindications to, their use, mainly due to comorbidities. ULT dosage is also limited by formularies and clinical inertia. This failure to sufficiently lower serum urate levels can lead to difficult-to-treat or uncontrolled gout, usually due to poorly managed and/or under-treated gout. In species other than humans, uricase (urate oxidase) converts urate to allantoin, which is more soluble in urine than uric acid. Exogenic uricases are an exciting therapeutic option for patients with gout. They can be viewed as enzyme replacement therapy. Uricases are being used to treat uncontrolled gout, and can achieve rapid reduction of hyperuricaemia, dramatic resolution of tophi, decreased chronic joint pain and improved quality of life. Availability, cost and uricase immunogenicity have limited their use. Uricases could become a leading choice in severe and difficult-to-treat gout as induction and/or debulking therapy (that is, for lowering of the urate pool) to be followed by chronic oral ULT. This Review summarizes the evidence regarding available uricases and those in the pipeline, their debulking effect and their outcomes related to gout and beyond.

Phase 2 Dose-Finding Study in Patients with Gout Using SEL-212, a Novel PEGylated Uricase (SEL-037) Combined with Tolerogenic Nanoparticles (SEL-110)

INTRODUCTION

SEL-212 is a developmental treatment for uncontrolled gout characterized by serum uric acid (sUA) levels ≥ 6 mg/dl despite treatment. It comprises a novel PEGylated uricase (SEL-037; also called pegadricase) co-administered with tolerogenic nanoparticles containing sirolimus (rapamycin) (SEL-110; also called ImmTOR®), which mitigates the formation of anti-drug antibodies (ADAs) against uricase and SEL-037 (PEGylated uricase), thereby enabling sustained sUA control (sUA < 6 mg/dl). The aim of this study was to identify appropriate dosing for SEL-037 and SEL-110 for use in phase 3 clinical trials.

METHODS

This open-label phase 2 study was conducted in adults with symptomatic gout and sUA ≥ 6 mg/dl. Participants received five monthly infusions of SEL-037 (0.2 or 0.4 mg/kg) alone or in combination with three or five monthly infusions of SEL-110 (0.05-0.15 mg/kg). Safety, tolerability, sUA, ADAs, and tophi were monitored for 6 months.

RESULTS

A total of 152 adults completed the study. SEL-037 alone resulted in rapid sUA reductions that were not sustained beyond 30 days in most participants due to ADA formation and loss of uricase activity. Levels of ADAs decreased with increasing doses of SEL-110 up to 0.1 mg/kg, with anti-uricase titers < 1080 correlating with sustained sUA control and reductions in tophi. Overall, 66% of evaluable participants achieved sUA control at week 20 following five monthly doses of SEL-037 0.2 mg/kg + SEL-110 0.1-0.15 mg/kg, whereas only 26% achieved sUA control at week 20 when SEL-110 was withdrawn after week 12. Compared to other dose combinations, SEL-037 0.2 mg/kg + SEL-110 0.15 mg/kg achieved the greatest sUA control at week 12 and was well-tolerated with no safety concerns.

CONCLUSION

Results provide continued support for the use of multiple monthly administrations of SEL-037 0.2 mg/kg + SEL-110 0.1-0.15 mg/kg in clinical trials for SEL-212.

TRIAL REGISTRATION

ClinicalTrials.gov identifier, NCT02959918.

A multicentre, efficacy and safety study of methotrexate to increase response rates in patients with uncontrolled gout receiving pegloticase (MIRROR): 12-month efficacy, safety, immunogenicity, and pharmacokinetic findings during long-term extension of an open-label study

BACKGROUND

Publications suggest immunomodulation co-therapy improves responder rates in uncontrolled/refractory gout patients undergoing pegloticase treatment. The MIRROR open-label trial showed a 6-month pegloticase + methotrexate co-therapy responder rate of 79%, compared to an established 42% pegloticase monotherapy responder rate. Longer-term efficacy/safety data are presented here.

METHODS

Uncontrolled gout patients (serum urate [SU] ≥ 6 mg/dL and SU ≥ 6 mg/dL despite urate-lowering therapy [ULT], ULT intolerance, or functionally-limiting tophi) were included. Patients with immunocompromised status, G6PD deficiency, severe kidney disease, or methotrexate contraindication were excluded. Oral methotrexate (15 mg/week) and folic acid (1 mg/day) were administered 4 weeks before and during pegloticase therapy. Twelve-month responder rate (SU < 6 mg/dL for ≥ 80% during month 12), 52-week change from baseline in SU, and extended safety were examined. Efficacy analyses were performed for patients receiving ≥ 1 pegloticase infusion. Pharmacokinetics (PK)/anti-drug antibodies (ADAs) were examined and related to efficacy/safety findings.

RESULTS

Fourteen patients were included (all male, 49.3 ± 8.7 years, 13.8 ± 7.4-year gout history, pre-therapy SU 9.2 ± 2.5 mg/dL). Three patients were non-responders and discontinued study treatment before 24 weeks, one patient exited the study per protocol at 24 weeks (enrolled prior to treatment extension amendment), and 10 remained in the study through week 52. Of the 10, 8 completed 52 weeks of pegloticase + methotrexate and were 12-month responders. The remaining two discontinued pegloticase + methotrexate at week 24 (met treatment goals) and stayed in the study under observation (allopurinol prescribed at physicians' discretion); one remained a responder at 12 months. At 52 weeks, change from baseline in SU was - 8.2 ± 4.1 mg/dL (SU 1.1 ± 2.4 mg/dL, n = 10). Gout flares were common early in treatment but progressively decreased while on therapy (weeks 1-12, 13/14 [92.9%]; weeks 36-52, 2/8 [25.0%]). One patient recovered from sepsis (serious AE). Two non-responders developed high ADA titers; fewer patients had trough concentrations (Cmin) below the quantitation limit (BQL), and the median Cmin was higher (1.03 µg/mL vs. BQL) than pegloticase monotherapy trials.

