Febuxostat: A selective xanthine oxidase inhibitor for the treatment of hyperuricemia and gout

OBJECTIVE: To review the pharmacology, pharmacokinetics, clinical trial data, safety profile, precautions, and place in therapy of febuxostat, a novel nonpurine xanthine oxidase inhibitor in development for the treatment of hyperuricemia and gout. DATA SOURCES: Available studies and abstracts were identified through MEDLINE (1990-November 2006), Science Citation Index, International Pharmaceutical Abstracts, Cochrane Databases, and the American College of Rheumatology and European League Against Rheumatism Web sites. Key search terms were febuxostat, TMX-67, TEI-6720, hyperuricemia, and gout. STUDY SELECTION AND DATA EXTRACTION: All available studies describing the pharmacology of febuxostat were included. Human studies formed the basis for discussion of clinical parameters, including pharmacokinetics, pharmacodynamics, efficacy, and safety of febuxostat. DATA SYNTHESIS: Febuxostat significantly reduces uric acid levels within 2 weeks after initiation of therapy and up to 48% by the end of 104 weeks of therapy. Approximately 60% of patients achieved the primary goal of serum uric acid less than 6 mg/dL during the last 3 months following once-daily administration of febuxostat 80 mg or 120 mg for at least 52 weeks. The most common adverse reactions to febuxostat were abnormal results from liver function tests, diarrhea, headache, arthralgias, and musculoskeletal symptoms. Due to its potency, patients are at an increased risk of experiencing gout flares for at least the first year of therapy. Up to 70% of patients in clinical trials experienced gout flares despite concomitant prophylactic treatment with colchicine or naproxen. Additional clinical trial evidence supports the efficacy and safety of febuxostat in the treatment of hyperuricemia and gout. CONCLUSIONS: Febuxostat is a promising alternative to allopurinol for the treatment of gout and hyperuricemia. The optimal length of prophylactic therapy, clinical significance of abnormal liver function tests results during therapy, and safety in patients with moderate or severe renal insufficiency warrant further investigation.