Myogen reports positive ambrisentan data

US biopharmaceutical firm Myogen has announced the results of two pivotal Phase III trials evaluating ambrisentan, an oral endothelin receptor antagonist, as a treatment for pulmonary arterial hypertension. Analysis of data derived from the AIRES 1 and 2 studies showed that the drug conferred a robust and dose-dependant increase in the exercise capacity of subjects receiving it. Moreover, the firm added that the increase reached levels of statistical-significance at all doses and that the drug significantly increased the time to disease progression, the assessment's secondary endpoint.

The firm went on to say that its preliminary analysis of the safety data suggested that the drug was well-tolerated, with the most frequently observed adverse event being mild-moderate peripheral edema. Additionally, the data showed that no patients treated with ambrisentan developed serum aminotransferase concentrations greater than three-times the upper limit of the normal range during the 12-week assessment. Approximately 400 of the study subjects are participating in longer-term trials of the drug.