CONCLUSIONS

Pegloticase + methotrexate co-therapy was well-tolerated over 12 months, with sustained SU lowering, progressive gout flare reduction, and no new safety concerns. Antibody/PK findings suggest methotrexate attenuates ADA formation, coincident with higher treatment response rates.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT03635957 . Registered on 17 August 2018.

Evaluation of the anti-gout effect of Sonchus Arvensis on monosodium urate crystal-induced gout arthritis via anti-inflammatory action - an in vivo study

Background and aims

Sonchus arvensis is an Indonesian plant with strong therapeutic effects. Various studies have shown that this plant is useful in treating kidney stone disorders, and recent studies have shown that S. arvensis extract can reduce inflammation caused by monosodium urate crystal deposition in the synovial tissue. This study was aimed to explore the extract of Sonchus arvensis, via fractionation, to optimize the specific content of S. arvensis with anti-inflammatory potential in gout arthritis.

Methods

The study included 30 rats (Rattus norvegicus) Wistar strain obtained from the Eureka Research Laboratory (Palembang, Indonesia) weighing between 200 - 250 grams. After one week of acclimatization, the rats were randomly divided into six groups, each group containing five animals; normal control group, monosodium urate group (negative control), colchicine group, hexane fraction of S. arvensis group, ethyl-acetate fraction of S. arvensis group and water fraction group. Before monosodium urate administration, rats in the colchicine group, as a positive control group, were given orally for seven days with 0.28 mg/kg/day colchicine. IL-1β levels in joint synovial fluid were examined with Rat ELISA interleukin-1β.

Results

S. arvensis water fraction showed the most significant reduction in inflammatory cells compared to the hexane or ethyl acetate fractions. The water fraction of S. arvensis group had an equal effect with positive control in reducing the infiltration of inflammatory cells in the synovial tissue.

Conclusion

Sonchus arvensis water fraction has anti-gout effects in monosodium urate-induced gout arthritis in rats by decreasing the inflammatory response in the synovial joint.

Rheumatologists' understanding of refractory gout: a questionnaire survey in China

Objective

To explore the understanding of refractory gout in Chinese rheumatologists.

Methods

We conducted an anonymous survey of rheumatologists attending an annual national academic conference on rheumatism.

Results

Of the 910 rheumatologists who completed the questionnaire, 751 (82.5%) had received relevant continuing medical education (CME). Of these, 140 (18.6%) rheumatologists did not select xanthine oxidase inhibitors as the first treatment for patients with chronic tophaceous gout. Of all respondents, 113 (12.4%), 251 (27.6%) and 324 (35.6%) prescribed incorrect maximum doses of allopurinol, febuxostat and benzbromarone, respectively; this tendency was more pronounced in the non-CME group. Most rheumatologists agreed that complications and comorbidities increased the difficulty of gout management and considered the term refractory gout to describe those cases with uncontrolled symptoms, unmet treatment targets or non-shrinkage of tophi after standardized drug treatment. Moreover, 62.8% (472/751) of specialists considered that a diagnosis of refractory gout was appropriate for patients whose lifestyle and compliance failed to improve despite adequate education and regular urate-lowering therapy.

Conclusions

Incorrect and inadequate drug therapy may contribute to some cases of refractory gout, especially in physicians without CME. An emphasis on non-drug therapy and the management of comorbidities and complications may reduce cases of refractory gout.

Pegloticase in Combination With Methotrexate in Patients With Uncontrolled Gout: A Multicenter, Open-label Study (MIRROR)

OBJECTIVE

To examine the efficacy and safety of pegloticase in combination with methotrexate (MTX) in patients with uncontrolled gout in an exploratory, open-label clinical trial (ClinicalTrials.gov: NCT03635957) prior to a randomized, controlled trial.

METHODS

A multicenter, open-label efficacy and safety study of pegloticase with MTX co-treatment was conducted in patients with uncontrolled gout. Patients were administered oral MTX (15 mg/week) and folic acid (1 mg/day) 4 weeks prior to and throughout pegloticase treatment. The primary study outcome was the proportion of responders, defined as serum uric acid (sUA) < 6 mg/dL for ≥ 80% of the time during Month 6 (Weeks 20, 22, and 24). All analyses were performed on a modified intent-to-treat population, defined as patients who received ≥ 1 pegloticase infusion.

RESULTS

Seventeen patients were screened and 14 patients (all men, average age 49.3 ± 8.7 years) were enrolled. On Day 1, mean sUA was 9.2 ± 2.5 mg/dL, and 12 of the 14 patients had visible tophi. At the 6-month timepoint, 11/14 (78.6%, 95% CI 49.2-95.3%) met the responder definition, with 3 patients discontinuing after meeting protocol-defined treatment discontinuation rules (preinfusion sUA values > 6 mg/dL at 2 consecutive scheduled visits). All patients tolerated MTX. No new safety concerns were identified.

