News Release

NEWLY PUBLISHED DATA IN BLOOD CONFIRM THE THERAPEUTIC EFFICACY AND SAFETY OF INTERCEPT PLATELETS

First Pathogen Inactivation Blood Safety Technology for Platelets
Approved and Available for Use in Europe

BRUSSELS, BELGIUM and CONCORD, CALIF., March 18, 2003 -- The March 15 issue of the scientific journal Blood, the official journal of the American Society of Hematology, contains published data demonstrating that physicians in Europe can safely provide their patients with the added security of pathogen inactivated platelets while delivering the therapeutic benefits required of platelet transfusions. The pivotal European Phase III clinical trial data confirm the therapeutic efficacy and safety of the INTERCEPT Blood System for platelets, a new blood safety technology designed to protect patients by reducing the risk of transfusion-transmitted diseases such as HIV and hepatitis.

The study, known as the euroSPRITE trial, was one of the most extensive platelet transfusion clinical trials ever conducted in Europe in thrombocytopenic patients (patients with low platelet counts and at high risk for bleeding). The results were a determining factor in the INTERCEPT Blood System for platelets receiving European regulatory approval last year, making it the only pathogen inactivation system for platelets approved and available for use in Europe.

The study was designed to determine whether platelets treated with the INTERCEPT Blood System provided platelet transfusion support in preventing or stopping bleeding consistent with conventional medical practice. This included monitoring patients for bleeding and several secondary endpoints including acute transfusion reactions, as well as adverse events. The results showed that platelets treated with this new blood safety technology delivered comparable therapeutic benefits with no associated increase in patient adverse reactions.

"These results are particularly important as they indicate that platelets treated with the INTERCEPT Blood System offer the benefit of a prospective blood safety technology without compromising platelet performance or function," said Professor Dick van Rhenen, lead investigator and Director of Sanquin Blood Bank South West Region, Rotterdam, the Netherlands. "This is a significant advancement in the safety for patients undergoing chemotherapy, heart bypass surgery and other procedures that require platelet transfusions."

The randomized, double-blind and controlled trial compared conventional platelets with platelets treated with the INTERCEPT Blood System in 103 thrombocytopenic patients requiring repeated platelet transfusions for up to 56 days. The study included thrombocytopenic cancer and bone marrow transplant patients from four prominent medical centers in the United Kingdom, France, the Netherlands and Sweden.

The results of the euroSPRITE trial indicated that the platelets treated with the INTERCEPT Blood System were comparable in safety and efficacy to untreated platelets. In addition, both groups showed a comparable low incidence of bleeding, low numbers of red blood cell transfusions and low incidence of acute transfusion reactions. In this study, for specific patient groups the INTERCEPT Blood System also was used in place of gamma irradiation to inactivate white blood cells that can cause a fatal reaction in patients with damaged immune systems.

The INTERCEPT Blood System for platelets has been jointly developed by Cerus Corporation (Nasdaq: CERS) and subsidiaries of Baxter International Inc. (NYSE: BAX). With this technology, the two companies introduce a new, more comprehensive strategy for the protection of the blood supply by targeting a broad spectrum of pathogens associated with transfusion-transmitted diseases. The INTERCEPT Blood System for platelets uses a light-activated, nucleic acid-targeting compound that inactivates pathogens containing DNA and RNA, such as HIV and hepatitis B and C viruses, and prevents them from replicating. The technology also has been shown to inactivate emerging pathogens for which there are no current tests, such as West Nile Virus.

Clinical trials are underway for use of the INTERCEPT Blood System with plasma and red blood cells for transfusion, making it the only pathogen inactivation technology currently being developed for use with all primary blood components. The companies have begun the regulatory submission process for INTERCEPT Platelets in the United States.

Baxter International Inc., through its subsidiaries, 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.

Cerus Corporation is developing medical systems and therapeutics based on its proprietary Helinx® technology for controlling biological replication. Cerus' most advanced programs are focused on systems to enhance the safety of blood products used for transfusion. The INTERCEPT Blood System, based on the Cerus Helinx technology, is being developed to inactivate viruses, bacteria, parasites and white blood cells. The Concord, California-based company also is pursuing therapeutic applications of Helinx technology to treat and prevent serious diseases.

Cerus and Helinx are U.S. registered trademarks of Cerus Corporation.
Baxter and INTERCEPT Blood are trademarks of Baxter International Inc.

Statements in this news release regarding regulatory filings, product development and commercial potential are forward-looking statements that involve risks and uncertainties. Actual results could differ materially from the above forward-looking statements as a result of certain factors, including the risks and uncertainty of the timing and results of clinical trials and other development activities, actions by regulatory authorities at any stage of the development and commercialization process, additional financing activities, manufacturing, market acceptance of any products, competitive conditions and other factors discussed in the companies' most recent filings with the Securities and Exchange Commission.

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