Ambrisentan Data to Be Presented at World Congress of Cardiology 2006

Business Wire, Sept 5, 2006

DENVER -- 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 an abstract describing the effects of ambrisentan in patients with pulmonary arterial hypertension (PAH) has been selected for presentation at the World Congress of Cardiology 2006, a joint meeting of the European Society of Cardiology and the World Heart Federation, to be held September 2-6, 2006 in Barcelona, Spain.

The abstract highlights efficacy and safety results from the ARIES-2 trial, a Phase 3 trial of ambrisentan in patients with PAH. The data demonstrate that ambrisentan improved exercise capacity and decreased levels of brain natriuretic peptide. Ambrisentan was well tolerated and was not associated with any clinically significant serum aminotransferase abnormalities, a marker of potential liver damage.

Nazzareno Galie, M.D., will present "Ambrisentan Improves 6-minute Walk Distance and Decreases Brain Natriuretic Peptide in Patients with Pulmonary Arterial Hypertension." This abstract will be presented at the abstract session, "Medical and Surgical Treatments for Pulmonary Hypertension," Wednesday, September 6, 2006, at 8:45 a.m. Dr. Galie is Professor of Cardiology at the University of Bologna and a principal investigator for ARIES-2.

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(R) (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 summary statements relating to the results of the Company's ARIES clinical trials. 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.

Results from clinical trials, including the Company's ARIES trials, are not necessarily predictive of future clinical results. Top line results may not be confirmed upon full analysis of the detailed results of a trial and additional information relating to the safety, efficacy or tolerability of the Company's product candidates, including ambrisentan, may be discovered upon further analysis of trial data and upon review and analysis of additional trial data. If the Company's product candidates do not meet 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 the Company's product candidates meet safety and efficacy endpoints, regulatory authorities may not approve them, the Company may not be able to successfully market them, or the Company may face post-approval problems that require the withdrawal of its product from the market. The Company's results may be affected by its effectiveness at managing its financial resources, its ability to successfully develop and market its product candidates, its ability to obtain and enforce patent protection for its products, competition from other biotechnology and pharmaceutical companies, difficulties or delays in manufacturing its products, and regulatory developments involving current and future products. Delays in initiating or conducting clinical trials, whether caused by competition, adverse events, patient enrollment rates, regulatory issues or other factors, could adversely affect the Company's financial position and prospects. 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. Myogen may not ever have any products that generate significant revenue.

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 reports on Form 10-Q and Form 8-K. It is Myogen's policy to only update or reconfirm its public guidance by issuing a press release or filing a periodic or current report with the Securities and Exchange Commission. All information in this press release is as of September 5, 2006. Myogen undertakes no duty or obligation to update any forward-looking statements contained in this release as a result of new information, future events or changes in the Company's expectations.