CONCLUSION

In this study, an increased proportion of patients maintained therapeutic response at 6 months when treated concomitantly with MTX and pegloticase as compared to the previously reported 42% using pegloticase alone. These results support the need for a randomized study of MTX or placebo with pegloticase to validate these open-label findings.

Increased Efficacy and Tolerability of Pegloticase in Patients With Uncontrolled Gout Co-Treated With Methotrexate: A Retrospective Study

INTRODUCTION

Gout is a painful inflammatory condition caused by chronically elevated serum uric acid levels (sUA). When standard urate-lowering therapies fail/are not tolerated, uncontrolled gout (elevated sUA, subcutaneous tophi, chronic gouty arthritis, frequent flares) can occur. Pegloticase, a recombinant uricase, converts uric acid to allantoin, a readily excreted molecule. Responder rate in trials was 42%, limited by anti-drug antibody (ADA) development. Immunomodulators attenuate ADA formation and case reports suggest immunomodulation increases pegloticase responder rates. The current study retrospectively examined responder rate in patients undergoing methotrexate/pegloticase co-therapy.

METHODS

Patients who underwent methotrexate/pegloticase co-treatment at a single rheumatology practice were included. Demographics, clinical, treatment, and safety parameters were collected. The primary outcome was the proportion of responders (≥ 12 biweekly pegloticase infusions, sUA < 6 mg/dl just prior to infusion 12).

RESULTS

Ten patients (nine men, 52.3 ± 13.5 years) with uncontrolled tophaceous gout (erosive damage, ulcerative tophi, frequent flares, gout-related hospitalizations) were included. Patients had failed allopurinol (100-300 mg) or febuxostat (40 mg) therapy (doses not increased because of intolerance, kidney concerns, noncompliance, or rapid tophi resolution requirement). Baseline sUA was 9.42 ± 2.05 mg/dl. Along with standard pre-infusion prophylaxis, nine patients received subcutaneous methotrexate (25 mg/week) initiated 14-35 days before pegloticase and one patient received oral methotrexate (12.5 mg/week) initiated 14 days after pegloticase. Eight patients (80%) were responders, receiving 15.5 ± 3.8 infusions (range, 12-21) over 31.8 ± 9.5 weeks. One patient had efficacy loss with mild infusion reaction during infusion 4 and one patient was lost to follow-up after infusion 5. One patient reported one gout flare. No new safety concerns emerged.

CONCLUSIONS

Methotrexate/pegloticase co-therapy resulted in a higher responder rate than the established 42% with pegloticase alone. Therefore, methotrexate/pegloticase co-therapy may safely allow more patients to benefit from a full treatment course, likely through ADA attenuation.

Refractory gout - does it exist?

Refractory gout (RG) has been increasingly recognized to be a major problem in clinical care. Patients diagnosed with RG have been assumed to be non-adherent, or under-dosed, to the greater part. In a minority, pathophysiological mechanisms have been discussed. During the last two decades, however, none of the studies differentiated non-adherence from impaired response to drug treatment. A definition of adherence has been proposed in the case of allopurinol treatment (oxipurinol in serum, >20 µmol/l), which would seem to confirm a dose of about 50 mg/d being taken by the patients. Guidelines for treating gout published by national or international rheumatology societies do provide very little, if any, information on how to evaluate patients with RG. Coinciding with the development of the xanthine oxidase inhibitor, febuxostat, a moderate increase in the number of publications on RG was observed, with a sharp rise following after its approval for clinical use. It was demonstrated recently that intensive training and supervision of patients with gout resulted in very low numbers of patients not reaching treatment targets. It should be remembered that allopurinol, is an ideal instrument for differentiating non-adherence from true impaired response. We conclude that, apart from very rare patients, needing confirmation of such a diagnosis by metabolic ward studies, RG does not exist, and with close to hundred percent, treatment failure is due to patient and physician behavior.

The Minimal Effect of Linker Length for Fatty Acid Conjugation to a Small Protein on the Serum Half-Life Extension

Conjugation of serum albumin or one of its ligands (such as fatty acid) has been an effective strategy to prolong the serum half-lives of drugs via neonatal Fc receptor (FcRn)–mediated recycling of albumin. So far, fatty acid (FA) has been effective in prolonging the serum half-lives for therapeutic peptides and small proteins, but not for large therapeutic proteins. Very recently, it was reported a large protein conjugated to FA competes with the binding of FcRn with serum albumin, leading to limited serum half-life extension, because primary FA binding sites in serum albumin partially overlap with FcRn binding sites. In order to prevent such competition, longer linkers between FA and the large proteins were required. Herein, we hypothesized that small proteins do not cause substantial competition for FcRn binding to albumin, resulting in the extended serum half-life. Using a small protein (28 kDa), we investigated whether the intramolecular distance in FA-protein conjugate affects the FcRn binding with albumin and serum half-life using linkers with varying lengths. Unlike with the FA-conjugated large protein, all FA-conjugated small proteins with different linkers exhibited comparable the FcRn binding to albumin and extended serum half-life.

