Is colchicine prophylaxis required with start-low go-slow allopurinol dose escalation in gout? A non-inferiority randomised double-blind placebo-controlled trial

Analysis of Gout Remission Definitions in a Randomized Controlled Trial of Colchicine Prophylaxis for People With Gout Initiating Allopurinol

OBJECTIVE

To investigate (1) the effect of colchicine prophylaxis on gout remission when commencing urate-lowering therapy (ULT), and (2) illness perceptions of people in remission using 2 definitions of gout remission.

METHODS

Data from a 12-month double-blind placebo-controlled trial of 200 people with gout commencing allopurinol were analyzed. Participants were randomly assigned to prophylaxis with 0.5 mg daily colchicine or placebo for 6 months, followed by 6 months of additional follow-up. Gout remission was assessed using the 2016 preliminary definition or simplified definition without patient-reported outcomes. Illness perceptions were assessed using a gout-specific version of the Brief Illness Perception Questionnaire.

RESULTS

In the first 6 months, few participants were in remission according to either the 2016 preliminary definition (3% for colchicine and 4% for placebo) or the simplified definition (7% for colchicine and 12% for placebo). In the second 6 months, after study drug (colchicine or placebo) discontinuation, fewer participants in the colchicine group than in the placebo group were in remission according to the 2016 preliminary definition (4% vs 14%, P = 0.03), and the simplified definition (14% vs 28%, P = 0.02). Participants fulfilling remission using either definition had more favorable perceptions about their gout symptoms and illness concerns, as well as consequences, when using the simplified definition.

CONCLUSION

Using either definition, 6 months of colchicine prophylaxis when initiating ULT does not provide an advantage in the fulfillment of gout remission. People fulfilling either definition report fewer symptoms, less concern about their gout, and, when using the simplified definition, are less affected by gout.

Effective xanthine oxidase inhibitor urate lowering therapy in gout is linked to an emergent serum protein interactome of complement and inflammation modulators

Urate-lowering treatment (ULT) to target with xanthine oxidase inhibitors (XOIs) paradoxically causes early increase in gouty arthritis flares. Because delayed reduction in flare burden is mechanistically unclear, we tested for ULT inflammation responsiveness markers. Unbiased proteomics analyzed blood samples (baseline, 48 weeks ULT) in two, independent ULT out trial cohorts (n = 19, n = 30). STRING-db and multivariate analyses supplemented determinations of altered proteins via Wilcoxon matched pairs signed rank testing in XOI ULT responders. Mechanistic studies characterized proteomes of cultured XOI-treated murine bone marrow macrophages (BMDMs). At 48 weeks ULT, serum urate normalized in all gout patients, and flares declined in association with significantly altered proteins (p < 0.05) in clustering and proteome networks in sera and peripheral blood mononuclear cells. Sera demonstrated altered complement activation and regulatory gene ontology biologic processes. In both cohorts, a treatment-emergent serum interactome included key gouty inflammation mediators (C5, IL-1B, CXCL8, IL6). Last, febuxostat treatment decreased complement activation biologic process proteins in cultured BMDMs. Reduced gout flares are linked with a XOI treatment-emergent serum protein interactome that includes inflammation regulators, associated with altered complement activation and regulatory biologic processes. Serum and leukocyte proteomics could help identify when gouty inflammatory processes begin to subside in response to ULT.Trial Registration: ClinicalTrials.gov Identifier NCT02579096, posted October 19, 2015.

Predicting Gout Flares in People Starting Allopurinol Using the Start-Low Go-Slow Dose Escalation Strategy

OBJECTIVE

The study objective was to determine predictors of gout flare when commencing allopurinol using the "start-low go-slow" dose escalation strategy.

METHODS

A post hoc analysis of a 12-month double-blind placebo-controlled noninferiority trial with participants randomized 1:1 to colchicine 0.5 mg daily or placebo for the first six months was undertaken. Multivariate logistic regression models were used to identify independent predictors of gout flares in the first and last six months of the trial.

RESULTS

Multivariable analysis revealed a significant association between risk of a gout flare in the first six months and flare in the month before starting allopurinol (odds ratio [OR] 2.65, 95% confidence interval [CI] 1.36-5.17) and allopurinol 100 mg starting dose (OR 3.21, 95% CI 1.41-7.27). The predictors of any gout flares in the last six months of the trial, after stopping colchicine or placebo, were having received colchicine (OR 2.95, 95% CI 1.48-5.86), at least one flare in the month before stopping study drug (OR 5.39, 95% CI 2.21-13.15), and serum urate ≥0.36 mmol/L at month 6 (OR 2.85, 95% CI 1.14-7.12).

CONCLUSION

Anti-inflammatory prophylaxis when starting allopurinol using the "start-low go-slow" dose escalation strategy may be best targeted at those who have had a gout flare in the month before starting allopurinol and are commencing allopurinol 100 mg daily. For those with ongoing gout flares during the first six months of starting allopurinol who have not yet achieved serum urate target, a longer period of prophylaxis may be required.

