Ecto-5'-nucleotidase (CD73) is a biomarker for clear cell renal carcinoma stem-like cells.

OBJECTIVES: To assess the benefit of long-term urate-lowering with pegloticase.

METHODS: The results from two, 6-month, randomised controlled trials (RCTs) and their 30-month open-label extension (OLE) were analysed. Efficacy was assessed in urate responders (patients with plasma urate <6.0 mg/dL for ≥80% of assessments around the 3- and 6-month time periods) to the approved regimen (8 mg every 2 weeks [q2w]) and responders to q4w treatment. Assessments included serum urate (sU), Patient Global Assessment (PtGA), tender and swollen joints (TJC and SJC), pain, Health Assessment Questionnaire Disability Index, bodily pain, the Arthritis-Specific Health Index, and reduction of target tophi.

RESULTS: 34 responders to pegloticase in the RCTs were followed throughout the 2.5 years of the OLE. Of these, 20 received 8 mg pegloticase q2w and 14 q4w. The results for patients who received pegloticase q2w indicated significant improvements between RCT baseline and the final OLE evaluation for sU (p<0.0001), PtGA (p<0.0001), TJC (p=0.0001), and SJC (p=0.0014); 61.5%, had complete target tophus resolution. The results for patients treated monthly indicated significant improvements between RCT baseline and the final OLE evaluation for sU (p<0.001), PGA (p=0.0003), TJC (p=0.008), and SJC (p<0.0001);100% had complete target tophus resolution.

CONCLUSIONS: There were significant sustained clinical benefits with long-term pegloticase treatment in patients with chronic refractory gout achieving a urate-lowering effect during the first 6 months of therapy and followed for up to 30 additional months.