PRESS RELEASE: Nuvelo Begins Phase 2 Trial and Receives Fast Track Status for Alfimeprase in Patients With Acute Ischemic Stroke

Nuvelo Begins Phase 2 Trial and Receives Fast Track Status for Alfimeprase in Patients With Acute Ischemic Stroke

SAN CARLOS, Calif., December 12, 2007 -- Nuvelo, Inc. today announced dosing of the first patient in a Phase 2 proof-of-concept trial of alfimeprase for the treatment of acute ischemic stroke.

Nuvelo has also been granted fast track designation by the U.S. Food and Drug Administration (FDA) for alfimeprase in this indication. Fast track designation, which was mandated by the FDA Modernization Act of 1997, can potentially facilitate expedited review of a Biologics License Application (BLA). Fast track designation is reserved for new drugs that demonstrate the potential to address an unmet medical need and are intended for the treatment of a serious or life-threatening condition.

The Phase 2 CARNEROS-1 (Catheter Directed Alfimeprase for Restoration of Neurologic Function and Rapid Opening of Arteries in Stroke) proof-of-concept trial is a multi-center, open-label, two part, dose escalation (1 mg, 5 mg and 10 mg) study that will enroll approximately 100 patients within 3-9 hours of stroke onset. CARNEROS-1 is designed to evaluate the safety and efficacy of intra-arterial, catheter-directed, bolus alfimeprase. The primary efficacy endpoint is recanalization, or unblocking, of the primary arterial occlusive lesion within 120 minutes of treatment with alfimeprase. Safety will be assessed, including the rate of symptomatic intracerebral hemorrhages at 24 hours.

"We believe that a safer, more efficacious intra-arterial therapy can change the treatment paradigm for stroke patients and that a product candidate such as alfimeprase holds the potential to restore flow rapidly and expand the current treatment window for this underserved patient population," said Michael Levy, M.D., executive vice president of research and development for Nuvelo.

With approximately 700,000 cases in the United States per year, stroke is the third leading cause of death and a leading cause of severe, long-term disability. Every 45 seconds someone has a stroke, and every three minutes someone dies of one. A stroke occurs when a blood vessel that carries oxygen and nutrients to the brain becomes blocked by a blood clot (ischemic stroke) or ruptures (hemorrhagic stroke). This interruption in the blood and oxygen supply, to part of the brain, results in cell death and loss of function.

"There is a need for new and more effective approaches to stroke therapy for patients who present more than three hours after onset of symptoms," said Dr. Lawrence Wechsler, professor of neurology and neurological surgery at the University of Pittsburgh Medical School and director of the University of Pittsburgh Medical Center Stroke Institute. "Alfimeprase could be well suited for this particular setting as it is a clot-dissolver that holds the potential to directly and rapidly dissolve blood clots while keeping its activity localized to the site of delivery. We look forward to conducting this proof-of-concept trial to determine if alfimeprase's unique attributes translate into positive study outcomes for this patient population."

About Alfimeprase

Alfimeprase is a recombinant direct acting fibrinolytic (rDAF) that has the potential to rapidly dissolve blood clots through a unique mechanism of action -- it directly degrades fibrin, a protein that provides the scaffolding for blood clots. In addition, alfimeprase's thrombolytic activity appears to be localized to the site of delivery because it is rapidly inactivated by alpha-2 macroglobulin, a naturally occurring protein in the blood, as it moves away from the site of delivery and into the general blood circulation.

In addition to acute ischemic stroke, alfimeprase is also being evaluated as a potential treatment for catheter occlusion.

About Nuvelo

Nuvelo, Inc. is dedicated to improving the lives of patients through the discovery, development and commercialization of novel drugs for acute cardiovascular disease, cancer and other debilitating medical conditions. Nuvelo's development pipeline includes alfimeprase, a direct acting fibrinolytic in Phase 2 clinical development for the treatment of thrombotic-related disorders including acute ischemic stroke and catheter occlusion; and preclinical candidates NU206 for the potential treatment of chemotherapy/radiation therapy-induced mucositis and inflammatory bowel disease and NU172, a direct thrombin inhibitor for use as a potential short-acting anticoagulant during medical or surgical procedures. In addition, Nuvelo expects to continue its research programs in leukemia therapeutic antibodies and Wnt signaling pathway therapeutics to further expand its pipeline and create additional partnering and licensing opportunities.

Information about Nuvelo is available at our website at http://www.nuvelo.com or by phoning 650-517-8000.

This press release contains "forward-looking statements," which include statements regarding potential use of alfimeprase as a treatment for stroke, the timing and progress of Nuvelo's clinical stage and research programs, and the potential benefits that patients may experience from the use of our clinical stage compounds, which statements are hereby identified as "forward-looking statements" for purposes of the safe harbor provided by the Private Securities Litigation Reform Act of 1995. Such statements are based on our management's current expectations and involve risks and uncertainties. Actual results and performance could differ materially from those projected in the forward-looking statements as a result of many factors, including, without limitation, uncertainties relating to drug discovery; clinical development processes; enrollment rates for patients in our clinical trials; changes in relationships with strategic partners and dependence upon strategic partners for the performance of critical activities under collaborative agreements; stock market conditions; the impact of competitive products and technological changes; and uncertainties relating to our ability to obtain funding. These and other factors are identified and described in more detail in Nuvelo's filings with the SEC, including without limitation Nuvelo's quarterly report on Form 10Q for the quarter ended September 30, 2007 and subsequent filings. We disclaim any intent or obligation to update these forward-looking statements.