Nuvelo, Inc. (Nasdaq: NUVO) announced positive results from the Phase 1 proof-of-concept trial (n=30) of NU172, demonstrating that the thrombin-inhibitor achieved rapid onset and offset of anticoagulation after a single bolus dose with a favorable safety profile.

"There is a significant need for anticoagulants with fewer side effects and more predictable dosing than treatments currently available today," said David J. Schneider, M.D., professor of medicine and director of cardiology and vascular biology at the University of Vermont. "NU172 represents a new approach to anticoagulation for medical and surgical procedures through its potential to produce rapid and predictable onset of anticoagulation followed by rapid reversal once the infusion is discontinued."

The single-center, Phase 1 trial examined the safety, tolerability and pharmacokinetics of escalating bolus doses of NU172 in normal, healthy volunteers. In the trial, NU172 produced dose-dependent increases in anticoagulation, measured by activated clotting time (ACT). The 2.00 mg/kg bolus dose of NU172 achieved target ACTs of approximately 400 seconds. Upon withdrawal of NU172 the ACT showed a rapid return toward baseline with a plasma half-life of NU172 of approximately 10 minutes. No serious adverse events occurred in the trial.

"We are very encouraged by these findings and NU172's potential to address the need for rapid onset and offset of anticoagulation in medical procedures such as coronary artery bypass graft surgery and percutaneous coronary intervention," said Dr. Ted W. Love, chairman and chief executive officer of Nuvelo. "We plan to launch a Phase 1b trial of bolus dosing followed by escalating infusion doses of NU172 later this quarter, which should enable us to quickly begin a Phase 2 study evaluating NU172 in medical or surgical procedures in the fourth quarter of 2008 or the first quarter of 2009."

According to the American Heart Association, more than 450,000 coronary artery bypass graft (CABG) procedures and more than 1.2 million percutaneous coronary interventions (PCIs) are performed annually in the United States. Heparin, which must be paired with its antitode protamine for reversal, is the current standard of care for anticoagulation in CABG surgeries and PCI.

About Aptamers and NU172

Aptamers are chemically synthesized single-stranded nucleic acids that form well-defined three-dimensional shapes, allowing them to bind target molecules in a manner that is conceptually similar to antibodies. Characteristics of aptamers include high specificity and affinity, and the ability to target protein-protein interactions.

NU172 is an aptamer designed to directly inhibit thrombin's ability to stimulate blood clot formation in the setting of medical procedures where human blood is exposed to foreign materials. Specifically, NU172 is being studied for use as a potential short-acting anticoagulant during procedures such as coronary artery bypass graft surgery and percutaneous interventions. Data from the Phase 1 trial and preclinical studies suggest that NU172 has the potential for predictable anticoagulant effects, rapid onset and offset of action, and avoidance of thrombocytopenia.

About Nuvelo and Archemix's Joint Collaborative Effort

In August 2006, Nuvelo expanded its collaboration with Archemix to develop and commercialize aptamers that have a short-acting anticoagulant effect. Under the agreement, Archemix is responsible for discovery of short-acting aptamers for use in medical procedures, and Nuvelo leads development and worldwide commercialization of these aptamers.

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 NU172, a direct thrombin inhibitor in Phase 1 development for use as a potential short-acting anticoagulant during medical or surgical procedures; and preclinical candidate NU206, a Wnt pathway modulator for the potential treatment of chemotherapy/radiation therapy-induced mucositis and inflammatory bowel disease. In addition, Nuvelo is pursuing research programs in leukemia and lymphoma therapeutic antibodies and Wnt signaling pathway therapeutics to further expand its pipeline and create additional partnering and licensing opportunities.

This press release contains "forward-looking statements," which include statements regarding the timing, progress and anticipated completion of Nuvelo's clinical stage and research programs, the anticipated availability of top-line data, projected operating expenses and cash usage 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 and the regulatory approval process; 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; and the impact of competitive products and technological changes. These and other factors are identified and described in more detail in Nuvelo's filings with the SEC, including without limitation Nuvelo's annual report on Form 10-K for the year ended December 31, 2007 and subsequent filings. We disclaim any intent or obligation to update these forward-looking statements.

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