Nuvelo Inc. has started enrolment in a Phase 3 trial evaluating the efficacy of its lead product candidate, alfimeprase, for the treatment of central venous catheter occlusion (CO).

Alfimeprase, an enzyme produced by recombinant DNA technology, possesses a unique mechanism of action. It directly degrades fibrin, producing a rapid dissolution of blood clots. Alfimeprase is currently being evaluated in a Phase 3 clinical program for the treatment of patients with acute peripheral arterial occlusion (PAO), also known as "leg attack."

Known as SONOMA-2 (Speedy Opening of Non-Functional and Occluded Catheters with Mini-Dose Alfimeprase), the Phase 3 trial is one of two overlapping, multi-national trials in Nuvelo's Phase 3 alfimeprase program for catheter occlusion. The randomized, double-blind study compares the efficacy of 3 mg of alfimeprase with placebo in 300 patients with occluded central venous catheters. Two-thirds of the participants will receive alfimeprase and the remainder will receive placebo. The primary endpoint of the study is restoration of catheter function within 15 minutes. The second study in the Phase 3 program, called SONOMA-3, is an open-label, single-arm trial evaluating the safety and efficacy of alfimeprase in 800 patients.

Previously announced results from a Phase 2 study demonstrated that alfimeprase restored flow to 40% and 50% of occluded catheters 5 and 15 minutes after the first dose, respectively. By comparison, Cathflo Activase, the only treatment currently approved in the US for resolution of occluded catheters, did not restore flow at either time point. In addition, alfimeprase restored flow to 60% of occluded catheters at 120 minutes after the first dose and to 80% of occluded catheters at 120 minutes after the second dose compared with 46% at 120 minutes after the first dose and 62% at 120 minutes after the second dose with Cathflo Activase.

Each year in the United States, approximately 5 million catheters are placed in patients to deliver chemotherapy, nutritional support, antibiotics and blood products.