News Release

BAXTER AND ARRIVA PHARMACEUTICALS BEGIN CLINICAL TRIALS FOR RECOMBINANT ALPHA 1-ANTITRYPSIN

DEERFIELD, Ill. and ALAMEDA, Calif., March 4, 2003 -- Baxter Healthcare Corporation (Baxter) and its partner Arriva Pharmaceuticals, Inc. (Arriva) announced today the commencement of Phase I clinical trials in patients suffering from Alpha-1 Antitrypsin Deficiency, also known as hereditary emphysema. These clinical trials, being conducted in the United States, will evaluate the safety, immunogenicity, and tolerability of the jointly developed recombinant alpha 1-antitrypsin (AAT) therapy.

The companies' recombinant AAT is the first AAT product in clinical trials that is produced without the addition of human or animal-derived raw materials in the fermentation process, purification or final formulation. This recombinant AAT also has been developed to be delivered to the lungs of patients using a nebulizer. Current treatment for this condition involves intravenous infusion of plasma-derived alpha 1-antitrypsin, which is in limited supply, and cannot meet the current demand in the United States and Europe. While the plasma-derived treatment is effective, large doses are required to get therapeutic amounts of the protein to the lung where it is most needed.

"We are very pleased to be making progress in providing an advanced treatment for patients suffering from hereditary emphysema," said Martin J. Preuveneers, Ph.D., chairman and chief executive officer of Arriva. "We are delighted to be partnering with Baxter on this important trial."

Hereditary emphysema (HE) is a serious hereditary disorder characterized by low levels of the natural protease inhibitor AAT. Up to 100,000 individuals in the United States are affected by this disorder that, in certain cases, leads to excessive inflammation, progressive emphysema, and premature death if left untreated. The only drug treatment currently available for individuals with HE involves weekly infusion of a plasma-derived AAT that has been limited in supply. To address this gap in product supply in the meantime, Baxter announced in December an agreement with Alpha Therapeutic Corporation to acquire its plasma-derived AAT, Aralast, which was recently approved by the FDA. Until the acquisition is finalized, Baxter will serve as the exclusive, worldwide distributor of Aralast, and will be responsible for its launch.

Baxter's BioScience business develops and produces biopharmaceuticals from plasma and through recombinant methods to treat hemophilia, immune deficiencies and other blood-related disorders, as well as vaccines and biosurgery products.

Baxter Healthcare Corporation is the principal U.S. operating subsidiary of Baxter International Inc. (NYSE: BAX). Baxter assists health-care professionals and their patients with treatment of complex medical conditions, including cancer, hemophilia, immune disorders, kidney disease and trauma. The company applies its expertise in medical devices, pharmaceuticals and biotechnology to make a meaningful difference in patients' lives. For more information about Baxter, please visit www.baxter.com.

Arriva Pharmaceuticals, Inc., is a privately held biopharmaceutical company. The company's goals are to develop, manufacture and market clinical grade recombinant protease inhibitors. Arriva Pharmaceuticals, Inc. has developed technology for large-scale production of stable non-animal sourced recombinant proteins in Saccharomyces cerevisiae (Baker's yeast). The company's areas of therapeutic focus are:

• Respiratory diseases: HE, asthma, cystic fibrosis, chronic obstructive pulmonary disease (COPD), and other respiratory indications
• Dermatological diseases: atopic dermatitis, psoriasis

For more information about Arriva Pharmaceuticals, Inc., visit the company's Website www.arrivapharm.com.

This news release contains forward-looking statements that involve risks and uncertainties, including the timing and results of clinical trials and other development activities, actions by regulatory authorities at any stage of the development and commercialization process, economic conditions, market demand, the impact of competitive products and pricing, technological advances in the medical field and other risks detailed in the companies' filings with the Securities and Exchange Commission. These forward-looking statements are based on estimates and assumptions made by management of the companies and are believed to be reasonable, though are inherently uncertain and difficult to predict. Actual results or experience could differ materially from the forward-looking statements.

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