The purpose of this study is confirmatory investigation of safety and efficacy of FYU-981 administered orally to hyperuricemic patients with and without gout for 34 or 58 weeks by the method of multicenter, open label and ascending dose regimen.

Inclusion Criteria:

• Hyperuricemic or gout patients
• Serum urate level:

>= 7.0mg/dL in patients with history of gout, or >= 8.0mg/dL in patients with hypertension, diabetes or metabolic syndrome, or >= 9.0mg/dL

Exclusion Criteria:

• Gouty arthritis within two weeks before start of study treatment
• Secondary hyperuricemia
• HbA1c: >= 8.4%
• Uric acid-overproduction type in the classification of hyperuricemia
• History of, clinically significant cardiac, hematologic and hepatic disease
• Kidney calculi or clinically significant urinary calculi
• eGFR: < 30mL/min/1.73m^2
• Systolic blood pressure: >= 180 mmHg
• Diastolic blood pressure: >= 110 mmHg