Open-Label Lesinurad Monotherapy Extension Study in Gout

This is a Phase 3, open-label, uncontrolled, extension study to assess the long-term
efficacy and safety of lesinurad monotherapy in subjects who completed the double-blind
treatment period in Study RDEA594-303.

Inclusion Criteria:

- Subject is able to understand the study procedures and the risks involved and is
willing to provide written informed consent before the first study related activity.

- Subject completed the double-blind treatment period in Study RDEA594-303 and was
actively receiving and tolerating study medication (lesinurad or placebo) at Month 6
visit.

- Subject is willing to adhere to the visit/protocol schedules.

- Subject is male or female; female subjects of childbearing potential must agree to
use an effective non-hormonal method of birth control during the study and for at
least 14 days after the last dose of study medication.

Exclusion Criteria:

- Subject has any other medical or psychological condition, which in the opinion of the
Investigator and/or the Medical Monitor, might create undue risk to the subject or
interfere with the subject's ability to comply with the protocol requirements or to
complete the study.