CD44 Receptor Mediates Urate Crystal Phagocytosis by Macrophages and Regulates Inflammation in A Murine Peritoneal Model of Acute Gout

Gout is a chronic arthritis caused by the deposition of poorly soluble monosodium urate monohydrate (MSU) crystals in peripheral joints. Resident macrophages initiate inflammation in response to MSU mediated by NF-κB nuclear translocation and NLRP3 inflammasome activation. We investigated the role of CD44, a transmembrane receptor, in mediating MSU phagocytosis by macrophages. We used an antibody that sheds the extracellular domain (ECD) of CD44 to study the role of the receptor and its associated protein phosphatase 2A (PP2A) in macrophage activation. We also studied the significance of CD44 in mediating MSU inflammation in-vivo. Cd44^−/− BMDMs showed reduced MSU phagocytosis, LDH release, IL-1β expression and production compared to Cd44^+/+ BMDMs. Elevated CD44 staining was detected intracellularly and CD44 colocalized with α-tubulin as a result of MSU exposure and ECD-shedding reduced MSU phagocytosis in murine and human macrophages. Anti-CD44 antibody treatment reduced NF-κB p65 subunit nuclear levels, IL-1β expression, pro-IL-1β and IL-8 production in MSU stimulated THP-1 macrophages (p < 0.01). The effect of the antibody was mediated by an enhancement in PP2A activity. CD44 ECD-shedding reduced the conversion of procaspase-1 to active caspase-1, caspase-1 activity and resultant generation of mature IL-1β in macrophages. Neutrophil and monocyte influx and upregulated production of IL-1β was evident in wildtype mice. MSU failed to trigger neutrophil and monocyte recruitment in Cd44^−/− mice and lower IL-1β levels were detected in peritoneal lavages from Cd44^−/− mice (p < 0.01). Anti-CD44 antibody treatment reduced neutrophil and monocyte recruitment and resulted in reduced lavage IL-1β levels in the same model. CD44 plays a biologically significant role in mediating phagocytosis of MSU and downstream inflammation and is a novel target in gout treatment.

Production and Characterization of Recombinant Wild Type Uricase from Indonesian Coelacanth (L. menadoensis) and Improvement of Its Thermostability by In Silico Rational Design and Disulphide Bridges Engineering

The ideal therapeutic uricase (UOX) is expected to have the following properties; high expression level, high activity, high thermostability, high solubility and low immunogenicity. The latter property is believed to depend largely on sequence identity to the deduced human UOX (dH-UOX). Herein, we explored L. menadoensis uricase (LM-UOX) and found that it has 65% sequence identity to dH-UOX, 68% to the therapeutic chimeric porcine-baboon UOX (PBC) and 70% to the resurrected ancient mammal UOX. To study its biochemical properties, recombinant LM-UOX was produced in E. coli and purified to more than 95% homogeneity. The enzyme had specific activity up to 10.45 unit/mg, which was about 2-fold higher than that of the PBC. One-litre culture yielded purified protein up to 132 mg. Based on homology modelling, we successfully engineered I27C/N289C mutant, which was proven to contain inter-subunit disulphide bridges. The mutant had similar specific activity and production yield to that of wild type (WT) but its thermostability was dramatically improved. Up on storage at −20 °C and 4 °C, the mutant retained ~100% activity for at least 60 days. By keeping at 37 °C, the mutant retained ~100% activity for 15 days, which was 120-fold longer than that of the wild type. Thus, the I27C/N289C mutant has potential to be developed for treatment of hyperuricemia.

NLRP3 inflammasome inhibitor OLT1177 suppresses joint inflammation in murine models of acute arthritis

BACKGROUND

Activation of the NLRP3 inflammasome in gout amplifies the inflammatory response and mediates further damage. In the current study, we assessed the therapeutic effect of OLT1177, an orally active NLRP3 inflammasome inhibitor that is safe in humans, in murine acute arthritis models.

METHODS

Zymosan or monosodium urate (MSU) crystals were injected intra-articularly (i.a.) into mouse knee joints to induce reactive or gouty arthritis. Joint swelling, articular cell infiltration, and synovial cytokines were evaluated 25 hours and 4 hours following zymosan or MSU challenge, respectively. OLT1177 was administrated intraperitoneally by oral gavage or in the food by an OLT1177-enriched diet.

RESULTS

OLT1177 reduced zymosan-induced joint swelling (p < 0.001), cell influx (p < 0.01), and synovial levels of interleukin (IL)-1β, IL-6, and chemokine (C-X-C motif) ligand 1 (CXCL1) (p < 0.05), respectively, when compared with vehicle-treated mice. Plasma OLT1177 levels correlated (p < 0.001) dose-dependently with reduction in joint inflammation. Treatment of mice with OLT1177 limited MSU crystal articular inflammation (p > 0.0001), which was associated with decreased synovial IL-1β, IL-6, myeloperoxidase, and CXCL1 levels (p < 0.01) compared with vehicle-treated mice. When administrated orally 1 hour after MSU challenge, OLT1177 reduced joint inflammation, processing of IL-1β, and synovial phosphorylated c-Jun N-terminal kinase compared with the vehicle group. Mice were fed an OLT1177-enriched diet for 3 weeks and then challenged i.a. with MSU crystals. Joint swelling, synovial IL-1β, and expression of Nlrp3 and Il1b were significantly reduced in synovial tissues in mice fed an OLT1177-enriched diet when compared with the standard diet group.

CONCLUSIONS

Oral OLT1177 is highly effective in ameliorating reactive as well as gouty arthritis.

