Pegloticase Infusion Research Articles

Pegloticase-Induced Rapid Uric Acid Lowering and Kidney and Cardiac Health Markers in Youth-Onset Type 2 Diabetes: A Pilot Clinical Trial

Rationale & ObjectiveElevated serum uric acid (SUA) is a risk factor for incident hypertension and diabetic kidney disease in young persons with type 2 diabetes (T2D), particularly men. The acute benefit of aggressively lowering SUA on kidney and cardiovascular function in this population remains underexplored. This study was conducted to investigate the impact of a single pegloticase infusion on kidney and cardiovascular function. Study DesignAn open-label pilot trial. Setting & ParticipantsThe study involved 10 young adult males with youth-onset T2D and SUA levels ≥5 mg/dL. Intervention(s)Participants received a single infusion of pegloticase (8 mg). Evaluations were conducted using iohexol-based measured glomerular filtration rate (mGFR) and cardiac/kidney MRI before and one week after infusion. OutcomesThe primary outcomes were changes in SUA and mGFR one week after pegloticase infusion. ResultsNine participants (mean [±SD] age 22±5 years, HbA1c 8.6±3.3%, BMI 40.1±11.0 kg/m2, SUA 6.7±1.1 mg/dL) completed the pegloticase infusion and were included in the analysis. One week after the infusion, median [p25,p75] SUA concentrations dropped from 6.4 [5.6,7.6] to 0.5 [0.5,4.6] mg/dL (p=0.01). Mean mGFR increased from 113±20 to 122±19 ml/min per 1.73 m2 (p=0.004). Among responders (SUA reduction ≥3 mg/dL), an increase in mGFR correlated with an increase in renal artery blood flow (r:0.60, p=0.24) and decrease in SUA (r:-0.79, p=0.05). Mean MRI peak longitudinal cardiac strain additionally decreased from 15.4±2.2 to 13.1±2.2 % (p=0.03) in these responders. LimitationsThe pilot nature of the study and the small sample size limit the generalizability of the findings. ConclusionsIn young adult males with T2D, a single pegloticase infusion decreased SUA levels, which increased mGFR and was strongly associated with increased renal blood flow and impaired cardiac global longitudinal strain. Further research is required to assess the long-term efficacy and safety of pegloticase in patients with T2D.

Real-World Effectiveness of Pegloticase Associated With Use of Concomitant Immunomodulatory Therapy.

The objective of this study was to ascertain pegloticase persistence and adverse events associated with concomitant immunomodulatory drug treatment in patients with gout. We conducted a retrospective analysis of patients with gout using the American College of Rheumatology's Rheumatology Informatics System for Effectiveness registry from January 2016 through June 2020. The first pegloticase infusion defined the index date. Based on concomitant immunomodulatory drug treatment, we identified three exposure groups: (1) immunomodulatory drug initiators (patients initiating an immunomodulatory prescription ±60 days from the index date), (2) prevalent immunomodulatory drug recipients (patients receiving their first immunomodulatory drug prescription >60 days before the index date with at least one prescription within ±60 days of the index date), and (3) immunomodulatory nonrecipients (patients receiving pegloticase without concomitant immunomodulatory drugs). We calculated the proportion of patients who achieved serum urate levels ≤6 mg/dL and who had laboratory abnormalities (white blood cell count <3.4 x 109/L, platelet count <135,000, hematocrit level <30%, alanine aminotransferase or aspartate aminotransferase level ≥1.5 times the upper limit normal value) within 180 days after the index date. Cox regression analyzed time to pegloticase discontinuation, controlling for potential confounders. We identified 700 pegloticase recipients (91 immunomodulatory drug initiators, 33 prevalent immunomodulatory drug recipients, and 576 nonrecipients), with a median follow-up of 14 months. Immunomodulatory drug recipients were less likely to discontinue pegloticase. The adjusted hazard ratios of pegloticase discontinuation associated with concomitant immunomodulatory drug initiation and prevalent treatment were 0.52 (95% confidence interval [CI] 0.37-0.75) and 0.69 (95% CI 0.42-1.16), respectively. Laboratory abnormalities were uncommon (<5%) and were not higher in concomitant immunomodulatory drug treatment. Consistent with clinical trials, results from this large observational registry suggest that concomitant immunomodulatory drug treatment improves pegloticase persistence.

