Zibotentan, an Endothelin Receptor Antagonist, Patients With Intermittent Claudication

Peripheral artery disease (PAD) is a major complication of atherosclerosis when blockages in the arteries to leg reduce blood flow and one of the resulting problems is termed intermittent claudication (IC). IC is leg pain with walking that is relieved with rest and IC is the most frequent clinical manifestation of PAD and it effects millions of Americans. The number of patients with, and the health care costs of, PAD will increase as the prevalence of PAD is associated with advancing age, diabetes, and smoking. Zibotentan (ZD4054) is an endothelin receptor A (ETA) blocker that undergone extensive human testing and has been shown to be safe in several patient population. There is ample evidence to suggest that an ETA blocker could improve blood flow to the legs in patients with PAD. In a study that will be funded by the National Institute of Health, the investigators will test the ability of this medication to allow better blood flow to the legs of patients with PAD. In patients with IC, the investigators will test the ability of ZD4054 to improve leg blood flow using a non-invasive imaging technique. In parallel the study will test for the ability of patients with leg pain to walk further and feel better.