December 09, 2003
Bayer HealthCare AG:

Factor Xa-Inhibitor: Promising results in three phase I studies

First data presented at the 45th Annual Meeting of the American Society of Hematology

Leverkusen, Germany
- A new oral anticoagulant - a direct Factor Xa inhibitor - in development by Bayer HealthCare´s Pharmaceuticals Division has shown highly promising results according to three phase I studies to be presented at the American Society of Hematology 45th Annual Meeting in San Diego today.

The results of two studies show that the oral Factor Xa inhibitor - with the internal project code BAY 59-7939 - offers predictable anticoagulation and is well tolerated with a rapid onset of action. Evidence for its predictable anticoagulation was supported first by the finding of a single-dose study of healthy male subjects and reinforced by the multiple-dose study data in which this drug achieved dose-dependent effects, with close correlation between pharmacokinetic and pharmacodynamic parameters.

Taking the findings of both the phase I multiple-dose and single-dose studies, oral BAY 59-7939 was shown not to prolong bleeding times or affect any standard safety parameters. Administered to over 200 subjects, BAY 59-7939 was very well tolerated even at the highest doses, with an excellent safety profile.

The third study, led by Dr Sebastian Harder (Institute for Clinical Pharmacology, University Hospital, Frankfurt), showed that oral BAY 59-7939 directly inhibits Factor Xa without the need for cofactors. This is an alternative mechanistic approach for an oral anticoagulant. Factor Xa is the pivotal point in the coagulation cascade where the intrinsic and extrinsic coagulation pathways coincide. Inhibition of Factor Xa can therefore directly regulate the final 'common pathway' of thrombin generation.

At present, there are no oral direct Factor Xa inhibitors available commercially.

Dr Kemal Malik, head of global medical development of Bayer HealthCare's Pharmaceuticals Division said: "We at Bayer are very enthusiastic about the prospects for BAY 59-7939 - it looks likely to provide predictable and safe anticoagulation in a clinical setting. At present, we are studying its potential use in the prevention and treatment of thromboembolic diseases where there is a clear medical need for improved treatment options. As an oral drug, BAY 59-7939 may be particularly useful in patients requiring anticoagulation both in and out of the hospital setting, including long-term prophylactic therapy. We expect to announce further results next year."

Bayer HealthCare AG, a subgroup of Bayer AG, with sales of approximately 9,4 billion Euro in 2002, is one of the world's leading, innovative companies in the health care and medical products industry. The company combines the global activities of the divisions Animal Health, Biological Products, Consumer Care, Diagnostics and Pharmaceuticals. More than 34,000 people are employed by Bayer HealthCare worldwide. Our aim is to discover and manufacture innovative products that will improve human and animal health worldwide. Our products enhance well-being and quality of life by diagnosing, preventing and treating disease.

Forward-looking statements<br/>
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.