Enzo Biochem Development May Aid Bone Marrow Transplantation; Scientist Reports Studies at American Association of Liver Diseases.

FARMINGDALE, N.Y.--(BUSINESS WIRE)--Nov. 9, 1999--

Recent laboratory studies indicate that the success of bone marrow transplantation may be significantly improved, using a new treatment developed by Enzo Therapeutics, a subsidiary of Enzo Biochem, Inc. (ASE:ENZ), it was reported at an international conference of leading scientists, meeting in Dallas.

The paper was presented by Yaron Ilan, M.D., of Hadassah University Hospital in Jerusalem, speaking at the meeting of the American Association for the Study of Liver Diseases on his collaborative research with scientists of Enzo Biochem, utilizing the Company's immune modulation technology, SIDR(TM).

The experiments involved a model system in which mice were transplanted under conditions that would cause graft versus host disease (GvHD) to occur. In GvHD an immune mediated attack by transplanted cells results in inflammatory damage of host organs. In previous work using Enzo's immune modulation therapy, orally administered antigens were shown to successfully inhibit GvHD inflammatory response, and effectively prevent the manifestations of the disease. Dr. Ilan reported that in the current studies he was able to show that "oral tolerization of recipient mice who have already developed GvHD could successfully down regulate the immune attack by the transplanted cells, thus ameliorating the GvHD.

Graft versus host disease (GvHD), which manifests as a multi-organ disorder, is a major complication of bone marrow and stem cell transplantation and accounts for much of the medical complications associated with these transplants. GvHD is an immune response mounted by the engrafted tissue or cell population against the recipient. It can occasionally lead to death. There is currently no effective treatment for chronic GvHD, however the results of this preclinical study demonstrate that Enzo's immune modulation technology could be effective in negating the effects of GvHD by controlling the immune response mounted by the donor tissue or cells.

Enzo said that planning is underway to begin clinical studies of its treatment.

"Graft versus host response, where donor cells immunologically attack the recipient, is often seen as a medical complication of bone marrow and stem cell transplants," said Dean L. Engelhardt, Ph.D., Senior Vice President of Enzo. "It is our intention to develop a product for use in humans to manage this serious condition and we are highly encouraged by the promising results of these studies."

Enzo Biochem is engaged in the research, development and manufacture of innovative health care products based on molecular biology and genetic engineering techniques, and in providing diagnostic services to the medical community.

Except for historical information, the matters discussed in this news release may be considered "forward-looking" statements within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended. Such statements include declarations regarding the intent, belief or current expectations of the Company and its management. Prospective investors are cautioned that any such forward-looking statements are not guarantees of future performance and involve a number of risks and uncertainties that could materially affect actual results.