Combination Treatment Study in Subjects With Tophaceous Gout With Lesinurad and Febuxostat

Inclusion Criteria: * Subject is able to understand the study procedures, the risks involved and willing to provide written informed consent before the first study related activity. * Subject is willing to adhere to the visit/protocol schedules. * Subject meets the diagnosis of gout as per the American Rheumatism Association * Criteria for the Classification of Acute Arthritis of Primary Gout. * Subject meets one of the following criteria: * Subjects who are not currently taking an approved ULT must have an sUA value of ≥ 8 mg/dL (476 µmol/L). * Subjects entering the study on a medically appropriate dose of febuxostat or allopurinol must have an sUA value of ≥ 6.0 mg/dL (357 µmol/L). * Subject must be able to take gout flare prophylaxis with colchicine or non-steroidal anti-inflammatory drug (NSAID) (including Cox-2 selective NSAID) ± PPI. * Subject with at least 1 measurable tophus on the hands/wrists and/or feet/ankles ≥ 5 mm and ≤ 20 mm in the longest diameter. * Body mass index (BMI) \< 45 kg/m2 Exclusion Criteria: * Subject with known hypersensitivity or allergy to febuxostat. * Subject who is taking any approved urate-lowering medication other than allopurinol or febuxostat that is indicated for the treatment of gout within 8 weeks of the Screening Visit. * Subject who previously received pegloticase. * Subject who consumes more than 14 drinks of alcohol per week (eg, 1 drink = 5 oz \[150 mL\] of wine, 12 oz \[360 mL\] of beer, or 1.5 oz \[45 mL\] of hard liquor). * …