Pegloticase Achieves Complete Gout Remission in 43% of Patients After 52 Weeks of Treatment
Key Insights
Post hoc analysis of the MIRROR trial demonstrates that 43.2% of patients with uncontrolled gout (search) achieved complete remission after 52 weeks of pegloticase treatment with methotrexate cotherapy.
The phase 4 FORWARD trial shows that monthly higher-dose pegloticase (16 mg or 30 mg every 4 weeks) maintains comparable efficacy to standard dosing while reducing treatment burden.
Nearly 99% of patients maintained sustained serum urate levels below 6 mg/dL at week 52, with progressive improvement in remission criteria throughout treatment.
A post hoc analysis of the MIRROR trial reveals that pegloticase, a recombinant pegylated uricase, achieved complete gout (search) remission in 43.2% of patients with uncontrolled gout after 52 weeks of treatment. The findings, led by Dr. Yael Klionsky from Wake Forest University School of Medicine (search), demonstrate the potential for sustained disease control in patients who had previously failed conventional therapies.
MIRROR Trial Results Show Progressive Improvement
The MIRROR trial was a phase 4, multicenter, placebo-controlled, randomized clinical trial that enrolled 145 patients with uncontrolled gout (search), defined as elevated serum urate levels (≥7 mg/dL), oral urate-lowering therapy inefficacy or intolerance, and ongoing signs or symptoms of gout. Patients were randomly assigned in a 2:1 ratio to receive either oral methotrexate (15 mg/week) or placebo as cotherapy to pegloticase (8 mg infusion every 2 weeks) for up to 52 weeks.
Of the 90 patients who remained on treatment through week 52, 13.3% achieved gout (search) remission at week 24, which increased to 43.2% by week 52 using a comprehensive 6-criteria definition. When applying a simplified 3-criteria definition recently proposed by the Gout, Hyperuricemia (search) and Crystal Arthropathy Network (G-CAN), remission rates were even higher: 36.7% at week 24 and 70.3% at week 52.
The study population had a mean age of 54.8 years and an average gout (search) history of 14 years. Investigators found that 98.9% of patients maintained sustained serum urate levels below 6 mg/dL at week 25, with 98.6% sustaining this level at week 52.
Tophus Resolution Proves Most Challenging
The analysis revealed that while most patients showed improvement across remission criteria, tophus resolution remained the most difficult to achieve. Only 34% of patients met the tophus criterion at week 24, increasing to 68.3% at week 52. In contrast, most patients reported low gout (search)-related pain (73%), had low disease burden (74.3%), and had not experienced a gout flare in the previous three months (89.2%) by the end of treatment.
"This demonstrates the vital importance of proper serum urate management, and not just flare and pain management, in patients with gout (search)," wrote Klionsky and colleagues. "Further, this study begins to demonstrate the usefulness of a standardized gout remission definition in defining a clear goal for therapy in both patients and physicians."
FORWARD Trial Explores Monthly Dosing
Complementing these findings, the phase 4 FORWARD trial investigated whether monthly, higher doses of pegloticase could maintain efficacy while reducing treatment burden. The study, presented at the European Alliance of Associations for Rheumatology (EULAR) Congress 2025, enrolled 51 patients with uncontrolled gout (search) who received either 16 mg or 30 mg of pegloticase every 4 weeks with methotrexate cotherapy.
Dr. Orrin Troum from the University of Southern California and colleagues found that 68.0% of the 16-mg cohort and 73.1% of the 30-mg cohort achieved the primary endpoint of serum urate-lowering response at month 6. Among the 36 patients who continued into the extension period, 88.2% of the 16-mg cohort and 68.4% of the 30-mg cohort maintained serum urate response during month 12.
Safety Profile Remains Consistent
The safety profile of monthly dosing appeared consistent with the established pegloticase safety data. Infusion reaction rates, including anaphylaxis, were 16.0% in the 16-mg cohort and 11.5% in the 30-mg cohort at week 48. Notably, no infusion reactions occurred after week 24, consistent with the safety profile observed in the MIRROR trial.
Both cohorts maintained a median of 100% of time with sustained serum urate levels below 6 mg/dL from day 1 to week 24 or day 1 to week 48. The investigators noted that if proper discontinuation criteria had been applied throughout the study, the infusion reaction rate would have been approximately 8% in both groups.
These findings suggest that pegloticase, particularly when combined with methotrexate cotherapy, represents a significant advancement in achieving sustained gout (search) remission for patients with severe, treatment-refractory disease. The potential for monthly dosing could further improve treatment logistics and patient adherence while maintaining therapeutic efficacy.