Achaia Taltoan, Mercer University College of Pharmacy
Tophaceous gout is a form of advanced gout characterized by persistent arthritis, white-yellow intradermal deposits, and frequent recurrent acute attacks. The 2012 American Rheumatology Association and the European League Against Rheumatism (EULAR) guidelines for gout recommend xanthine oxidase inhibitors, allopurinol, or febuxostat as first line treatment for chronic tophaceous gout with a goal serum urate <6 mg/dL. [1,2] The EULAR and American Rheumatology Association guidelines suggest a goal serum urate < 5 mg/dL for patients with severe gout symptoms, including tophi, chronic arthropathy, and frequent attacks.  Evidence shows that approximately 40% of patients treated with allopurinol achieve serum urate levels less than 6 mg/dL, and about 48% of febuxostat patients can maintain target serum urate levels for three consecutive months. [3,4]
Lesinurad is a novel selective urate anion absorption inhibitor approved for combination with a xanthine oxidase inhibitor for gout patients whose serum urate targets are not achieved with xanthine oxidase inhibitor monotherapy. The CLEAR 1 and CLEAR 2 trial assessed the use of lesinurad with allopurinol in patients who failed to meet serum urate goals with monotherapy. [5,6] However, no trial assessed the combination of febuxostat and lesinurad in patients who failed xanthine oxidase monotherapy, until the CRYSTAL trial was conducted.