SangStat and Nextran (Baxter affiliate) announce FDA clearance for Cross-Stat monitoring product; Pra-Stat clinical data presented at ASTP in Chicago.

MENLO PARK, Calif.--(BUSINESS WIRE)--May 16, 1995--SangStat, The Transplant Company, (NASDAQ:SANG) and Nextran, an affiliate of Baxter Healthcare Corporation (NYSE:BAX), today announced that SanStat's second monitoring product, CROSS-STAT, had been cleared for marketing in the U.S. by the FDA under the 510(k) notification procedure. SangStat had submitted the application for marketing approval on January 6, 1995 and under its 1993 agreement with Baxter, earned $375,000 for the 510(k) clearance and $375,000 for the marketability.

CROSS-STAT is designed to identify prospective organ recipients that do not react with human leukocyte antigens (HLAs) present in the donor organ. This crossmatching procedure helps to identify an appropriate transplant candidate for the available organ and is often the final step prior to surgery in assessing donor/recipient compatibility.

The CROSS-STAT assay is based on patented soluble HLA (sHLA) monitoring technology pioneered by SangStat scientists. Soluble HLA molecules are very similar to cellular HLAs, but they are found in whole blood, plasma and serum and can be accurately and rapidly measured.

SangStat will manufacture CROSS-STAT which will be marketed worldwide by Baxter Healthcare Corporation, through a majority-owned affiliate called Nextran, under a collaborative agreement reached by the companies in 1993. CROSS-STAT is the second of the soluble HLA products under the agreement. Nextran launched the first product PRA-STAT last year. PRA-STAT, an Elisa test also developed using the soluble HLA technology, is designed to track the appearance and disappearance of anti-HLA antibodies in transplant candidates, and to analyze such antibodies. The information helps guide donor organ selection for each transplant candidate. Panel reactive antibody (PRA) testing is often performed every month on patients awaiting transplantation.

New clinical study findings on PRA-STAT were presented in Chicago during the fourteenth annual meeting of the American Society of Transplant Physicians (ASTP).

The retrospective study, presented by Ronald H. Kerman, M.D., Ph.D., of the University of Texas Medical School, Houston, compared the incidence of graft rejection after pre-transplant testing by the standard lymphocytotoxicity method with that predicted by PRA-STAT. The findings showed a clinically significant correlation between PRA-STAT-detected anti-HLA IgG antibodies before surgery and graft rejection incidence during the first 12 months after surgery (p<0.0001). In contrast, there was no correlation with standard lymphocytotoxicity (CDC) results. Kerman, who is professor of surgery and director of Histocompatibility and Immune Evaluation Laboratories, and his colleagues evaluated 123 patient serum samples high in CDC-PRAs and 100 samples low in CDC-PRAs, identifying predictive IgGs in both sample groups by PRA-STAT. Additional studies, reported during the ASTP meeting, performed by Dr. J. Kalil (Sao Paolo University Hospital, Brazil) and Dr. M. Jeannet (Geneva University Hospital, Switzerland), also demonstrated similar clinical correlation. Studies to evaluate CROSS-STAT's clinical significance are also ongoing.

Philippe Pouletty, M.D., chairman and CEO of SangStat and Rick Epstein, vice president of Nextran, said, "We are encouraged by these results. SangStat had demonstrated higher reproducibility of PRA-STAT as compared to lymphocytotoxicity in previous studies. The new findings now suggest that this assay might have clinical predictive power. Additional studies are in progress to evaluate various clinical endpoints."

There are approximately 80,000 transplant candidates registered on transplant waiting lists in the United States and Europe and 36,000 transplants are performed annually. Each year 15,000 donors provide multiple organs for transplantation. Due to the shortage of available organs, each is precious and every reasonable step to assure success of transplantation should be taken.

SangStat is a biopharmaceutical company dedicated to disease management in the field of organ transplantation. Of SangStat's eleven products and product candidates, one is a licensed-in, commercially proven drug, three are currently available for clinical and research use and several others are at an advanced stage of development. SangStat's drug candidates include THYMOGLOBULIN to treat graft rejection, CYCLOSPORINE for chronic immunosuppressive therapy and ALLOTRAP to promote graft acceptance following transplantation. THYMOGLOBULIN (exclusive marketing and development rights from Pasteur Merieux Serums et Vaccins "PMsv" for the U.S. and Canada) has been submitted for new drug approval in Canada, and is in a Phase III clinical trial in the U.S. The second drug candidate, CYCLOSPORINE, is in development; and ALLOTRAP is in early Phase II clinical trials in France. Monitoring products include PRA-STAT (marketed in the U.S. and Europe), CROSS-STAT and candidate TYP-STAT. These three products, intended to improve donor/recipient compatibility, are licensed exclusively worldwide to Baxter Healthcare Corporation. Other product candidates, QUANTSTAT, TRANSTAT,and sHLA-STAT Class I are intended to guide post-transplant therapy, CELSIOR (exclusively licensed from PMsv) is an organ preservation solution; and drug candidate XE-9 is in early development for xenotransplantation.

Nextran, formed in August 1994 as a partnership between Baxter Healthcare Corporation and DNX, is dedicated to the commercialization of innovative technologies, products and services useful to improve the success and increase the availability of organ transplantation. Nextran's portfolio includes marketing rights to three of SangStat's pre-transplant sHLA monitoring products. In addition, Nextran is developing therapeutic products to treat organ rejection and xenotransplantation technology (animal to human organ transplantation) to increase the availability of organs.

SangStat is located in Menlo Park, California, and operates wholly-owned subsidiaries XenoStat, Inc. in Menlo Park, California, SangStat Atlantique S.A. in Nantes, France and SangStat Canada Ltd. in Mississauga, Ontario, Canada.

Nextran is headquartered in Princeton, New Jersey.

CONTACT: SangStat

Philippe Pouletty, M.D., 415/328-0300

or

Russell-Welsh, Inc.

Katharine A. Russell, 415/312-0700