Monosodium urate crystal depletion and bone erosion remodeling during pegloticase treatment in patients with uncontrolled gout: Exploratory dual-energy computed tomography findings from MIRROR RCT

ObjectiveMonosodium-urate (MSU) crystal deposits can be visualized and quantified with dual-energy CT (DECT). Pegloticase lowers serum urate (SU) in uncontrolled gout patients, with methotrexate (MTX) co-therapy recommended to increase SU-lowering response rate and decrease infusion reaction risk. The literature on serial DECT-imaging during pegloticase+MTX co-therapy is sparse, with only 2 prior cases of rapid MSU deposition depletion with subsequent bone-erosion remodeling reported from a small open-label trial. Here, we report DECT findings during pegloticase treatment in a larger number of patients from a randomized controlled trial to confirm bone-erosion remodeling that follows MSU depletion with pegloticase. The influence of length-of-therapy is also explored. MethodsPatients received pegloticase (8mg every 2weeks)+MTX (15mg/week orally) or pegloticase+placebo (PBO) during the MIRROR RCT trial. A subset underwent DECT-imaging on Day1 (first pegloticase infusion) and at Weeks 14, 24, and 52. Patients with paired baseline-Week 52 images were included. Imaged regions with baseline MSU-crystal volume (VMSU)<0.5cm3 were excluded to minimize artifact contributions. VMSU and bone-erosion remodeling were assessed. ResultsEight patients (6 MTX, 2 PBO) were included. Included patients had received 52weeks (5 MTX), 42weeks (1 PBO), and 6weeks (1 MTX, 1 PBO) of pegloticase therapy. Patients who prematurely discontinued pegloticase maintained SU<6mg/dL on allopurinol (n=2)/febuxostat (n=1). At Week 52, VMSU had markedly decreased in both the pegloticase+MTX and pegloticase+PBO treatment groups, with faster depletion during pegloticase therapy. Bone-erosion remodeling was observed in 29/42 (69%) evaluated erosions: 29 (69%) size decrease, 4 (9.5%) recortication, 3 (7.1%) new bone formation. ConclusionRapid VMSU depletion during pegloticase therapy was observed with concomitant bone remodeling within 1year. Following pegloticase discontinuation, VMSU reduction slowed or stopped even when SU was maintained<6mg/dL with oral ULT. Clinical trial registrationNCT03994731.

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

BackgroundUncontrolled/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.MethodsAdults 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.ResultsFourteen 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.ConclusionPegloticase + methotrexate co-therapy resulted in sustained SU-lowering with meaningful improvements in clinical measures, urate burden, and patient-reported outcomes.Trial registrationClinicalTrials.gov (NCT03635957)

Community Practice Experiences with a Variety of Immunomodulatory Agents Co-Administered with Pegloticase for the Treatment of Uncontrolled Gout.

