Alfimeprase Clears Peripheral Clots in Early Clinical Studies

By Jeff Evens

LONDON -- The novel fibrinolytic drug alfimeprase may have a quicker mechanism of action and better safety profile than current treatments for acute peripheral arterial occlusion, Dr. Gunnar Tepe said at the Charing Cross 28th International Symposium.

Existing treatments for acute thrombotic conditions such as peripheral arterial occlusion (PAO) have limitations. Plasminogen activators can cause bleeding complications in 5%-15% of patients and take up to 24 hours for delivery via a catheter, the efficacy of mechanical clot-removing devices is not well established, and open surgery can cause significant morbidity, said Dr. Tepe, the University of Tübingen (Germany).

Alfimeprase must be administered close to the thrombus via an intraarterial catheter. said Dr. Tepe, who has no conflicts of interest with Amgen Inc. and Nuvelo Inc., which would manufacture and market the drug.

In an open-label, multicenter phase I safety study of alfimeprase in 20 patients with worsening symptoms of lower extremity ischemia, no severe adverse events, including bleeding complications, occurred (J. Vasc. Interv. Radiol. 2005;16:1075-83).

An open-label, multicenter phase II trial tested alfimeprase in 113 patients with acute PAO. After 4 hours of treatment, blood flow was restored in up to 76% of patients who followed the trial's protocol and in up to 60% of patients in an intention-to-treat analysis. In each group, 52%-69% of patients avoided surgical intervention. There were no intracerebral hemorrhages, systemic bleeding events, or deaths.