A Phase 3 Randomized, Double-Blind, Multicenter, Placebo- Controlled Study to Assess the Efficacy and Safety of Lesinurad Monotherapy Compared to Placebo in Subjects With Gout and an Intolerance or Contraindication to a Xanthine Oxidase Inhibitor

Allopurinol is the standard of care for the treatment of gout. In practice, approximately 20% of patients report side effects with allopurinol and 5% discontinue allopurinol due to side effects. Allopurinol can cause gastrointestinal intolerance, such as nausea and diarrhea, which appears to be dosedependent. Rash develops in about 2% of patients treated with allopurinol, and in about 20% of patients treated with allopurinol and ampicillin or amoxicillin. Allopurinol hypersensitivity syndrome remains a major concern among physicians. Mortality has been estimated to be up to nearly one quarter of AHS cases, with multiorgan system disease including hepatocellular changes and renal failure being a serious concern. Allopurinol is also relatively contraindicated for use in combination with 6-mercaptopurine and azathioprine, for which 1/4 to 1/3 lower doses must be given in order to avoid hematologic toxicity. Febuxostat, in clinical trials, has shown a similar AE profile to allopurinol. Liver function abnormalities, nausea, arthralgia and rash were the most commonly reported AEs. In postmarketing experience, Stevens Johnson Syndrome and hypersensitivity rashes have been reported (febuxostat prescribing information). Withdrawals due to AEs were similar in frequency to allopurinol as well. Relative contraindications in combination with 6-mercaptopurine and azathioprine are similar to allopurinol as well. Lesinurad may be an important therapeutic option for patients who either cannot tolerate or who have a contraindication to the use of allopurinol or febuxostat.