ObjectivePatients with uncontrolled/refractory gout have heavy disease burden, but few treatment options. Pegloticase lowers serum urate (SU), but anti-drug antibodies can limit treatment efficacy. Evidence supports immunomodulator-pegloticase co-administration to increase sustained urate-lowering rates, but published cases are limited. This study investigated experience with pegloticase-immunomodulation co-therapy at two community rheumatology practices.MethodsPatients initiating pegloticase with immunomodulation in 2017 or later were included. Patient/treatment characteristics and proportion of responders (≥ 12 pegloticase infusions, SU < 6 mg/dl at infusion-12) were examined. Patients on therapy at data collection with < 12 infusions were excluded from response analyses. eGFR before and after therapy was examined.ResultsThirty-four patients (79% male, 62.4 ± 16.3 years) with uncontrolled gout (SU = 9.1 ± 2.0 mg/dl, 91% tophaceous) were included. Most-reported comorbidities were hypertension (76%), obesity (71%), osteoarthritis (68%), and CKD (47%). Pre-therapy eGFR was 65.4 ± 25.2 ml/min/1.73 m2 (41% eGFR < 60 ml/min/1.73 m2). All patients initiated immunomodulation before (5.3 ± 3.0 weeks, n = 32) or at (n = 2) first pegloticase infusion. Subcutaneous methotrexate (15.4 ± 4.9 mg/week, n = 20), oral methotrexate (15.3 ± 3.6 mg/week, n = 9), mycophenolate mofetil (1000 mg/day, n = 3), and azathioprine (100 mg/day, n = 2) were administered. Patients received 14.6 ± 7.1 infusions over 28.5 ± 14.9 weeks. Overall response rate was 89%, ranging among immunomodulators (subcutaneous methotrexate: 93%, oral methotrexate: 89%, mycophenolate mofetil: 100%, azathioprine: 50%). On average, eGFR increased during therapy (+ 10.3 ± 16.9 ml/min/1.73 m2), with CKD stability/improvement in 85%. Nineteen patients (56%) experienced gout flares. No infusion reactions or infections were noted. No new safety concerns were identified.ConclusionsThese real-world findings provide further support for increased pegloticase response rates when co-treatment with immunomodulating therapy is used.

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

BackgroundPublications 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.MethodsUncontrolled 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.ResultsFourteen 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.ConclusionsPegloticase + 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 registrationClinicalTrials.gov, NCT03635957. Registered on 17 August 2018.

Interventions for tophi in gout.

Interventions for tophi in gout.

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

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. 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. 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. 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.

THU0416 PEGLOTICASE RESPONSE IMPROVEMENT BY CO-TREATMENT WITH METHOTREXATE: RESULTS FROM THE MIRROR OPEN-LABEL CLINICAL TRIAL IN PATIENTS WITH UNCONTROLLED GOUT

Background:Gout is a painful inflammatory arthritis caused by persistently elevated serum uric acid (sUA) levels. Pegloticase, an infused recombinant PEGylated uricase, rapidly lowers sUA levels by converting uric acid to allantoin, a water-soluble molecule that is readily excreted by the kidneys. In the phase 3 clinical trials, 42% of patients1dosed with pegloticase every two weeks maintained sUA levels below 6.0 mg/dL during months 3 and 6 of pegloticase treatment. The loss of pegloticase efficacy has been attributed to the development of anti-drug antibodies (ADAs)1-3and these ADAs have been associated with infusion reactions (IRs).1,2Case reports4and prospective case series5, 6indicate that methotrexate (MTX) may allow patients to attain more complete therapeutic benefits, presumably through attenuation of pegloticase immunogenicity. The current study prospectively examines the efficacy and safety of MTX-pegloticase co-therapy in patients with uncontrolled gout.Objectives:To assess efficacy and safety of concomitant pegloticase and MTX therapy in patients with uncontrolled gout.Methods:Adult patients with uncontrolled gout who were beginning pegloticase therapy were considered for enrollment in this ongoing multicenter, open-label, efficacy and safety study of pegloticase with MTX co-treatment (NCT03635957). Patients were administered oral MTX (15 mg/week) and folate (1 mg/day) 4 weeks prior to the first pegloticase infusion (Day 1) and throughout the pegloticase treatment period. Blood was drawn prior to each infusion to measure sUA level, monitor clinical parameters, and examine for ADA development. All patients followed typical IR prophylaxis protocols (fexofenadine one day before and the morning of each infusion and acetaminophen and IV corticosteroid the morning of each infusion). Patients also received gout flare prophylaxis with either NSAIDs, colchicine or prednisone initiated at least 1 week prior to Day 1. The primary study outcome was the proportion of responders, defined as sUA &lt;6 mg/dL for at least 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:A total of 17 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 months timepoint, 11/14 (78.6%, 95%CI 49.2-95.3%) met the responder definition, with 3 patients discontinuing after meeting stopping rules (pre-infusion sUA values greater than 6 mg/dL at 2 consecutive scheduled visits). All patients tolerated MTX. One serious AE of bacterial sepsis occurred (resolved). AEs that occurred in &gt;1 patient during the co-treatment period were: diarrhea and upper respiratory tract infection in 3 patients each, sinusitis, muscle strain, and hypertension in 2 patients each. Gout flares occurred in 12/14 (85.7%) patients. No new safety concerns were identified.Conclusion:An increased proportion of patients maintained therapeutic response at 6 months when treated concomitantly with MTX and pegloticase (78.6%) when compared to the previously reported 42% using pegloticase alone.1These results support and reflect the improved response rates demonstrated in two prior case series.5,6A definitive randomized double-blinded trial evaluating pegloticase with MTX vs. pegloticase with placebo is ongoing.

