Cerus and Baxter Present Phase III Results for the INTERCEPT Platelet and Plasma Systems At the American Society of Hematology Meeting.

Business Editors/Health & Medical Writers

ORLANDO, Fla.--(BUSINESS WIRE)--Dec. 10, 2001

Data To Be Used To Support Regulatory Submissions

Cerus Corporation (Nasdaq:CERS) and Baxter Healthcare Corporation today announced results of an extensive analysis of pivotal data from two separate Phase III clinical trials of the INTERCEPT Platelet System and the INTERCEPT Plasma System. The primary endpoints for both trials were successfully met. The companies are jointly developing INTERCEPT Blood Systems to protect against infectious disease transmission which may result from blood transfusions.

The results of the Phase III INTERCEPT Platelet System trial were presented by Jeffrey McCullough, M.D., professor of Laboratory Medicine and Pathology, University of Minnesota, at the American Society of Hematology (ASH) meeting being held in Orlando. The detailed analysis demonstrated that the primary endpoint for the 671-patient trial was successfully met and the results supported the use of INTERCEPT platelets to treat and prevent bleeding during severe thrombocytopenia, a medical condition characterized by a persistent reduction in platelet levels.

The primary endpoint of the platelet trial was designed to compare the incidence of moderate bleeding (Grade 2 World Health Organization criteria) in patients who received INTERCEPT platelets and those receiving untreated platelets to determine if the added feature of pathogen inactivation affected therapeutic benefit. The data showed that the proportion of patients with moderate bleeding was statistically equivalent between the two treatment groups and within one percent of each other, solidly achieving the trial's goal of a less than 12.5 percent difference in bleeding between the groups. In addition, secondary endpoints of more severe Grade 3 or 4 bleeding and duration of platelet support were not statistically different between the groups. The trial data also demonstrated that INTERCEPT platelets were associated with a statistically lower percentage of transfusion reactions than untreated platelets. Evaluation of other secondary measures of platelet count increment (measurements of post-transfusion platelet count increase) and number of platelet transfusions per patient showed a statistical difference between the INTERCEPT platelets and the untreated group, but these differences did not affect the primary trial goal of demonstrating equivalence in the proportion of patients with moderate bleeding between the two groups. Adverse events and serious adverse events were not statistically different between the groups and were consistent with expectations in the seriously-ill patient population undergoing intensive chemotherapy.

In a separate presentation on INTERCEPT platelets, Vic Ciaravino, Ph.D., director of Preclinical Safety at Cerus presented results of a comprehensive preclinical safety program. The studies were designed to evaluate safety of S-59, the active compound in the INTERCEPT Platelet System, at dose levels that are multiples of anticipated clinical exposures. The results of an extensive series of studies showed no clinically relevant toxicity at exposure levels that were 350 to 1000-fold the anticipated clinical exposure of S-59.

Also at ASH, results of the Phase IIIb trial of the INTERCEPT Plasma System were presented by David Ramies, M.D., director, Medical Affairs at Cerus. The 121-patient trial evaluated the blood clotting function of patients who received INTERCEPT plasma compared to those who received untreated plasma to determine whether the pathogen inactivation process affected therapeutic performance. This primary endpoint was successfully met and the results were statistically comparable between INTERCEPT plasma and untreated plasma to treat and prevent bleeding in patients with acquired defects in coagulation, primarily due to end-stage liver disease. In addition, safety and adverse events of INTERCEPT plasma compared to untreated plasma showed comparability between the two groups.

"With these data to support our regulatory submissions, we believe we are providing strong packages to the FDA as we seek approval of the INTERCEPT Platelet and Plasma Systems in the United States," said Stephen T. Isaacs, president and chief executive officer of Cerus. "Our INTERCEPT Platelet System is currently being reviewed by European regulators and we look forward to beginning the submission process for the plasma system in Europe as well."

Cerus and Baxter are collaborating on the development of the INTERCEPT Blood Systems to enhance the safety of blood transfusions. A CE Mark application seeking European approval for the INTERCEPT Platelet System has been submitted, and the companies have begun the regulatory submission process in the United States. Separately, the companies are preparing to begin the U.S. submission process for the INTERCEPT Plasma System which will be followed by a CE Mark application for this product. Baxter and Cerus intend to begin a Phase III clinical trial of the INTERCEPT Red Blood Cell System shortly.

About Cerus

Cerus Corporation is developing medical systems and therapeutics based on its proprietary Helinx(TM) 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 Systems, based on the company's Helinx technology, are designed to inactivate viruses, bacteria, other pathogens and white blood cells. The Concord, California-based company also is pursuing therapeutic applications of Helinx technology to treat and prevent serious diseases.

About Baxter

Baxter Healthcare Corporation is the principal domestic operating subsidiary of Baxter International Inc. (NYSE:BAX). Baxter is a global medical products and services company that, through its subsidiaries, provides critical therapies for people with life-threatening conditions. The company's products and services in bioscience (biopharmaceuticals, vaccines, biosurgery and transfusion therapies), medication delivery and renal therapy are used by health-care providers and their patients more than 100 countries.

Helinx is a trademark of Cerus Corporation

INTERCEPT Blood System, INTERCEPT Platelet System, INTERCEPT Plasma System and INTERCEPT Red Blood Cell System are trademarks of Baxter International Inc.

Statements in this news release regarding pre-clinical studies, clinical trials, regulatory filings, product development and product 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 process, additional financing activities, market acceptance of any products, competitive conditions and other factors discussed in the companies' most recent reports on Forms 10K, 10Q and other filings with the Securities and Exchange Commission.