Hypouricemic Effect of Ethanol Extract of Aster glehni Leaves in Potassium Oxonate-Induced Hyperuricemic Rats

The prevalence of gout is increasing worldwide, and control of serum uric acid level has been regarded as one of the therapeutic methods for gout. Inhibition of xanthine oxidase (XO) activity which can oxidize hypoxanthine to uric acid has been commonly proposed to decrease serum uric acid level. The aim of this study was to demonstrate the hypouricemic effect of ethanol extract of Aster glehni leaves (EAG) by in vitro and in vivo study in potassium oxonate (PO)-induced hyperuricemic rats. EAG possessed 132.5 ± 6.8 mg QE/g of total flavonoid and showed antioxidant activity. EAG showed in vitro and in vivo inhibitory activity against XO and significantly decreased serum uric acid level in PO-induced hyperuricemic rats without liver toxicity. These results show that EAG significantly attenuates hyperuricemia by inhibiting XO activity, which resulted in the decrease of serum uric acid level. Therefore, EAG might possess a potential therapeutic ability for improving gout.

'Shi Han Quan' natural soda water prevents development of gout

PURPOSE

This study aimed to explore the regulatory mechanism of the natural soda Shi Han Quan (SHQ) in the development of gout.

METHODS

Human umbilical vein endothelial cells (HUVECs) were stimulated with monosodium urate (MSU) for 24 h to induce acute gouty inflammation in vitro. HUVECs were divided into four groups: ddH₂ O group, ddH₂ O + MSU group, 1/2 ddH₂ O +1/2 SHQ + MSU group, and SHQ + MSU group. The effects of SHQ on cell viability, concentration and expression of intercellular adhesion molecule-1 (ICAM-1), and MSU-induced release of interleukin (IL)-1β and IL-6 were investigated. Additionally, cell viability and ICAM-1 concentration and expression were detected after HUVECs were incubated with the culture supernatant of THP-1 cells that had been treated with phorbol 12-myristate 13-acetate (PMA), MSU and SHQ for 24 h.

RESULTS

The viability of HUVECs was significantly decreased with increasing transfection concentrations of MSU, and MSU treatment resulted in a significant increase of the concentration and expression of ICAM-1. In addition, SHQ improved the MSU-induced decrease in cell viability and alleviated MSU-mediated increase in ICAM-1 levels. Moreover, SHQ decreased MSU-induced release of IL-1β and IL-6. After HUVECs were incubated with the culture supernatant of THP-1 cells that had been treated with PMA, MSU and SHQ for 24 h, SHQ also markedly alleviated the effects of MSU, such as by increasing cell viability and decreasing ICAM-1 levels.

CONCLUSIONS

Drinking natural soda water may have a significant role in preventing gouty inflammation.

The tyrosine kinase inhibitor imatinib mesylate suppresses uric acid crystal-induced acute gouty arthritis in mice

Gouty arthritis is caused by the deposition of monosodium urate (MSU) crystals in joints. Despite many treatment options for gout, there is a substantial need for alternative treatments for patients unresponsive to current therapies. Tyrosine kinase inhibitors have demonstrated therapeutic benefit in experimental models of antibody-dependent arthritis and in rheumatoid arthritis in humans, but to date, the potential effects of such inhibitors on gouty arthritis has not been evaluated. Here we demonstrate that treatment with the tyrosine kinase inhibitor imatinib mesylate (imatinib) can suppress inflammation induced by injection of MSU crystals into subcutaneous air pouches or into the ankle joint of wild type mice. Moreover, imatinib treatment also largely abolished the lower levels of inflammation which developed in IL-1R1-/- or KitW-sh/W-sh mice, indicating that this drug can inhibit IL-1-independent pathways, as well as mast cell-independent pathways, contributing to pathology in this model. Imatinib treatment not only prevented ankle swelling and synovial inflammation when administered before MSU crystals but also diminished these features when administrated after the injection of MSU crystals, a therapeutic protocol more closely mimicking the clinical situation in which treatment occurs after the development of an acute gout flare. Finally, we also assessed the efficiency of local intra-articular injections of imatinib-loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticles in this model of acute gout. Treatment with low doses of this long-acting imatinib:PLGA formulation was able to reduce ankle swelling in a therapeutic protocol. Altogether, these results raise the possibility that tyrosine kinase inhibitors might have utility in the treatment of acute gout in humans.

Pegloticase in gout treatment - safety issues, latest evidence and clinical considerations

Gout is a common rheumatic condition, with increasing prevalence in recent decades. The mainstay of treatment for gout is oral urate-lowering therapy (ULT), typically with xanthine oxidase inhibitors (XOIs). Unfortunately, a proportion of patients have persistent gout that is refractory to ULT. Pegloticase, a recombinant pegylated uricase, has been approved by the US Food and Drug Administration for the treatment of refractory gout. However, concern has been raised regarding the risk of infusion reactions, which are now understood to be largely due to the development of antipegloticase antibodies. Discontinuation of pegloticase upon failure to lower serum urate has been shown to markedly reduce infusion reaction risk, but deprives patients of what, in many cases, is a last-resort treatment. In this manuscript, we review the rationale, mechanism of action, efficacy and safety of pegloticase. Additionally, we focus on potential strategies to reduce pegloticase immunogenicity and potentially make this important agent available to a wider group of patients requiring treatment.

