Myogen, Inc., a biopharmaceutical company focused on the discovery, development and commercialization of small molecule therapeutics for the treatment of cardiovascular disorders, announced that Lewis Rubin, will present detailed results of AMB-220, the phase II study of ambrisentan in pulmonary arterial hypertension (PAH), at the ATS 2004 International Conference. Myogen previously disclosed summary results of the study in 2003. Dr Rubin's abstract has been selected for an oral presentation at a mini-symposium, Emerging Therapies for PAH, May 23, 2004. Dr Rubin is director of the Pulmonary Vascular Center at the University of California, San Diego School of Medicine and a principal investigator for AMB-220.

ATS 2004, the 100th International Conference of the American Thoracic Society will be held May 21 - 26, 2004 at the Orange County Convention Center in Orlando, Florida.

Myogen completed AMB-220 in September 2003. The study was a randomized, double-blind, multi-center, dose-ranging phase II study evaluating the effect of ambrisentan on exercise capacity of patients with moderate to severe PAH. Exercise capacity was the primary efficacy endpoint and was measured as the change from baseline in the six-minute walk test distance after 12 weeks of treatment.

In January 2004, Myogen announced that it began patient enrollment in ARIES I & II, the pivotal phase III clinical trials of ambrisentan for the treatment of PAH.