Topiroxostat
Topiroxostat is a selective xanthine oxidase inhibitor developed for treatment and management of hyperuricemia and gout. Xanthine oxidase, or xanthine oxidoreductase (XOR), regulates purine metabolism, and inhibition of the enzyme results in efficacious reduction of serum urate levels. Xanthine oxidase inhibitors are classified into two groups; purine analogs such as [DB00437] and [DB05262], and non-purine agents which includes topiroxostat. While [DB00437] is considered a first-line therapy in treating hyperuricemic conditions, it is often associated with side effects and ineffective in reducing uric acid levels under recommended dosing regimens. Renal complications are major comorbidities that limit the [DB00437] therapy as dose reductions are recommended. Topiroxostat and its metabolites are shown to be unaffected by renal complications, thus may be effective in patients with chronic kidney diseases. Approved for therapeutic use in Japan since 2013, topiroxostat is marketed under the name Topiloric and Uriadec and is orally administered twice daily.