In Vitro and In Vivo Studies on Quercus acuta Thunb. (Fagaceae) Extract: Active Constituents, Serum Uric Acid Suppression, and Xanthine Oxidase Inhibitory Activity

Quercus acuta Thunb. (Fagaceae) (QA) is cultivated as a dietary and ornamental plant in China, Japan, South Korea, and Taiwan. It has been widely used as the main ingredient of acorn tofu, a traditional food in China and South Korea. The aim of this study was to determine in vitro and in vivo xanthine oxidase (XO) inhibitory and antihyperuricemic activities of an ethyl acetate extract of QA leaf (QALE) and identify its active phytochemicals using gas chromatography-mass spectrometry (GC-MS) and liquid chromatography (LC) systems. The QALE was found to possess potent in vitro antioxidant and XO inhibitory activities. In vivo study using hyperuricemic mice induced with potassium oxonate demonstrated that the QALE could inhibit hepatic XO activity at a relatively low oral dose (50 mg/kg) and significantly alleviate hyperuricemia to a similar extent as allopurinol. Several active compounds including vitamin E known to possess XO inhibitory activity were identified from the QALE. To the best of our knowledge, this is the first study that reports the active constituents and antihyperuricemic effect of QA, suggesting that it is feasible to use QALE as a food therapy or alternative medicine for alleviating hyperuricemia and gout.

A world of hurt: failure to achieve treatment goals in patients with gout requires a paradigm shift

BACKGROUND

Gout continues to be underdiagnosed and poorly managed despite the potential for cure. US and European management guidelines recommend treating to target serum urate (sUA) levels of <6 mg/dL (or <5 mg/dL to durably improve severe symptoms), with use of regular sUA monitoring, but studies suggest relatively poor adherence to these recommendations. This study investigates the real-world state of gout management in the United States by describing the characteristics of a large patient population treated in primary care and rheumatology settings.

METHODS

A retrospective chart audit, conducted among 124 primary care physicians and 125 rheumatologists, included 1245 patients with gout. Physicians completed structured case report forms capturing 12 months of sUA laboratory values, flare counts, comorbidities, types and doses of treatment, treatment duration, diagnosis date, physician specialty and socio-demographic factors. Focusing on the xanthine oxidase inhibitors (n = 858), descriptive statistics and multivariate models characterized relationships between patient characteristics, disease control, and treatment.

RESULTS

Only 83 (11%) patients achieved disease control, defined as a 12-month average sUA ≤6 mg/dL, no flares, and no tophi. Patients with greatest disease severity (defined as sUA >6 mg/dL, ≥2 flares per year, and tophi) were more likely to have kidney disease and other comorbidities. In a multivariate model, predictors of more severe gout were rheumatologist (vs primary care) management, febuxostat (vs allopurinol) use and presence of comorbid conditions.

CONCLUSION

Our findings confirm the inadequacy of gout management in the real-world setting. Regular monitoring, including sUA measurement as recommended in guidelines, is important to assess gout control. Our analyses also demonstrate that patients with more severe gout are more likely to have comorbid conditions, be treated by a specialist and use newer therapies.

Comparative effectiveness of urate lowering with febuxostat versus allopurinol in gout: analyses from large U.S. managed care cohort

Introduction

To assess the comparative effectiveness of febuxostat and allopurinol in reducing serum urate (sUA) levels in a real-world U.S. managed care setting.

Methods

This retrospective study utilized 2009 to 2012 medical and pharmacy claims and laboratory data from a large U.S. commercial and Medicare Advantage health plan. Study patients had at least one medical claim with a diagnosis of gout, at least one filled prescription for febuxostat or allopurinol and at least one sUA measurement post-index prescription. Reduction in sUA was examined using propensity score-matched cohorts, matched on patient demographics (gender, age), baseline sUA, comorbidities, geographic region and insurance type.

Results

The study sample included 2,015 patients taking febuxostat and 14,025 taking allopurinol. At baseline, febuxostat users had a higher Quan-Charlson comorbidity score (0.78 vs. 0.53; P <0.001), but similar age and gender distribution. Mean (standard deviation (SD)) sUA level following propensity score matching among treatment-naïve febuxostat vs. allopurinol users (n = 873 each) were: pre-index sUA, 8.86 (SD, 1.79) vs. 8.72 (SD, 1.63; P = 0.20); and post-index sUA, 6.53 (SD, 2.01) vs. 6.71 (SD, 1.70; P = 0.04), respectively. A higher proportion of febuxostat users attained sUA goals of <6.0 mg/dl (56.9% vs. 44.8%; P <0.001) and <5.0 mg/dl (35.5% vs. 19.2%; P <0.001), respectively. Time to achieve sUA goals of <6.0 mg/dl (346 vs. 397 days; P <0.001) and <5.0 mg/dl was shorter in febuxostat vs. allopurinol users (431 vs. 478 days; P <0.001), respectively. Similar observations were made for overall propensity score-matched cohorts that included both treatment-naïve and current users (n = 1,932 each).

Conclusions

Febuxostat was more effective than allopurinol at the currently used doses (40 mg/day for febuxostat in 83% users and 300 mg/day or lower for allopurinol in 97% users) in lowering sUA in gout patients as demonstrated by post-index mean sUA level, the likelihood of and the time to achieving sUA goals.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-015-0624-3) contains supplementary material, which is available to authorized users.