Concomitant immunosuppressant use with pegloticase in patients with tophaceous gout - A case series

Introduction: Treatment of tophaceous gout with pegloticase is often complicated by the production of anti-pegloticase antibodies. These antibodies result in increased risk of infusion reactions, loss of drug efficacy, and high discontinuation rate. Steroids are used in premedication to reduce potential infusion reactions; however prolonged usage of steroids is associated with significant adverse effects. Objective: To describe the use of immunosuppressants to reduce the incidence of infusion reactions with pegloticase treatment and the potential reduction of steroid use in premedication. Methods: We report seven cases of immunosuppressant use, initiated on the day of the first pegloticase infusion, as an adjunct to treatment with pegloticase for tophaceous gout. Results: Patient 1 was treated for tophaceous gout with oral methotrexate initiated at his first infusion. Low serum urate levels were achieved but urate increased on two occasions after two separate lapses in methotrexate compliance. In each instance, initiation of a higher dose of methotrexate restored pegloticase response. The patient tolerated all treatments without infusion reaction. Patients 2-6 were treated for tophaceous gout with oral methotrexate initiated at their first infusions. For Patient 2, methotrexate was switched to azathioprine at her fifth infusion due to fatigue. All five patients achieved low serum uric acid (sUA) levels, completed their treatments, and did not experience infusion reactions. Patient 7 was treated for tophaceous gout with oral cyclosporine initiated at his first infusion. Methotrexate was not used due to elevated liver function enzymes at baseline. He achieved a low sUA level and was able to complete his treatment without experiencing an infusion reaction. All of the patients were able to decrease their steroid use in pre-medication. Six of the seven were able to discontinue steroid use in pre-medication without developing infusion reactions. Conclusion: Concomitant use of immunosuppressive therapy with pegloticase may play a role in preventing infusion reactions, allow reduction of steroids in pre-medication, and result in improved outcomes. We have demonstrated that immunosuppressive therapy may be initiated on the day of the first infusion. Additionally, therapy does not seem to be confined to a single immunosuppressant; thus, immunosuppressive therapy may be tailored to a patient’s needs. The use of concomitant immunosuppressants with pegloticase treatment warrants further study.

Infusion-related reactions with pegloticase, a recombinant uricase for the treatment of chronic gout refractory to conventional therapy.

