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Biotech / Medical : Biotransplant(BTRN) -- Ignore unavailable to you. Want to Upgrade?

To: keokalani'nui who wrote (910)	5/15/2001 4:00:05 PM
From: dalroi	Read Replies (1) \| Respond to of 1475

/FROM PR NEWSWIRE NEW YORK 800-776-8090/ [STK] BTRN [IN] MTC HEA BIO [SU] TO BUSINESS AND MEDICAL EDITORS: BioTransplant and Massachusetts General Hospital Announce Vital Link between Blood Cells and Transplantation Tolerance CHARLESTOWN, Mass., May 15 /PRNewswire/ -- BioTransplant Incorporated (NASDAQ:BTRN) and the Massachusetts General Hospital (MGH) today reported the detection of multilineage microchimerism in animals that had successfully accepted donor kidneys following transplantation of hematopoietic stem cells. The study reinforces the correlation between mixed chimerism and the induction of transplantation tolerance. These results will be presented today at the American Society for Transplantation (AST) Annual Meeting in Chicago by scientists from BioTransplant and the laboratory of David H. Sachs, M.D., Director of the Transplantation Biology Research Center at the Massachusetts General Hospital and Chairman of BioTransplant's Scientific Advisory Board. In the studies, miniature swine received a prototype of BioTransplant's AlloMune(TM) System and a 30 to 60 day course of cyclosporin as conditioning for a high-dose peripheral blood stem cell (PBSC) transplant from haploidentical donors. Blood cells originate from such stem cells, which subsequently differentiate into lymphoid, myeloid and erythroid lineages. These cells are transplanted in order to induce "mixed chimerism," the condition of a blended immune system between donor and recipient, so that the animal accepts donor cells as "self" while preserving its own immune cells as well. In separate studies, BioTransplant has demonstrated the cancer fighting applications of mixed chimerism. While the chimeric state keeps donor cells from attacking the recipient's healthy tissues, cancerous cells are not protected from the immune response. Examination of the peripheral blood showed that the majority of these PBSC recipients exhibited long-term (greater than 100 days) chimerism in the lymphoid lineage only. To determine whether the pigs possessed precursor cells from the donor animal, which are capable of evolving into multiple types of blood cells, bone marrow samples were taken. Using the highly sensitive "PCR" (polymerase chain reaction) assay, the cells were examined for evidence of donor DNA. Seven long-term recipients of hematopoietic stem cells were analyzed. Six of the seven demonstrated myeloid progenitor cells. Significantly, all six animals with multilineage chimerism detected by PCR accepted donor-matched kidney transplants without the need for further immunosuppression. The one recipient showing no evidence of multilineage chimerism rejected two renal allografts in succession. The correlation between multilineage mixed chimerism and survival of the renal graft without the deleterious and costly effects of long-term immunosuppression may have significant implications for the treatment of blood cancers and the future of solid organ transplantation. Approaches to augment the level and type of chimerism in these animals are currently under investigation. For several years, MGH and BioTransplant have been developing strategies for the induction of donor-specific tolerance through hematopoietic stem cell transplantation which allows successful organ allografting without the need for chronic immunosuppressive therapy. The procedure in this study follows a mild conditioning regimen that uses no irradiation and does not require life-long immunosuppressive therapy. A separate report between BioTransplant and MGH for end-stage renal disease and multiple myeloma, was also presented at the AST Annual Meeting. The study continued to show success in a double transplant procedure that freed two patients from the need for whole body irradiation to treat cancer. No rejection episodes have occurred, and both patients have continued normal kidney function without progression of myeloma for over 2.5 years and 6 months respectively, in the absence of chronic immunosuppressive drugs. The procedure also eliminates the need for life-long immunosuppressive drugs to prevent donor graft rejection. Elliot Lebowitz, Ph.D., BioTransplant's President and C.E.O. said, "Our AlloMune(TM) System for Cancer utilizes a number of advanced approaches designed to facilitate the acceptance of donor cells and tissue by the human immune system. We will continue to develop this technology, which is designed to enable long-term acceptance of transplanted cells, tissues and organs by re-educating the patient's immune system to recognize donor tissue as self." The Massachusetts General Hospital, established in 1811, is the original and largest teaching hospital of the Harvard Medical School and conducts the largest hospital-based research program in the United States. The MGH has major research centers in transplantation biology, the neurosciences, cardiovascular research, cancer, AIDS, cutaneous biology and photomedicine. Along with the Brigham and Women's Hospital, the MGH is a founding member of Partner's HealthCare System, Inc. an integrated health care delivery system comprising the two academic medical centers, specialty and community hospitals, a network of physician groups and non-acute and home health services. BioTransplant Incorporated utilizes its proprietary technologies to re-educate the body's immune responses to allow tolerance of foreign cells, tissues and organs. Based on this technology, the Company is developing a portfolio of products for application in a range of medical conditions, including organ and tissue transplantation, and treatment of cancer and autoimmune diseases, for which current therapies are inadequate. BioTransplant's products under development are intended to induce long-term functional transplantation tolerance in humans, increase the therapeutic benefit of bone marrow transplants, and reduce or eliminate the need for lifelong immunosuppressive therapy. This release and additional information on BioTransplant is available on the Web at biotransplant.com.