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

BACKGROUND

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

FINDINGS

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

CONCLUSIONS

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

TRIAL REGISTRATION

Clinical trial identifier: NCT00325195.

How to manage patients with gout

OBJECTIVES

Recently, after almost 50 years of dormancy, new therapeutic agents for the management of gout have entered the market or are in clinical development. In this article, the current guidelines for the diagnosis and management of gout are reviewed.

METHODS

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

RESULTS AND CONCLUSIONS

Although our therapeutic arsenal is strong, and effective gout management with urate lowering therapy improves many patient-reported outcomes in clinical trials, major gaps exist in patient understanding of disease and adherence to long-term therapy. Research is required to identify the optimal models of care for patients with gout. However, quality of care in gout can be enhanced through better gout-centered education. To properly manage gout, education of the gout patient is critical, since only the patient who understands their gout will stay with their medication long-term.

Refractory gout attack

Refractory gout attack is an uncommon problem, since gout flares are usually self-limited. This clinical condition is characterized by serum uric acid higher than 6 mg/Dl or continuous manifestations of recurrent flares, chronic arthritis, and increased tophi. We report in this paper a 69-year-old man with a polyarticular and protracted gout attack, despite usual treatment and low urate sera levels. In order to manage this problem, we reviewed gout pathophysiology and developed a therapeutic solution based on benzbromarone pharmacokinetics. We also review herein new options for gout treatment that could be used in similar cases.

The rheumatology of gout

Gout is a metabolic disorder of purine metabolism with primary manifestations of acute and chronic arthritis and tophus formation. The prevalence of gout appears to be increasing and may affect up to 8 million people in the United States. The development of novel therapies for gout after a 40-year hiatus has opened new understanding of this disease. In addition to causing severe musculoskeletal pain, gout is associated with impaired quality of life, reduced functional status, and injury to joints. The quality of care for many patients with gout is unfortunately not in keeping with current guidelines. The approval of new therapies to treat hyperuricemia, such as febuxostat and pegloticase, has increased our knowledge of the challenges of adequately controlling the disease. Rather than providing a comprehensive overview of gout, this review focuses on new developments in the clinical aspects of gout and highlights advances in the drug therapy of gout.

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

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

Effects of orange juice and hesperetin on serum paraoxonase activity and lipid profile in hyperuricemic rats

INTRODUCTION

Hypouricemic, antioxidant and xanthine oxidase inhibitory effects of orange juice and hesperetin have been already indicated. The objective of this study was to investigate the effects of orange juice and hesperetin on paraoxonase and arylesterase activity and lipid profile of hyperuricemic rats.

METHODS

Forty eight male Wistar rats were divided into 8 equal groups of healthy control, healthy+orange juice, healthy+hesperetin, healthy+allopurinol, hyperuricemic control, hyperuricemic+orange juice, hyperurice-mic+hesperetin and hyperuricemic+allopurinol. Hyperuricemia was induced using potassi-um oxonate (250 mg/kg ip). The treatments were carried out by daily gavage of 5 ml/kg orange juice, 5 mg/kg hesperetin and 5 mg/kg allopurinol for 2 weeks. Paraoxonase activi-ty in serum was measured spectrophotometrically using paraoxon and phenylacetate as substrates. Serum lipids levels were determined using enzymatic colorimetric methods.

RESULTS

Hyperuricemia-induced reduction of paraoxonase and arylesterase activity was restored after treatment with orange juice and hesperetin (p<0.05). The effect of both treatments on lipid profile was marginal and only orange juice could significantly increase the levels of HDL-C.

CONCLUSION

Supplementation of orange juice and hesperetin could restore paraoxonase and arylesterase activity in hyperuricemic rats. Orange juice could also partially improve the lipid profile. These effects could have major implications with respect to the prevention of cardiovascular disease in hyperuricemic patients. However, more studies are needed in future investigations.

Uricases as therapeutic agents to treat refractory gout: Current states and future directions

Treatment of refractory gout remains a challenge on drug development. While pegloticase, a recombinant mammalian uricase modified with monomethoxyl-poly(ethylene glycol) (mPEG) is effective in treating refractory gout, after continued treatment for three months biweekly at a therapeutic dose of 0.14 mg/kg body weight, it elicits an immune response against mPEG in nearly 20% of patients. For continued treatment of refractory gout PEGylated uricases at monthly therapeutic doses below 4 μg/kg body weight have promise. To formulate uricases to achieve monthly therapeutic regimens requires pharmacodynamics simulation and experimentation including: (a) molecular engineering of uricases based on rational design and evolution biotechnology in combination to improve their inherent catalytic efficiency, thermostability and selectivity for urate over xanthine and; (b) optimization of the number and distribution of accessible reactive amino acid residues in native uricases for site-specific PEGylation with PEG derivatives with lower of immunogenicity than mPEG to retain activity, minimize immunogenicity and enhance the pharmacokinetics of the PEGylated uricase. These issues are briefly reviewed as a means to stimulate the development of safer uricase formulations for continued treatment of refractory gout.

Gout treatment and comorbidities: a retrospective cohort study in a large US managed care population

Background

Gout prevalence increased in recent years to become one of the most common causes of inflammatory arthritis in most industrialised countries. Comorbidities may affect the disease severity and treatment patterns. We describe the main characteristics of gout patients, gout-related treatment patterns and prevalent comorbidities in a managed care population.

