Phase 2/3 Clinical Trial Results To Be Released the Week of 6th July

ARYx Therapeutics Inc. (NASDAQ:ARYX), a biopharmaceutical company, announced today that the database for the EmbraceAC study has been locked and the study remains on schedule, with the efficacy and safety results to be available during the week of July 6, 2009. The study was designed to compare its oral anticoagulation therapy, tecarfarin (previously ATI-5923), against the leading anticoagulant agent, warfarin. The purpose of the trial is to evaluate whether tecarfarin is superior to warfarin in its ability to maintain patients within a target therapeutic range of the level of anticoagulation as measured by INR (International Normalized Ratio). Based upon recent interactions with the U. S. Food and Drug Administration (FDA), ARYx believes this trial could be positioned as one of the required registration studies for tecarfarin.

The raw data, containing both the efficacy and safety results, will now be transferred to independent statisticians who will create the tables and listings according to the previously adopted statistical analysis plan. This plan has been reviewed by the FDA. The results from the study will remain blinded to ARYx until just prior to their public release.

The trial of approximately 600 patients is a randomized, double blind, parallel group, active control study comparing tecarfarin with warfarin in patients who require chronic, oral anticoagulation. All patients in the study were treated for a minimum of six months and required anticoagulation therapy to avoid serious blood clotting resulting from their underlying condition. This includes patients with atrial fibrillation; an implanted prosthetic heart valve; a history of venous thromboembolic disease; a history of myocardial infarction or cardiomyopathy; or another indication for which they are currently receiving chronic warfarin therapy. The same target therapeutic range of INR has been applied for patients receiving warfarin therapy as those administered tecarfarin.