June 17, 2008

ARYx Initiates Enrollment in Phase II/III Anticoagulation Trial

ARYx Therapeutics has started enrollment in a Phase II/III clinical trial comparing its oral anticoagulation therapy, ATI-5923, against the leading anticoagulant agent, warfarin.

The purpose of the trial, named EmbraceAC, is to evaluate whether ATI-5923 is superior to warfarin in its ability to maintain patients within a target therapeutic range of the level of anticoagulation.

The primary endpoint of the trial is to demonstrate that patients are maintained within the target INR range a higher percentage of the time when treated with ATI-5923 than with warfarin.

The trial is expected to enroll approximately 600 patients at over fifty clinical study sites in the US. It is a randomized, double-blind, parallel group, active control study comparing ATI-5923 with warfarin in patients who require chronic, oral anticoagulation. The patients will be treated for a minimum of six months.

Based upon recent interactions with the FDA, ARYx Therapeutics believes this trial could be positioned as one of the required registration studies for ATI-5923. Results will be announced at the end of the second quarter of 2009.