Background/Purpose: In replicate, 6-month, randomized, placebo-controlled Phase 3 clinical trials a subgroup of patients with treatment-refractory chronic gout (RCG) who received pegloticase infusions (8 mg) every 2 weeks (q2wk) demonstrated statistically significant improvements in multiple patient-reported outcome (PRO) measures derived from the HAQ and SF-36. Patients who showed sustained urate-lowering (defined as responders in the blinded trials) could continue treatment for up to an additional 2.5 years in an open-label extension (OLE) study, thus providing data on health-related quality of life (HRQoL) with long-term pegloticase administration in a responder cohort.

Methods: The OLE enrolled patients at 46 centers in the US, Mexico and Canada. Patients enrolled in the blinded trials were >18 years of age, with baseline uric acid (UA) ≥8 mg/dL and at least one of the following: 3 or more self-reported gout flares during the prior 18 months, 1 or more tophi, or gouty arthropathy (defined clinically or radiographically) and contraindication to allopurinol or failure to normalize UA during 3 or more months of treatment at the maximum medically appropriate dose. Pegloticase dosing regimen (8mg q2wks or q4wks) was determined at study entry and could be adjusted twice during the trial. All patients received prophylaxis for infusion reactions (IRs) and flares. A responder was defined as uric acid levels <6 mg/dL for at least 80% of the time during months 3 and 6. Data from the final visit of the blinded trials was used as the baseline value for the OLE study. Subjects completed the SF-36 and HAQ-DI at 3, 6, 12, 18, 24 and 30 months.

Results:  57 patients receiving q2wk pegloticase completed the blinded trials (36 responders, 29 non-responders). 35 of the 36 responders entered the OLE study; 21 continued with q2wk dosing and 14 elected once monthly dosing at study entry. The table presents mean change from baseline for multiple HRQoL measures.

Conclusion: Pegloticase treatment during the OLE was associated with improvements in PROs for an additional 2.5 years among patients identified as urate responders during the first 6 months of blinded treatment.