Controversies and practical management of patients with gout and chronic kidney disease

Uric acid is a toxin retained with advancing kidney disease. Clinical manifestations of hyperuricemia include gout and systemic inflammation that are associated with increased risk of cardiovascular mortality. As many as one-third of all patients with chronic kidney disease have a history of gout, yet <25% of these patients are effectively treated to target serum urate levels of ≤6 mg/dl. A major reason for ineffective management of gout and hyperuricemia is the complexity in managing these patients, with some medications contraindicated and others requiring special dosing, potential drug interactions, and other factors. Consequently, many nephrologists do not primarily manage gout despite it being a common complication of chronic kidney disease, leaving management to the primary physician or rheumatologist. We believe that kidney specialists should consider gout as a major complication of chronic kidney disease and actively manage it in their patients. Here, we present insights from nephrologists and rheumatologists for a team approach to gout management that includes the nephrologist.

Identifying the association between serum urate levels and gout flares in patients taking urate-lowering therapy: a post hoc cohort analysis of the CARES trial with consideration of dropout

OBJECTIVE

To investigate gout flare rates based on repeated serum urate (SU) measurements in a randomised controlled trial of urate-lowering therapy (ULT), accounting for dropout and death.

METHODS

We performed a secondary analysis using data from Cardiovascular Safety of Febuxostat or Allopurinol in Patients with Gout, which randomised participants to febuxostat or allopurinol, titrated to target SU <6 mg/dL with flare prophylaxis for 6 months. SU was categorised as ≤3.9, 4.0-5.9, 6.0-7.9, 8.0-9.9 or ≥ 10 mg/dL at each 3-6 month follow-up. The primary outcome was gout flare. Poisson regression models, adjusted for covariates and factors related to participant retention versus dropout, estimated gout flare incidence rate ratios by time-varying SU category.

RESULTS

Among 6183 participants, the median age was 65 years and 84% were male. Peak gout flare rates for all SU categories were observed in months 0-6, coinciding with the initiation of ULT and months 6-12 after stopping prophylaxis. Flare rates were similar across SU groups in the initial year of ULT. During months 36-72, a dose-response relationship was observed between the SU category and flare rate. Lower flare rates were observed when SU ≤3.9 mg/dL and greater rates when SU ≥10 mg/dL, compared with SU 4.0-5.9 mg/dL (p for trend <0.01).

CONCLUSION

Gout flare rates were persistently higher when SU ≥6 mg/dL after the first year of ULT after accounting for censoring. The spike in flares in all categories after stopping prophylaxis suggests a longer duration of prophylaxis may be warranted.

Gout and its management

Gout is a common and treatable chronic disease of monosodium urate crystal deposition. It is experienced as extremely painful episodes of joint inflammation that impact all aspects of the person's life. This Clinical Perspectives article provides an update on gout diagnosis, medications and strategies to improve the quality of gout care.

Sustained xanthine oxidase inhibitor treat to target urate lowering therapy rewires a tight inflammation serum protein interactome

Background

Effective xanthine oxidoreductase inhibition (XOI) urate-lowering treatment (ULT) to target significantly reduces gout flare burden and synovitis between 1-2 years therapy, without clearing all monosodium urate crystal deposits. Paradoxically, treat to target ULT is associated with increased flare activity for at least 1 year in duration on average, before gout flare burden decreases. Since XOI has anti-inflammatory effects, we tested for biomarkers of sustained, effective ULT that alters gouty inflammation.

Methods

We characterized the proteome of febuxostat-treated murine bone marrow macrophages. Blood samples (baseline and 48 weeks ULT) were analyzed by unbiased proteomics in febuxostat and allopurinol ULT responders from two, independent, racially and ethnically distinct comparative effectiveness trial cohorts (n=19, n=30). STRING-db and multivariate analyses supplemented determinations of significantly altered proteins via Wilcoxon matched pairs signed rank testing.

Results

The proteome of cultured IL-1b-stimulated macrophages revealed febuxostat-induced anti-inflammatory changes, including for classical and alternative pathway complement activation pathways. At 48 weeks ULT, with altered purine metabolism confirmed by serum metabolomics, serum urate dropped >30%, to normal (<6.8 mg/dL) in all the studied patients. Overall, flares declined from baseline. Treated gout patient sera and peripheral blood mononuclear cells (PBMCs) showed significantly altered proteins (p<0.05) in clustering and proteome networks. CRP was not a useful therapy response biomarker. By comparison, significant serum proteome changes included decreased complement C8 heterotrimer C8A and C8G chains essential for C5b-9 membrane attack complex assembly and function; increase in the NLRP3 inflammasome activation promoter vimentin; increased urate crystal phagocytosis inhibitor sCD44; increased gouty inflammation pro-resolving mediator TGFB1; decreased phagocyte-recruiting chemokine PPBP/CXCL7, and increased monocyte/macrophage-expressed keratin-related proteins (KRT9,14,16) further validated by PBMC proteomics. STRING-db analyses of significantly altered serum proteins from both cohorts revealed a tight interactome network including central mediators of gouty inflammation (eg, IL-1B, CXCL8, IL6, C5).

Conclusions

Rewiring of inflammation mediators in a tight serum protein interactome was a biomarker of sustained XOI-based ULT that effectively reduced serum urate and gout flares. Monitoring of the serum and PBMC proteome, including for changes in the complement pathway could help determine onset and targets of anti-inflammatory changes in response to effective, sustained XOI-based ULT.Trial Registration: ClinicalTrials.gov Identifier: NCT02579096.

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.