• Percentage of Subjects Whose Serum Urate Level Decreased to <6.0 mg/dL at the Day 7 Visit. [ Time Frame: Day 7. ] [ Designated as safety issue: No ]
• Percentage of Subjects Whose Serum Urate Level Decreased to <6.0 mg/dL at the Day 14 Visit. [ Time Frame: Day 14. ] [ Designated as safety issue: No ]
• Percentage of Subjects Whose Serum Urate Level Decreased to <6.0 mg/dL at the Day 21 Visit. [ Time Frame: Day 21. ] [ Designated as safety issue: No ]
• Percent Change in Serum Urate Levels From Baseline to the Day 7 Visit. [ Time Frame: Baseline and Day 7. ] [ Designated as safety issue: No ]
• Percent Change in Serum Urate Levels From Baseline to the Day 14 Visit. [ Time Frame: Baseline and Day 14. ] [ Designated as safety issue: No ]
• Percent Change in Serum Urate Levels From Baseline to the Day 21 Visit [ Time Frame: Baseline and Day 21. ] [ Designated as safety issue: No ]
• Percent Change in Serum Urate Levels From Baseline to the Day 28 Visit. [ Time Frame: Baseline and Day 28. ] [ Designated as safety issue: No ]
• Maximum Percent Change in Serum Urate Level From Baseline During the Entire Treatment Period. [ Time Frame: Baseline and Any visit (Day 7, 14, 21,or 28) ] [ Designated as safety issue: No ]
• Percent Change in 24-hour Urine Uric Acid Level From Baseline to Day 28. [ Time Frame: Baseline and Day 28. ] [ Designated as safety issue: No ]

The purpose of this study is to determine the efficacy of febuxostat in reducing serum urate levels in subjects with gout.

Gout is a chronic urate crystal deposition disorder, which if left untreated may result in progressive disease characterized by joint and bone destruction from tophaceous deposits and renal impairment due to gouty nephropathy. Hyperuricemia, defined as a serum urate concentration of >7.0 milligrams per deciliter (mg/dL), is the underlying metabolic aberration leading to urate crystal deposition in gout. Gout has several clinical presentations, including: recurrent acute attacks of inflammatory arthritis; deposition of monosodium urate monohydrate crystals in joints, bones and even parenchymal organs (tophaceous gout); renal impairment; and uric acid nephrolithiasis. As serum urate levels increase beyond >7.0 mg/dL, the risks for gouty arthritis or for renal calculi increase.

Currently allopurinol is the only xanthine oxidase inhibitor available. Allopurinol is the agent of choice for reduction of serum urate levels in patients with: uric acid overproduction; unresponsive or intolerant to uricosuric agents; impaired renal function; uric acid urolithiasis; or tophi.

Febuxostat (TMX-67) is a non-purine selective xanthine oxidase inhibitor being developed as an orally administered agent for management of hyperuricemia in patients with gout.

• Drug: Placebo
• Drug: Febuxostat

• Becker MA, Schumacher HR Jr, Wortmann RL, MacDonald PA, Palo WA, Eustace D, Vernillet L, Joseph-Ridge N. Febuxostat, a novel nonpurine selective inhibitor of xanthine oxidase: a twenty-eight-day, multicenter, phase II, randomized, double-blind, placebo-controlled, dose-response clinical trial examining safety and efficacy in patients with gout. Arthritis Rheum. 2005 Mar;52(3):916-23.
• Colwell HH, Hunt BJ, Pasta DJ, Palo WA, Mathias SD, Joseph-Ridge N. Gout Assessment Questionnaire: Initial results of reliability, validity and responsiveness. Int J Clin Pract. 2006 Oct;60(10):1210-7. Epub 2006 Aug 15.

Inclusion Criteria:

• Hyperuricemia (serum uric acid ≥8.0 mg/dL).
• Must meet American College of Rheumatology criteria for gout.
• Must have adequate renal function (serum creatinine <1.5 mg/dL).
• Females of childbearing potential who are sexually active must agree to use adequate contraception, and can neither be pregnant nor lactating from Screening throughout the duration of the study.

Exclusion Criteria:

• History of xanthinuria
• Alcohol consumption >14/week
• Has a history of significant concomitant illness.
• Has active liver disease.
• Has a body mass index greater than 50 kilogram per meter² (kg/m²)
• Any other significant medical condition that would interfere with the treatment, safety or compliance with the protocol, as defined by the investigator.