Enzo Biochem Treatment Could Alleviate Crucial Debilitating Side Effects of Bone Marrow Transplantation, Paper Says.

Business Editors

FARMINGDALE, N.Y.--(BUSINESS WIRE)--May 23, 2000

Medical Conference Told of Results of Laboratory Studies

Using Enzo's Immune Enhancement Technology

Wasting response in humans as well as several forms of debilitating inflammation, among other side effects afflicting recipients of bone marrow transplantation may be significantly alleviated using a new treatment developed by scientists at Hadassah University Hospital and Enzo Biochem, Inc. (NYSE:ENZ). Such results were reported in a paper presented yesterday at a conference of leading medical scientists meeting in San Diego, CA.

The side effects are part of graft versus host disease (GvHD), an undesirable immune response mounted against an individual receiving a bone marrow stem cell transplant. This disease can occasionally lead to death. There is currently no effective treatment for chronic GvHD.

The paper detailing the Hadassah/Enzo studies using a mouse model system was presented by Yaron Ilan, M.D., of Hadassah University Hospital in Jerusalem, at the annual Digestive Disease Week Conference sponsored by several leading professional medical organizations. He reported on his collaborative research with scientists of Enzo Biochem, utilizing Enzo's immune enhancement technology. The paper was one of three featured on the cover of the current issue of the Journal of the American Gastroenterology Association, and it received a Distinction Award at the meeting.

This study demonstrated that oral administration of specific antigens effectively reversed the manifestations of chronic graft versus host disease. At the same time, the treated mice were shown to have undergone a favorable change in blood chemistry promoting a naturally occurring anti-inflammatory and anti-wasting response.

The results of this preclinical study, said Enzo, demonstrate that Enzo's immune enhancement regulation technology could be effective in negating the effects of GvHD by enhancing the anti-inflammatory immune response mounted by the donor tissue or cells. The treatment was effective in ameliorating liver, bowel and skin manifestations of GvHD, the paper reported.

"Graft versus host response, where donor immunological cells attack the recipient, is a common cause of failure in 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 from our animal studies."

"This procedure may also be useful for managing similar wasting and inflammatory reactions brought about by organ transplantation," added Dr. Engelhardt.

Enzo said that its treatment of graft versus host disease was one of three therapeutic applications the Company was preparing for clinical trials. In addition, the Company has underway two Phase 1 studies involving the management of diseases caused by HIV-1 and hepatitis B infection.

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 correct actual results.