A Randomized, Double-Blind, Non-Inferiority Study of Febuxostat Versus Allopurinol in Hyperuricemic Chinese Subjects With or Without Gout

Introduction This 24-week randomized, double-blind, non-inferiority study compared the efficacy and safety of febuxostat, a xanthine oxidase inhibitor, with allopurinol using an up-titration method in hyperuricemic Chinese subjects with or without gout. Methods Eligible adults (serum uric acid [SUA] > 7.0 mg/dl with a history of gout, SUA >= 8.0 mg/dl with complications or SUA >= 9.0 mg/dl without complications) were randomized (1:1:1) to febuxostat 40 mg/day, 80 mg/day, or allopurinol 300 mg/day. Starting doses of febuxostat 20 mg/day and allopurinol 100 mg/day were up-titrated, up to 16 weeks, to the randomized doses and maintained to week 24. Primary endpoint was non-inferiority of febuxostat 40 mg/day versus allopurinol 300 mg/day based on the percentage of subjects with SUA <= 6.0 mg/dl at week 24. The same comparison was made between febuxostat 60 mg/day or 80 mg/day versus allopurinol 300 mg/day. Safety assessments included measurement of treatment-emergent adverse events (TEAEs). Results The per-protocol population comprised 472 subjects. Non-inferiority of febuxostat 40 mg/day versus allopurinol 300 mg/day was not demonstrated based on the protocol-defined margin of - 10% (44.7 vs. 50.0%; - 5.3% difference; 95% confidence interval [CI]: - 16.4%, 5.8%); however, superiority over allopurinol 300 mg/day was demonstrated for febuxostat 60 mg/day at week 16 (66.3 vs. 51.2%; a 15.0% difference; 95% CI: 4.2%, 25.9%) and febuxostat 80 mg/day at week 24 (70.0 vs. 50.0%; a 20.0% difference; 95% CI: 9.3%, 30.7%). The frequency of TEAEs was similar across groups, with gout flares occurring frequently. Conclusions Using a novel dose-titration method, although the primary endpoint of non-inferiority of febuxostat 40 mg/day versus allopurinol 300 mg/day was not reached, non-inferiority and superiority of febuxostat 60 mg/day and 80 mg/day versus allopurinol 300 mg/day was demonstrated at weeks 16 and 24, respectively. Febuxostat demonstrated an acceptable tolerability profile in the treatment of hyperuricemia in Chinese subjects with or without gout. Funding Astellas Pharma Global Development, Inc.