There are about 8 million people in the U.S. with gout, characterized by high uric acid levels, which lead to painful crystal deposits in joints. About half of those are seeking treatment, mostly with allopurinol, which is available as a generic, but about half of those are unable to reach the target of 6 mg/dl of uric acid, the level at which uric acid becomes insoluble, forming crystals which cause about three to six flares per year.