Monday January 31, 9:15 am Eastern Time
Company Press Release
SOURCE: BioTransplant Incorporated
Massachusetts General Hospital and BioTransplant
Incorporated Report Advances in Organ Transplantation and
Immunocompetency
-- Thymic Transplantation Studies Published in Transplantation and The Journal of Immunology
--
BOSTON, and CHARLESTOWN, Mass., Jan. 31 /PRNewswire/ -- The Massachusetts General Hospital (MGH) and
BioTransplant Incorporated (Nasdaq: BTRN - news) today announced scientific advances in organ transplantation and
immunocompetency that may hold promise for the treatment of a variety of diseases. Results published in the December 1999
issue of Transplantation demonstrated for the first time successful reconstruction of the immune system in a large animal
following a functional thymic graft and tolerance to a foreign organ graft. In a separate study, published in The Journal of
Immunology, scientists described advances in thymic grafting that induced tolerance of human T cells to porcine tissues and
restored immune system competency in immunodeficient mice. Both studies were performed by MGH researchers.
Megan Sykes, M.D., Immunologist at the Transplantation Biology Research Center at MGH, and Professor, Harvard Medical
School, stated, ''Creating immune system tolerance to transplanted cells and organs remains the 'holy grail' in transplantation
medicine and holds the key to expanding the number of patients who could benefit from transplants. Our preliminary results in
achieving immunological tolerance using thymic transplantation are promising for both organ transplant and immune deficient
patients.''
Elliot Lebowitz, Ph.D., President and CEO, BioTransplant Incorporated, noted, ''These results hold significance for
BioTransplant's core proprietary technology which is designed to re-educate the immune system, allowing tolerance of foreign
organs, cells and tissues. We believe that our continuing work with MGH, coupled with our strong patent portfolio, has
positioned us to become a leader in this field.''
The study in Transplantation is based on using the thymokidney, a new transplantable organ created by grafting thymus tissue
into the kidney capsule of the same miniature swine. Once the thymokidney became vascularized, it was transplanted to a
thymectomized foreign miniature swine that was immunodeficient with few circulating T cells. As a result, the recipient
recovered immunocompetency and was unresponsive to donor-specific challenges. The transplanted foreign thymokidney had
long-term renal function in the absence of chronic immunosuppressive drugs.
The second study described a novel way to achieve cross-species tolerance among human T cells. Porcine fetal thymic grafts
were found to support the development of functional, normal human T cells in immunodeficient mice. These human T cells
showed specific immunological tolerance to matched donor porcine antigens, while mounting immune responses against
mismatched human and porcine antigens. These results established the principle that human T cell tolerance can be induced to a
specific porcine donor.
In a related study, Dr. Sykes presented data at the 5th International Congress for Xenotransplantation in Nagoya, Japan in
1999, in which she detailed her experiments showing that natural antibodies in the sera of gal knockout mice do not prevent the
engraftment and function of porcine thymic xenografts in mice. This has important implications for pig to human thymus
transplantation because humans also make natural antibodies that might potentially pose a barrier to porcine thymic engraftment.
Augmenting these advancements is the award of U.S. Patent #5,658,564, ''Xenograft Thymus'', to Dr. Sykes and David
Sachs, M.D., Director of the TBRC at MGH in August 1997, and exclusively licensed to BioTransplant. The patent features
methods of restoring or inducing immunocompetence in a recipient by introducing thymic tissue, enabling the re-education of
host T cells which can mature in the implanted thymic tissue. This xenogeneic thymus-grafting approach holds potentially
important ramifications for the treatment of patients infected with HIV, as well as for cell, tissue and organ xenotransplantation.
One of the target organs of HIV is the thymus. Porcine thymic implantation combined with anti-retroviral therapy may lead to
adequate human thymopoiesis and as a result may strengthen the patient's immune response.
BioTransplant's approach to transplantation, focusing on functional tolerance (ImmunoCognance(TM)), is based on the
pioneering work of Dr. Sachs who is also Chairman of BioTransplant's Scientific Advisory Board. ImmunoCognance(TM) may
allow the recipient's immune system to accept donor cells or tissue as ''self'' without compromising the recipient's immune
defenses. This is achieved by mixing elements of the donor's immune system with that of the recipient and may have applications
in cancer, organ transplantation and hematological disorders.
BioTransplant Incorporated utilizes its proprietary technologies in re- educating 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 designed to
treat a range of medical conditions, including organ and tissue transplantation, cancer and autoimmune disease for which current
therapies are inadequate. BioTransplant's products 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.
The Massachusetts General Hospital, established in 1811, is the original and largest teaching hospital of Harvard Medical
School. The MGH conducts the largest hospital-based research program in the United States, with an annual research budget
of more than $200 million and major research centers in AIDS, the neurosciences, cardiovascular research, cancer, cutaneous
biology, transplantation biology and photomedicine. In 1994, the MGH joined with Brigham and Women's Hospital to form
Partners HealthCare System, 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.
This announcement contains, in addition to historical information, certain forward-looking statements about BioTransplant that
involve risks and uncertainties. Such statements reflect management's current views and are based on certain assumptions.
Actual results could differ materially from those currently anticipated as a result of a number of factors. Factors that could cause
future results to differ materially from such forward-looking statements include, but are not limited to: BioTransplant's ability to
secure the substantial additional funding required for its operations and research and development programs; BioTransplant's
ability to successfully discover, develop and commercialize its products, obtain required regulatory approvals in a timely
fashion, and overcome other difficulties inherent in developing pharmaceuticals and procedures for organ transplantation;
BioTransplant's ability to obtain and enforce the patent protection required for its products; uncertainties to the extent of future
government regulation of the transplantation business; and BioTransplant's ability to maintain collaborations with third parties.
For a detailed discussion of these and other factors, see the section titled ''Business - Factors Which May Affect Results'' in
BioTransplant's current annual report on Form 10-K, as filed with the Securities and Exchange Commission.
SOURCE: BioTransplant Incorporated |
