Single and Multiple Dose Study in Japanese

While there is extensive clinical experience with lesinurad in the Western population, it is
recognized that both intrinsic and extrinsic factors may impact the PK, PD, safety, and dose
response in different ethnic populations. The purpose of this study is to explore the
safety, tolerability, pharmacokinetic (PK), and pharmacodynamic (PD) of single and multiple
doses of lesinurad in healthy Japanese males, and to allow comparison of these parameters
with the Western population.

Inclusion Criteria:

- Able to understand the study procedures, the risks involved and willing to provide
written Informed Consent before the first study related activity.

- Healthy adult subjects born in Japan

- All laboratory parameters should be within normal limits or considered not clinically
significant by the investigator.

- Screening serum uric acid level >= 4.5 mg/dL.

- Subjects must be free of any clinically significant disease that requires a
physician's care and/or would interfere with study evaluations or procedures.

- Subject does not have clinically relevant abnormalities in blood pressure, heart
rate, body temperature, and respiratory rate, as per the Investigator's judgment.

Exclusion Criteria:

- Positive serology to Human Immunodeficiency Virus (HIV-1 and HIV-2).

- Positive test for active Hepatitis B or Hepatitis C infection.

- History of kidney stones.

- Undergone major surgery within 3 months of Day 1.

- Subject has received the last dose of an investigational drug (or treatment with a
medical device) within 30 days or 5 half-lives (whichever is longer) of the
investigational drug prior to Day 1 or are currently participating in another study
of an investigational drug (or medical device).

- Prior exposure to lesinurad (RDEA594) or RDEA806.