BackgroundIn clinical trials of pegloticase, a PEGylated uricase developed for treatment of gout refractory to conventional therapy, infusion-related reactions (IRs) were the second most frequent adverse event reported.ObjectiveThe objective of this study was to provide a detailed account of IRs with pegloticase therapy.MethodsData from 2 replicate, 6-month randomized trials and an open-label extension study were pooled. Infusions of pegloticase (8 mg) were administered biweekly or monthly; all patients received prophylaxis (antihistamine, acetaminophen, and corticosteroid) and were tested for urate levels prior to each infusion. An IR was defined by protocol as any otherwise unexplained adverse event or cluster of temporally related events occurring during or within 2 hours of infusion.ResultsInfusion-related reactions occurred in 94 (45%) of 208 patients receiving pegloticase; 10 patients reported IRs at first infusion and 84 during subsequent infusions. Chest discomfort (15%), flushing (12%), and dyspnea (11%) were the most common symptoms. Most IRs were rated mild or moderate; 7% were rated severe. All IRs resolved with slowing, interrupting, or stopping the infusion. No patient required blood pressure or ventilatory support. Infusion-related reactions were associated with loss of pegloticase urate-lowering efficacy: 91% of all IRs occurred in patients with preinfusion serum uric acid concentrations (sUA) greater than 6 mg/dL. For patients sustaining preinfusion sUA of less than 6 mg/dL, IRs occurred in fewer than 1 per 100 infusions.ConclusionsPhase 3 trial data combined with post hoc analyses demonstrated that knowledge of sUA preceding each pegloticase infusion and cessation of therapy when urate-lowering efficacy is lost provide a means to optimize the safety of pegloticase in clinical practice.

Interventions for tophi in gout.

Tophi develop in untreated or uncontrolled gout. Their presence can lead to severe and potentially fatal complications. To date there have been no systematic reviews focused on the management of tophi in gout. To assess the benefits and harms of non-surgical and surgical treatments for the management of tophi in gout. We searched three databases: the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE. We handsearched American College of Rheumatology (ACR) and European League against Rheumatism (EULAR) abstracts from 2010 to 2011, references from included studies and trial registries. We completed the most recent search on 20 May 2013. All published randomised controlled trials (RCTs) or controlled clinical trials with quasi-randomised methods of allocating participants to treatment examining interventions for tophi in gout in adults. Possible interventions included urate-lowering pharmacological treatment (e.g. benzbromarone, probenecid, allopurinol, febuxostat, pegloticase), surgical removal or other interventions such as haemodialysis. Two review authors extracted data from titles, abstracts and selected studies for detailed review, and extracted data and risk of bias independently. Major outcomes were number of participants with complete resolution of tophi, number of study participant withdrawals due to adverse events, joint pain reduction, function, quality of life, serum urate normalisation and total adverse events. Only one study, at low risk of all biases, met the inclusion criteria. This was the pooled results from two RCTs (225 participants, 145 with tophi at baseline) randomised to one of three arms; pegloticase infusion every two weeks (biweekly), monthly pegloticase infusion (pegloticase infusion alternating with placebo infusion every two weeks) and placebo. Moderate-quality evidence from one study indicated that biweekly pegloticase 8 mg infusion reduced tophi in the subset of participants with tophi, but increased withdrawals due to adverse events in all participants, and monthly infusion appeared to result in less benefit.Biweekly pegloticase treatment resulted in resolution of tophi in 21/52 participants compared with 2/27 who received placebo (risk ratio (RR) 5.45, 95% confidence intervals (CI) 1.38 to 21.54; number needed to treat for an additional beneficial outcome (NNTB) 3 (95% CI 2 to 6).Eleven of 52 participants with monthly pegloticase treatment had complete resolution of one or more tophi compared with 2/27 who received placebo (RR 2.86, 95% CI 0.68 to 11.97).Participant-reported pain relief of 30% or greater, function, quality of life, serum urate normalisation, were reported for all participants but not separately for those with tophi; therefore, we did not include the results.Pegloticase administered biweekly resulted in more withdrawals due to adverse events compared with placebo (15/85 participants with pegloticase versus 1/43 participants with placebo; RR 7.59, 95% CI 1.04 to 55.55; number needed to treat for an additional harmful outcome (NNTH) 7, 95% CI 4 to 17). Pegloticase administered monthly also resulted in more withdrawals due to adverse events than placebo (16/84 participants with pegloticase versus 1/43 participants with placebo; RR 8.19, 95% CI 1.12 to 59.71; NNTH 6, 95% CI 4 to 14). Most withdrawals were due to infusion reactions.Total adverse events were high in all treatment groups: 80/85 participants administered pegloticase biweekly reported an adverse event compared with 41/43 from the placebo group (RR 0.99, 95% CI 0.91 to 1.07); 84/84 participants administered pegloticase monthly reported an adverse event versus 41/43 in the placebo group (RR 1.05, 95% CI 0.98 to 1.14). As 80% of adverse events were due to flares of gout, probably unrelated to the drug treatment per se, this may explain the high rate of adverse events in the placebo group - who were essentially untreated. This study showed pegloticase is probably beneficial in the management of tophi in gout, in terms of resolution of tophi, but with a high risk of adverse infusion reactions. However, there is a need for more RCT data considering other interventions, including surgical removal of tophi.

