The purpose of this study is exploratory investigation of safety and efficacy (dose response and optimal dose according to the percent reduction from baseline in serum urate level at the final visit) of FYU-981 administered orally to hyperuricemic patients with and without gout for 8 weeks (dose-escalating initial period: 4 weeks followed by maintenance period: 4 weeks) by the method of randomized (dynamic allocation), placebo-controlled, double-blind, parallel group comparison.

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: < 60mL/min/1.73m^2
• Systolic blood pressure: >= 180 mmHg
• Diastolic blood pressure: >= 110 mmHg