Primary Pulmonary Hypertension News - Menu Ambrisentan PAH Long-Term Safety and Efficacy Data Presented at ATS 2005 San Diego DENVER, May 23 /PRNewswire-FirstCall/ -- Myogen, Inc. (Nasdaq: MYOG - News), a biopharmaceutical company focused on the discovery, development and commercialization of small molecule therapeutics for the treatment of cardiovascular disorders, today announced that two abstracts describing the effects of ambrisentan in patients with pulmonary arterial hypertension (PAH) were presented at ATS 2005 - San Diego, the annual International Conference of the American Thoracic Society. These abstracts summarize additional results from the Phase 2 study of ambrisentan in 64 patients with PAH (AMB-220) and the subsequent open-label long-term study (AMB-220-E). One-year follow-up safety and efficacy results, as well as comparable effects of ambrisentan in WHO functional Class II and Class III PAH patients, were presented. The data showed that both patient populations benefited equally in their improvement in six-minute walk distance at 12 weeks (37.7 meters for patients with Class II symptoms and 35.2 meters for patients with Class III symptoms) and at 24 weeks (58.3 meters for patients with Class II symptoms and 51.9 meters for patients with Class III symptoms). There were no statistically significant differences between the two groups in the change from baseline at either time point. Improvements in six-minute walk distance at week 12 and week 24 were accompanied with sustained or improved levels of dyspnea (or breathlessness) compared to baseline for both classes. Class III patients had a significant improvement from baseline in dyspnea following exercise at week 12 and week 24, while Class II patients maintained a similar level of dyspnea compared to baseline, even though they were walking substantially further in the six-minute walk test. The improvements in Borg dyspnea index between the two groups were significantly greater for the Class III patients at week 24, but not at week 12. On Monday, Nazzareno Galie, M.D., presented "Ambrisentan Long-Term Safety and Efficacy in Pulmonary Arterial Hypertension One Year Follow-Up." Dr. Galie is Professor of Cardiology at the University of Bologna and a principal investigator for AMB-220. The one-year data demonstrate that ambrisentan produced a significant and durable benefit on exercise capacity and other clinical measures of PAH. These data also indicated a survival benefit to patients treated with ambrisentan when compared to predicted survival based on the National Institutes of Health Registry formula. Dr. Galie reported the Phase 2 safety and efficacy results for the first year of ambrisentan therapy. Fifty-four of the original 64 patients enrolled in the open-label long-term study, the majority of whom are still receiving ambrisentan monotherapy today, all with a minimum exposure of at least 2 years. The 48-week analysis reported by Dr. Galie was for all 64 patients, including patients who discontinued therapy prior to week 48. The mean dose for these patients was 7.5 mg of ambrisentan once daily, with all patients being maintained on ambrisentan monotherapy. At week 48, the mean improvement from baseline in six-minute walk distance was 54.5 meters; similar to what was observed at week 24 (54.2 meters) and significantly better than the improvement observed at week 12 (36.1 meters). There was also a significant and durable benefit observed in the Borg dyspnea index after exercise, similar to improvement seen at weeks 12 and 24. During the 48-week period, 57% of patients experienced an improvement in WHO functional class, while only 5% had a worsening of functional status. This resulted in 59% of patients being assessed as WHO Class I or II at Week 48; 11% of which were WHO Class I, or asymptomatic. The remainder of the patients were WHO Class III. No patients worsened to Class IV. Also of note, the one-year survival observed for 39 patients with idiopathic PAH was 92% compared to an NIH registry predicted survival of 74%. One-year survival of the patients with secondary PAH was 95%, although there is no NIH registry against which to benchmark these results. The adverse events in these patients observed over the entire 48 weeks of treatment were comparable to that reported for the first 12 weeks of treatment, with the majority of the events occurring in the first 12 weeks. No additional elevations in AST and/or ALT >3xULN were observed during the first year. There were no alterations in prothrombin time, international normalized ratio (INR) or warfarin dose. Myogen completed "AMB-220 - A Phase II, Randomized, Double-Blind, Dose-Controlled, Dose-Ranging, Multicenter Study of Ambrisentan Evaluating Exercise Capacity in Patients with Moderate to Severe Pulmonary Arterial Hypertension" in September 2003 and the initial study results were presented at ATS 2004 - Orlando in May 2004. This study demonstrated a statistically significant increase in the primary efficacy endpoint, change from baseline in the 6-minute walk distance after 12 weeks of treatment, for all dose groups evaluated. Clinically meaningful improvements were observed in several secondary endpoints, including dyspnea (breathlessness) score, WHO functional class and cardiopulmonary hemodynamics. The subsequent long-term study titled, "AMB-220-E - An Open-Label, Long-term Study of Ambrisentan in Pulmonary Hypertension Subjects Having Completed Myogen Study AMB-220," remains ongoing with a mean ambrisentan exposure of two years. Conference Call J. William Freytag, President and CEO, and other members of Myogen's senior management will discuss the data presentations via webcast and conference call on Tuesday, May 24, 2005 at 9:00 am Eastern. To access the live webcast, please log on to the company's website at www.myogen.com and go to the Investor Relations section. Alternatively, callers may participate in the conference call by dialing 800-240-6709 (domestic) or 303-262-2130 (international). Webcast and telephone replays of the conference call will be available approximately two hours after the completion of the call through Friday, June 3, 2005. Callers can access the replay by dialing 800-405-2236 (domestic) or 303-590-3000 (international). The passcode is 11031385#. About Myogen Myogen is a biopharmaceutical company focused on the discovery, development and commercialization of small molecule therapeutics for the treatment of cardiovascular disorders. Myogen currently markets one product in Europe for the treatment of acute decompensated heart failure and has three product candidates in late-stage clinical development: enoximone capsules for the treatment of patients with advanced chronic heart failure, ambrisentan for the treatment of patients with pulmonary arterial hypertension and darusentan for the treatment of patients with resistant hypertension. The company, in collaboration with Novartis, 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 the statements relating to the Company's ambrisentan clinical data. Actual results could differ materially from those projected and Myogen cautions investors not to place undue reliance on the forward-looking statements contained in this release. The results of Myogen's prior clinical trials of its product candidates, including ambrisentan, do not necessarily predict the results of later-stage clinical trials, including the results of the Company's current ARIES-1 & ARIES-2 clinical trials. Results of the Company's current and former ambrisentan clinical trials 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, darusentan, and enoximone, 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. Myogen is at an early stage of development and 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, 2004 and Myogen's periodic reports on Form 10-Q and Form 8-K. Myogen is providing the information contained in this release as of the date of the release and does not undertake any obligation to update any forward-looking statements as a result of new information, future events or otherwise. -------------------------------------------
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