BioTransplant and The Massachusetts General
Hospital Announce Award of U.S. Patent Covering a
Novel Approach to Xenotransplantation Tolerance
- Company's Proprietary Portfolio Now Includes Six Gene Patents -
CHARLESTOWN, Mass., March 22 /PRNewswire/ -- BioTransplant Incorporated (Nasdaq: BTRN - news) and The
Massachusetts General Hospital (MGH) announced today the issuance of U.S. patent 6030833, ``Transgenic Swine and Swine
Cells Having Human HLA Genes.' This patent describes a novel method of modifying swine cells, organs and tissues so they can
be transplanted into a human recipient with reduced danger of rejection by natural killer (NK) cells. NK cells play a pivotal role in
immune responses against transplanted tissue. BioTransplant's XenoMune(TM)System is designed to provide immunological
tolerance of porcine tissue in human recipients, thereby increasing the availability of organs to patients.
``This patent supports the potential of our XenoMune(TM) technology to address the limited availability of organs for
transplantation,' stated Elliot Lebowitz, Ph.D., President and CEO of BioTransplant Incorporated. ``In conjunction with the $2.5
million milestone payment we received from our partner, Novartis AG, today's patent gives us a stronger strategic position in this
area.'
Proprietary Miniature Swine Included in Broad Patent
The patent extends to production of transgenic pigs, including miniature swine, that express a human nucleic acid encoding a Major
Histocompatibility Complex (MHC) class I protein. The advantages of BioTransplant's proprietary miniature swine include
matching human organ size requirements, the inbred nature of the herd and potential reduced infectivity to human cell lines from
porcine endogenous retroviruses (PERV).
The engineered swine cell covered by this patent can be a hematopoietic stem cell, a blood cell, a lymphoid cell (such as B or T
lymphocytes) or have its origin in the swine liver, kidney, epithelia, heart or thymus. The use of this graft engineering, in
combination with BioTransplant's proprietary methods of inducing tolerance, significantly increases the probability of xenogenic
graft acceptance.
A Multi-faceted Approach to Tolerance
The use of graft tissue which expresses MHC class I genes of the recipient species can be combined with BioTransplant's other
methods of inducing tolerance to optimize the procedure. Novel non-myeloablative conditioning regimens developed at MGH (U.S.
Patents 6006752 and 5876708) can induce tolerance at both the B and T cell levels by administering donor hematopoietic stem
cells. U.S. Patent 5658564 describes how swine thymus tissue may be introduced into the recipient to induce immunological
tolerance.
BioTransplant's Gene Patent Portfolio
This newly issued patent builds on the substantial Transplantation Gene Patent Portfolio held by or licensed to BioTransplant.
Previously, U.S. Patent 5614187, ``Specific Tolerance in Transplantation,' described a method to induce tolerance to swine
antigens by inserting the gene, encoding a swine MHC antigen into bone marrow hematopoietic stem cells of the recipient and
allowing this MHC antigen to be expressed and recognized as ``self.' U.S. Patents 5589582 and 5863528, Porcine Cytokines,
report the protein and DNA sequences of porcine cytokines that enhance proliferation and engraftment of bone marrow cells
across xenogeneic barriers. Porcine IL-10 and its purified DNA (U.S. Patent 5624823) and porcine CD34 may (U.S. Patent
5962644) also contribute to the induction of mixed chimerism and the inhibition of graft versus host disease.
BioTransplant Incorporated utilizes these proprietary technologies in re- educating the body's immune responses to allow functional
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.
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. |
