Bayer HealthCare and Nuvelo begin second pivotal phase III trial of lead product candidate, alfimeprase

Treatment of central venous catheter occlusion

Monday - February 27, 2006, Leverkusen, Germany / San Carlos, Calif., U.S. – Bayer HealthCare (BHC) and Nuvelo Inc. (Nasdaq: NUVO) today announced that they have begun patient enrollment in a second pivotal phase III clinical trial of lead product candidate, alfimeprase, for the treatment of central venous catheter occlusion (CO). Alfimeprase is a novel thrombolytic or blood clot dissolver.

The phase III trial, known as SONOMA-3 (Speedy Opening of Non-functional and Occluded catheters with Mini-dose Alfimeprase-3), is the second of two overlapping, multi-national trials in the phase III alfimeprase program for CO. This open-label, single-arm trial will evaluate the safety and efficacy of 3 mg of alfimeprase in 800 patients with occluded central venous catheters.

In January 2006 Bayer HealthCare AG (BHC) and Nuvelo Inc. announced that they entered into a collaboration agreement for the global development and commercialization of alfimeprase. Under the terms of the agreement, Bayer will commercialize alfimeprase in all territories outside the United States.

“We believe that alfimeprase has the potential to quickly dissolve clots and rapidly restore the ability to infuse critical therapy such as chemotherapy or antibiotics through once occluded catheters,” said Steven R. Deitcher, M.D., vice president of medical sciences for Nuvelo and former principal investigator of the phase II trial. “We look forward to completing the first trial in this program, SONOMA-2, later this year and expect the phase III trial results to confirm the ability of alfimeprase to restore function to occluded catheters in 15 minutes or less, as demonstrated in our phase II trial.”

Previously announced results from a phase II multi-center, randomized, double-blind study in 55 patients with occluded central venous catheters demonstrated that alfimeprase restored flow to 40 percent and 50 percent of occluded catheters 5 and 15 minutes after the first dose, respectively. By comparison, Cathflo®Activase® (alteplase) did not restore flow at either time point. Alfimeprase also restored flow to 60 percent of occluded catheters at 120 minutes after the first dose and to 80 percent of occluded catheters at 120 minutes after the second dose compared with 46 percent at 120 minutes after the first dose and 62 percent at 120 minutes after the second dose with Cathflo®Activase®.

About Catheter Occlusion
Delivery of chemotherapy, nutritional support, antibiotics and blood products, as well as the frequent withdrawal of blood samples for laboratory testing, are often facilitated via central venous catheters. Approximately 5 million catheters are placed in patients in the United States each year, with as many as 25 percent becoming occluded. When a catheter becomes occluded, the goal is to restore flow in a prompt and cost-effective manner with minimal risk to the patient. As these catheters are primarily inserted in patients receiving life-saving medications such as chemotherapy, it is critical to restore flow through the catheter as soon as possible. In the case of thrombotic occlusions, treatment with thrombolytic drugs represents a less-invasive and more cost-effective alternative to replacement. Currently, Cathflo®Activase® is approved in the United States for restoring function to central venous catheters.

Additional Clinical Trials
The first study in the ongoing phase III clinical program in CO, SONOMA-2, began in September 2005 and is expected to complete enrollment in the second half of this year. This randomized, double-blind study is comparing the efficacy of 3 mg of alfimeprase with placebo in 300 patients with occluded central venous catheters. Two-thirds of the participants are receiving alfimeprase and the remainder are receiving placebo. The primary endpoint is restoration of catheter function within 15 minutes.

Alfimeprase is also being studied in an ongoing phase III program known as the NAPA (Novel Arterial Perfusion with alfimeprase) program, for the treatment of acute peripheral arterial occlusion (PAO), or “leg attack.” The program consists of two overlapping, randomized, double-blind, multi-national trials comparing 0.3 mg/kg of alfimeprase with placebo in a total of 600 patients. The primary endpoint in both trials is avoidance of open vascular surgery within 30 days of treatment. A variety of secondary endpoints are also being evaluated, including safety endpoints such as the incidence of bleeding, and pharmacoeconomic endpoints such as length of hospital and intensive care unit (ICU) stay. The first trial in this program, NAPA-2, is expected to complete enrollment in the second half of this year. The second trial, NAPA-3, is expected to begin in early 2006 and is being conducted under a special protocol assessment from the FDA.

In January 2006, Nuvelo received fast track designation from the U.S. Food and Drug Administration (FDA) for the NAPA program. 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.

In addition, Nuvelo recently announced plans to initiate a phase II trial of alfimeprase for the treatment of ischemic stroke in the second half of 2006, and a phase II trial of alfimeprase for the treatment of deep venous thrombosis in 2007.

About Bayer HealthCare AG
Bayer HealthCare AG, a subsidiary of Bayer AG, is one of the world’s leading, innovative companies in the health care and medical products industry. In 2004, the Bayer HealthCare subgroup generated sales amounting to some 8.5 billion Euro.

The company combines the global activities of the divisions Animal Health, Consumer Care, Diabetes Care, Diagnostics and Pharmaceuticals. Since January 1, 2006 the new Pharmaceutical Division consists of the former Biological Products and Pharmaceutical Division and now comprises three business units: Hematology/Cardiology; Oncology and Primary Care.
Bayer HealthCare employed 35,300 people worldwide in 2004.

Bayer HealthCare’s aim is to discover and manufacture innovative products that will improve human and animal health worldwide. The products enhance well-being and quality of life by diagnosing, preventing and treating disease.


Forward-looking statements
This news release contains forward-looking statements based on current assumptions and forecasts made by Bayer Group management. Various known and unknown risks, uncertainties and other factors could lead to material differences between the actual future results, financial situation, development or performance of the company and the estimates given here. These factors include those discussed in our public reports filed with the Frankfurt Stock Exchange and with the U.S. Securities and Exchange Commission (including our Form 20-F).The company assumes no liability whatsoever to update these forward-looking statements or to conform them to future events or developments.

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Christina Sehnert

Head of Coporate Policy Research and Development

Bayer HealthCare AG

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