DORADO-EX - A Dose-Blinded, Long-Term Safety Extension Study of Fixed Doses of Darusentan in Subjects With Resistant Systolic Hypertension Receiving Combination Therapy With Three or More Antihypertensive Drugs, Including a Diuretic (Protocol DAR-311-E)

This is a research study of a new experimental drug called darusentan. Darusentan is not currently approved by the United States (U.S.) Food and Drug Administration (FDA) for use in the U.S., which means that a doctor cannot prescribe this drug. The purpose of this study is to evaluate the long-term safety of darusentan in subjects with resistant systolic hypertension despite treatment with full doses of three or more antihypertensive medications, including a diuretic.