Four Ambrisentan Studies to Be Presented at Chest 2006 -- Salt Lake City

DENVER--(BUSINESS WIRE)--Myogen, Inc. (Nasdaq: MYOG), a biopharmaceutical company focused on the discovery, development and commercialization of small molecule therapeutics for the treatment of cardiovascular disorders, today announced that four abstracts describing the effects of ambrisentan in patients with pulmonary arterial hypertension (PAH) and healthy volunteers have been selected for presentation at CHEST 2006, the scientific assembly of the American College of Chest Physicians (ACCP), to be held Oct. 21-26, 2006, at the Salt Palace Convention Center in Salt Lake City, Utah. Myogen expects to submit the ambrisentan New Drug Application to the U.S. Food and Drug Administration (FDA) in the fourth quarter of 2006.

“Ambrisentan Has No Clinically Relevant Effect on the Pharmacokinetics or Pharmacodynamics of Warfarin.”

Ronald Oudiz, M.D., will present “ARIES-1: A Placebo-Controlled, Efficacy and Safety Study of Ambrisentan in Patients with Pulmonary Arterial Hypertension.” This abstract has been selected for publication in CHEST and for oral presentation at a session titled “Pulmonary Vascular: Pulmonary Hypertension,” Convention Center 255 D, on Tuesday, Oct. 24, 2006, from 10:30 a.m. to 12 p.m. (Mountain). Dr. Oudiz is Director of Pulmonary Hypertension, Associate Professor, Department of Medicine, Division of Cardiology, Harbor-UCLA Medical Center, and was a principal investigator for the ARIES-1 study.

Three additional abstracts have been selected for publication in CHEST and for poster presentations on Wednesday, Oct. 25, 2006, from 12:30 p.m. to 2 p.m. (Mountain), in the Exhibit Hall.

Michael McGoon, M.D., will present “Ambrisentan Rescue Therapy in Patients with Pulmonary Arterial Hypertension Who Discontinued Bosentan or Sitaxsentan Due to Liver Function Abnormalities.” The results of this study and long-term follow-up will be presented. Dr. McGoon is Professor of Medicine, Mayo Clinic College of Medicine, and is a principal investigator for this AMB-222 study.

Michael Gerber, M.D., will present “Ambrisentan Has No Clinically Relevant Effect on the Pharmacokinetics or Pharmacodynamics of Warfarin.” Dr. Gerber is Senior Vice President of Clinical Development and Regulatory Affairs at Myogen.

Christopher Dufton, Ph.D., will present “Ambrisentan Has No Clinically Relevant Pharmacokinetic Interaction Between Ambrisentan and Sildenafil.” Dr. Dufton is Associate Director of Clinical Science at Myogen.

About Myogen

Myogen has two product candidates in late-stage clinical development: ambrisentan for the treatment of patients with pulmonary arterial hypertension (PAH) and darusentan for the treatment of patients with resistant hypertension. Myogen and GlaxoSmithKline have entered into a global PAH collaboration in which Myogen has marketing and distribution rights to GlaxoSmithKline's Flolan® (epoprostenol sodium) for Injection in the United States and GlaxoSmithKline has licensed ambrisentan from Myogen for all territories outside of the United States, where Myogen retains exclusive rights. Myogen also conducts a target and drug discovery research program focused on the development of disease-modifying drugs for the treatment of chronic heart failure and related cardiovascular disorders. Please visit Myogen's website at www.myogen.com.

Safe Harbor Statement

This press release contains forward-looking statements that involve significant risks and uncertainties, including statements relating to ambrisentan clinical data and expected timing of submission of the ambrisentan NDA. Actual results could differ materially from those projected and the Company cautions investors not to place undue reliance on the forward-looking statements contained in this release.

Among other things, the results of Myogen's prior clinical trials of its product candidates, including ambrisentan, do not necessarily predict the results of future clinical trials. Preliminary results may not be confirmed upon full analysis of the detailed results of a trial. There can be no assurance that Myogen's product candidates, including ambrisentan, have better safety profiles than competing products, including a lower incidence of liver toxicity or liver toxicity that is not dose dependent. Among other things, Myogen's results may be affected by competition from other pharmaceutical and biotechnology companies, Myogen's ability to successfully develop and market its current products, difficulties or delays in its clinical trials, regulatory developments involving current and future products and its effectiveness at managing its financial resources. If the Company's product candidates, including ambrisentan and darusentan do not meet the safety or efficacy endpoints in clinical evaluations, they will not receive regulatory approval and the Company will not be able to market them. Even if Myogen's product candidates meet safety and efficacy endpoints, regulatory authorities may not approve them, or the Company may face post-approval problems that require the withdrawal of its products from the market. If the Company is unable to raise additional capital when required or on acceptable terms, it may have to significantly delay, scale back or discontinue one or more of its drug development or discovery research programs.

Additional risks and uncertainties relating to the company and its business can be found in the "Risk Factors" section of Myogen's Form 10-K for the year ended December 31, 2005, and Myogen's periodic reports on Form 10-Q and Form 8-K. Myogen does not undertake any obligation to update any forward-looking statements contained in the anticipated presentation as a result of new information, future events or otherwise. The company cautions investors not to place undue reliance on the forward-looking statements contained in this press release or the presentation. No forward-looking statement can be guaranteed and actual events and results may differ materially from those projected.