Cerus Corporation Reports Positive Outcome in European Study of 7-Day INTERCEPT Platelets

Cerus Corporation (NASDAQ: CERS) announced today that INTERCEPT-treated platelet components were found to be effective for patient support following extended six and seven day storage in a clinical study conducted at four sites in Europe. These data further confirm the safety and therapeutic efficacy of platelets treated with the INTERCEPT Blood System, a pathogen inactivation treatment designed to protect against transfusion-transmitted diseases.

"This study shows that INTERCEPT platelets remain therapeutically effective even after six or seven days of storage," said Dr. Miguel Lozano of the Hospital Clinic in Barcelona, Spain, the study's lead investigator. "The ability to store platelets longer than five days can be critical to maintaining an adequate supply, but extended storage of conventional platelets creates an increased risk of transfusion-transmitted bacterial infection.

Therefore, the use of INTERCEPT treatment with its capacity to inactivate bacteria while maintaining platelet functionality contributes to guaranteeing both platelet safety and availability."

In accordance with CE marking, INTERCEPT platelet components are approved for storage up to seven days subject to local regulatory guidelines. The purpose of the 201-patient study was to provide additional information for clinicians regarding the safety and efficacy of INTERCEPT platelets compared to conventional platelets stored for six to seven days prior to transfusion. Most prior INTERCEPT clinical studies have included platelet units stored only up to five days.

The randomized, controlled, double-blinded study included platelet-deficient cancer patients at four medical centers in Spain, the United Kingdom, Sweden and France. The trial met its primary endpoint, defined as statistical non-inferiority of the INTERCEPT platelet one-hour corrected count increment compared to conventional platelet components. The corrected count increment measures the increase in the patient's platelet count following a platelet transfusion, adjusted for dose and patient blood volume. The absolute difference in one-hour corrected count increment between the INTERCEPT and control groups was approximately 13 percent, similar to differences observed in previous studies. Secondary endpoints included additional factors relevant to evaluation of clinical efficacy and safety. Mean one-hour count increments were not statistically significantly different between INTERCEPT and control arms, with absolute count increments of 19.4 and 21.6 (x 10⁹/L) respectively. Count increments taken 24 hours following transfusion were statistically significantly lower in the INTERCEPT study arm. However, no differences were observed in the time to next platelet transfusion, the number of red cell transfusions, the post-transfusion hemostatic scores, or the incidence of transfusion reactions and other adverse events. The investigators plan to submit data from the study for presentation at the International Society of Blood Transfusion's annual congress in June.

"We are pleased with the results of this study, which are consistent with previous observations that INTERCEPT platelets are therapeutically equivalent to conventional platelets," said Dr. Laurence Corash, Cerus' Chief Medical Officer. "Randomized, controlled clinical data from multi-center studies is important to our customers, to national transfusion services and to local regulatory authorities, and we look forward to the publication of the investigators' findings."

Despite testing and other measures, bacterial contamination of conventional platelet components persists, and concern has led to storage limits of four or five days in many regions. Collection and supply logistics have a significant impact on cost, and are particularly challenging over holiday periods when donation rates decline. Moreover, Germany's recent one day reduction of the conventional platelet storage limit, to four days, has resulted in wastage rates approaching 20 percent in some centers. Certain countries have granted storage extensions for up to seven days when anti-bacterial measures, including pathogen inactivation, are used during platelet production. In contrast to bacterial detection screening, INTERCEPT pathogen inactivation allows earlier release of platelets and provides protection against a broader spectrum of transfusion-transmitted diseases.

ABOUT THE INTERCEPT PLATELET SYSTEM

The INTERCEPT Blood System for platelets is designed to reduce the risk of transfusion-transmitted diseases by inactivating a broad range of pathogens such as viruses, bacteria and parasites that may be present in donated blood. The nucleic acid targeting mechanism of action allows INTERCEPT treatment to inactivate both established transfusion threats, such as hepatitis, HIV, West Nile virus and bacteria, as well as emerging pathogens such as influenza, malaria and dengue. The platelet system was granted CE mark registration in 2002, and subsequently received additional European regulatory approvals in France (Afssaps), Switzerland (Swissmedic), and Germany (Paul Ehrlich Institute marketing authorization for the German Red Cross). An estimated over 300,000 units of INTERCEPT platelets have been transfused to date.

ABOUT CERUS

Cerus Corporation is a biomedical products company focused on commercializing the INTERCEPT Blood System to enhance blood safety. Cerus currently markets and sells the INTERCEPT Blood System for both platelets and plasma in Europe, Russia, the Middle East and selected countries in other regions around the world. The INTERCEPT red blood cell system is in clinical development. See http://www.cerus.com for more information.

INTERCEPT and the INTERCEPT Blood System are trademarks of Cerus Corporation.

Cerus Corporation
Lainie Corten, 925-288-6319
Director, Global Communications & Marketing