SAT0376 Uric Acid Levels as a Biomarker of Efficacy and Safety in Patients Treated with Pegloticase: Lessons Learned from us Clinical Experience

BackgroundPegloticase is a recombinant uricase recently approved in the EU for the treatment of severe, debilitating chronic tophaceous gout refractory to xanthine oxidase inhibitors (XOIs) or when XOIs are contraindicated....

Therapeutic perspectives on uricases for gout

Available recombinant uricases (rasburicase, pegloticase) are potent hypouricaemic agents for tophaceous gout, but their long-term use is in question. We have performed a literature review on uricases, using Scirus, PubMed, Science Direct, and several other search engines. We have also consulted the records of drug regulatory authorities and patents on uricases. Rasburicase (Fasturtec®) was approved in Europe for tumour lysis syndrome induced by chemotherapy, in a single daily infusion dose for a maximum of 7days. A retrospective study (n=10) conducted in patients with gout and three clinical cases have shown that infusions spaced over time, over several months, ensure the control of serum uric acid and help to eliminate or significantly reduce the size of tophi. However, repeated gout attacks (despite colchicine) and hypersensitivity reactions (despite corticosteroids) have dampened enthusiasm for its use in gout. Pegloticase was recently approved by the Food and Drug Administration (FDA) for patients with chronic gout, refractory or intolerant to conventional hypouricaemic therapy. A 6month study versus placebo showed that pegloticase (infused at 8mg every 2weeks), induced a significant decrease in plasma uric acid in about 40% of patients (associated with a tendency for tophi dissolution). However, the remaining patients were non-responders, which correlated with the formation of pegloticase antibodies and infusion reactions. Research efforts are needed to develop less immunogenic uricases. In conclusion, some uricases could have an important role in the treatment of gout, for instance as a first-line treatment and over a short period of several months in patients with severe and tophaceous gout to allow rapid tophi dissolution.

Treating gout with pegloticase, a PEGylated urate oxidase, provides insight into the importance of uric acid as an antioxidant in vivo

A high plasma urate concentration (PUA), related to loss of urate oxidase in evolution, is postulated to protect humans from oxidative injury. This hypothesis has broad clinical relevance, but support rests largely on in vitro data and epidemiologic associations. Pegloticase therapy generates H(2)O(2) while depleting urate, offering an in vivo test of the antioxidant hypothesis. We show that erythrocytes can efficiently eliminate H(2)O(2) derived from urate oxidation to prevent cell injury in vitro; during therapy, disulfide-linked peroxiredoxin 2 dimer did not accumulate in red blood cells, indicating that their peroxidase capacity was not exceeded. To assess oxidative stress, we monitored F2-Isoprostanes (F2-IsoPs) and protein carbonyls (PC), products of arachidonic acid and protein oxidation, in plasma of 26 refractory gout patients receiving up to five infusions of pegloticase at 3-wk intervals. At baseline, PUA was markedly elevated in all patients, and plasma F2-IsoP concentration was elevated in most. Pegloticase infusion rapidly lowered mean PUA to < or = 1 mg/dL in all patients, and PUA remained low in 16 of 21 patients who completed treatment. F2-IsoP levels did not correlate with PUA and did not increase during 15 wk of sustained urate depletion. There also was no significant change in the levels of plasma PC. Because refractory gout is associated with high oxidative stress in spite of high PUA, and profoundly depleting uric acid did not increase lipid or protein oxidation, we conclude that urate is not a major factor controlling oxidative stress in vivo.