alfimeprase

Alfimeprase is a recombinant, direct-acting fibrinolytic enzyme derived from fibrolase, a zinc metalloproteinase originally isolated from the venom of the southern copperhead snake (Agkistrodon contortrix contortrix)[1][5][6]. Developed using recombinant DNA technology, alfimeprase was designed to rapidly and directly degrade fibrin—the main protein component of blood clots—when delivered locally via catheter to the site of thrombosis[1][2][3]. Its mechanism is unique among thrombolytics in that it does not rely on plasminogen activation but instead cleaves fibrin(ogen) directly, primarily targeting the Aα chain[5][6]. Alfimeprase’s activity is highly localized because it is quickly neutralized by alpha-2 macroglobulin upon entering systemic circulation, reducing the risk of systemic bleeding complications seen with other thrombolytics[2][3][5]. The drug was developed for acute peripheral arterial occlusion (PAO), catheter occlusion (CO), and acute ischemic stroke. Despite promising early-phase results showing rapid clot dissolution and a favorable safety profile compared to traditional agents like tissue plasminogen activator, clinical development was discontinued after phase III trials failed to demonstrate significant benefit over placebo or standard care[1][7].