Lesinurad Combos Nail Uric Acid Targets in Phase III Trials

August 21, 2014

Article

Unpublished results from Phase III trials of the uric acid inhibitor lesinurad offer promise of help for gout patients who have not reached treatment targets with allopurinol or febuxostat.

Newly announced results from Phase III trials point toward another option for gout patients unable to reach target serum uric acid (sUA) levels with optimal doses of allopurinol or febuxostat. The drug lesinurad, a selective uric acid reabsorption inhibitor that blocks the uric acid transporter URAT1, significantly increased the number of patients reaching the target sUA goals, in combination with either of the two standard gout treatments.

Phase III results for the CLEAR and CRYSTAL trials have been announced in a press release from the manufacturer, AstraZeneca. The company says it will submit them for presentation at a scientific conference later this year.

Patients received lesinurad at daily doses of 200 or 400 mg in combination with at least 300 mg of allopurinol daily (or at least 200 mg for those with kidney impairment) in the CLEAR trials, or with 80 mg daily of febuxostat in CRYSTAL.

With one exception (the lower dose in combination with febuxostat), reportedly all doses of lesinurad significantly (p<0.0001) boosted the proportion of patients achieving sUA targets by six months, compared to monotherapy with the older drug .

Will this solve the problem that over 50% of gout patients don't reach treatment goals? There's no question that the unmet need is "huge," but it's not clear how much to blame poor adherence or suboptimal dosing of existing drugs, remarked gout specialist Theodore R. Fields MD, Professor of Clinical Medicine at Weill Cornell Medical College, in a telephone conversation,

However, he predicted that, if the drug is approved, rheumatologists "may well consider" adding it for patients who aren't reaching target sUA levels despite their best efforts.

One issue worth watching, Fields added, is that kidney stones developed in some patients at the 400 mg dose of lesinurad. It will be of great interest, he added, to see how the study evaluated kidney stone risk of study patients prior to starting lesinurad, noting "that's data we'll really want to see in detail."