Superiority of Low‐Dose Benzbromarone to Low‐Dose Febuxostat in a Prospective, Randomized Comparative Effectiveness Trial in Gout Patients With Renal Uric Acid Underexcretion

Objective The predominant mechanism driving hyperuricemia in gout is renal uric acid underexcretion; however, the standard urate‐lowering therapy (ULT) recommendation is first‐line xanthine oxidase inhibitor (XOI), irrespective of the cause of hyperuricemia. This comparative effectiveness clinical trial was undertaken to compare first‐line nontitrated low‐dose benzbromarone (LDBen) uricosuric therapy to XOI ULT with low‐dose febuxostat (LDFeb) in gout patients with renal uric acid underexcretion. Methods We conducted a prospective, randomized, single‐center, open‐label trial in men with gout and renal uric acid underexcretion (defined as fractional excretion of urate <5.5% and uric acid excretion ≤600 mg/day/1.73 m 2 ). A total of 196 participants were randomly assigned to receive LDBen 25 mg daily or LDFeb 20 mg daily for 12 weeks. All participants received daily urine alkalization with oral sodium bicarbonate. The primary end point was the rate of achieving the serum urate target of <6 mg/dl. Results More participants in the LDBen group achieved the serum urate target than those in the LDFeb group (61% compared to 32%, P < 0.001). Rates of adverse events, including gout flares and urolithiasis, did not differ between groups, with the exception of greater transaminase elevation in the LDFeb group (4% for LDBen compared to 15% for LDFeb, P = 0.008). Conclusion Compared to LDFeb, LDBen has superior urate‐lowering efficacy and similar safety in treating relatively young and healthy patients with renal uric acid underexcretion–type gout.