Methods

From the large US PharMetrics Patient-Centric Database, patients aged 20-89 with at least 2 claims for a diagnosis of gout (ICD9 274.xx) and related prescriptions between January 1, 1996 and December 31, 2008 were included. Gout flares were ascertained during follow-up. Sex-specific multivariable Poisson regression models were used to assess factors associated with number of flares.

Results

177,637 gout patients were included (mean age 55.2 years; men 75.6%). Overall, more than half (58.1%) had any of the considered comorbidities; hypertension (36.1%), dyslipidemia (27.0%) and diabetes (15.1%) being the most common. Nonselective NSAIDs were the most commonly dispensed (in 38.7% of patients). Notably, 39% of patients did not receive any prescription medication for gout. Patients with comorbidities were significantly more likely to receive anti-gout prescriptions. During an acute episode the prescription of NSAIDs and colchicine increased; and 29.9% of patients received allopurinol. The risk of flares was associated with cardiometabolic comorbidities and older age in women (highest at age 60-69), while in men it decreased by age. Women with these conditions were 60% more likely to have flares (incidence rate ratio, IRR 1.60;1.48-1.74), while men were 10% (IRR 1.10; 1.06-1.13) more likely.

Conclusions

Comorbidities affected gout treatment patterns and the occurrence and frequency of acute attacks. Cardiometabolic comorbidities, common in this patients' population, were associated with an increased risk of flares.

Pegloticase

Each month, subscribers to The Formulary Monograph Service receive 5 to 6 well-documented monographs on drugs that are newly released or are in late phase 3 trials. The monographs are targeted to Pharmacy & Therapeutics Committees. Subscribers also receive monthly 1-page summary monographs on agents that are useful for agendas and pharmacy/nursing in-services. A comprehensive target drug utilization evaluation/medication use evaluation (DUE/MUE) is also provided each month. With a subscription, the monographs are sent in print and are also available on-line. Monographs can be customized to meet the needs of a facility. Subscribers to The Formulary Monograph Service also receive access to a pharmacy bulletin board, The Formulary Information Exchange (The F.I.X.). All topics pertinent to clinical and hospital pharmacy are discussed on The F.I.X.

Through the cooperation of The Formulary, Hospital Pharmacy publishes selected reviews in this column. For more information about The Formulary Monograph Service or The F.I.X., call The Formulary at 800-322-4349. The January 2011 monograph topics are on dabigatran etexilate mesylate, ceftaroline fosamil, lurasidone hydrochloride tablets, acetaminophen intravenous, and dextromethorphan/quinidine sulfate. The DUE/MUE is on ceftaroline fosamil.

Chronic gout: epidemiology, disease progression, treatment and disease burden

BACKGROUND

Gout is a painful and disabling inflammatory arthritis of increasing prevalence associated with hyperuricemia and the deposition of monosodium urate crystals in soft tissues and joints. Diagnosed gout cases have been estimated at 2.13% of the 2009 US population. The highest incidence occurs in the 65+ year age group, with males more than twice as likely to be afflicted as females.

OBJECTIVE

To present the epidemiology of chronic gout and to discuss its disease burden.

METHODS

This commentary is based on expert opinion and supplemented with published/presented information identified through PubMed and rheumatology associations.

RESULTS

The steady rise of diagnosed gout cases can generally be linked to an aging population with multiple comorbidities, the use of certain prescription medications, and changes in diet and lifestyle. Progression to chronic gout has numerous causes such as poor compliance with, ineffectiveness of, or inability to tolerate prescribed regimens. Despite the availability of urate-lowering therapies (ULT), patients may either have contraindications to them or may not adequately respond. Patients with high flare frequency, tophi, and the inability to maintain serum urate levels below 6 mg/dL with ULT can be categorized as having chronic gout that is refractory, with a substantial disease burden. Based on lack of therapeutic options for urate-lowering for patients with chronic gout refractory to conventional therapy, the economic burden of this small but substantial population contributes disproportionately to the overall economic burden of chronic gout. Recent availability of gout-specific ICD-9-CM codes capturing the cost intense and impactful aspects of the disease - flares and tophi - is likely contribute to understanding the full health economic burden in gout.

CONCLUSION

The impact of chronic gout, especially if refractory to treatment, on functionality, productivity, quality of life and health care costs can be substantial and is deserving of future research.

Anakinra's efficacy is variable in refractory gout: report of ten cases

OBJECTIVES

To evaluate the efficacy of anakinra for patients with acute gout.

METHODS

We reviewed the charts of 10 patients who received anakinra for urate crystal-induced arthritis at the Hospital for Special Surgery since 2007. Demographic information, comorbidities, short-term treatment outcomes, and subsequent flares were reviewed.

RESULTS

Patients in our study had a high prevalence of comorbidities. All patients received corticosteroids before anakinra treatment. The mean number of anakinra injections was 3.2 per patient (100 mg subcutaneously per day). Six patients had a good response. Three patients had a partial response and 1 patient had no response. Nine patients had documented recurrent flares after discontinuing anakinra (ranging from 3 to 45 days after).

CONCLUSION

Anakinra is a therapeutic option for patients with acute urate crystal-induced arthritis who do not respond to or have a contraindication to traditional treatments. Although a short course of anakinra resulted in favorable outcomes for some of our patients, response rates were poorer in our study than in previously published reports, and relapses were common.