Enzo Biochem Reports Interim Results for Clinical Trial of Alequel, Its Investigational Treatment for Management of Crohn's disease.

Business Editors/Health/Medical Writers

FARMINGDALE, NY--(BUSINESS WIRE)--March 11, 2004

Company Plans Expanded Study Based on Results

Enzo Biochem, Inc. (NYSE:ENZ), a leading biotechnology company specializing in gene identification and genetic and immune regulation technologies for diagnostic and therapeutic applications, today announced early interim results of its Phase II randomized double-blind study of Alequel(TM), the Company's investigational therapeutic modality for the management of Crohn's disease. Alequel(TM), a complex of autologous colon-derived antigens administered orally, was developed by Enzo based on the Company's proprietary immune regulation platform.

"Crohn's disease is a highly debilitating, widespread ailment often treated with systemic anti-inflammatory or immunosuppressive drugs that can result in serious complications," said Dean L. Engelhardt, Ph.D., Executive Vice President of Enzo. "These interim results are encouraging, and if our therapy is validated in further studies it could represent an exciting new treatment for bringing relief to many sufferers of the disease."

In this study, subjects with Crohn's disease were evaluated using the Crohn's Disease Activity Index (CDAI), a standard measure of the severity of the disease, with higher scores indicating more severe disease activity. Subjects with a baseline CDAI score between 220 and 400 were randomized in a double blind format in which one group received the study drug and a second group was given a placebo.

To date, of the subjects who participated in the study and completed the 15-week treatment period, with or without concomitant anti-inflammatory medication, 7 evaluable subjects received Alequel(TM), and 12 were given a placebo. 71% of the treated subjects achieved clinical remission, compared with 25% of the subjects who received the placebo. Clinical remission is defined as a CDAI score of less than 150 at three consecutive time points of 9, 12 and 15 weeks after initiation of treatment.

Of these same subjects, 71% of those who received Alequel(TM) showed a clinical response measured as a decrease of at least 70 in the CDAI score at the three consecutive time points of 9, 12 and 15 weeks after initiation of treatment. Of the placebo group, 42% showed a clinical response.

Quality of life was assessed by the Inflammatory Bowel Disease Questionnaire (IBDQ), an evaluation of health perception and function, completed by each subject before and at the end of treatment. The study drug group achieved a mean improvement of 45% in quality of life, while the placebo group achieved a mean improvement of 9%.

Based on these results, the Company plans to expand the study to broaden its statistical base, by increasing both the number of subjects and the diversity of the patient population to include a wider selection of individuals suffering from Crohn's disease, as well as to determine duration of the effects of the treatment. Enzo said that if the trial progresses as anticipated, results from the expanded study could be available before the end of the year. The Company is also evaluating plans for additional sites. The current study is being conducted at Hadassah Medical Center in Jerusalem, Israel.

Crohn's disease is a chronic, serious inflammatory disease of the gastrointestinal tract that affects at least one half million Americans, according to the Crohn's & Colitis Foundation of America. The disease is triggered by an immune mediated inflammatory response that can cause extensive intestinal damage. The disease usually is characterized by diarrhea, abdominal pain and fever, as well as loss of appetite and weight loss. Crohn's disease afflicts people of all ages, but most cases are diagnosed before age 30. Although similar to ulcerative colitis, which affects only the innermost lining of the colon, Crohn's disease involves all layers of the intestine.

About Enzo

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. The Company's proprietary labeling and detection products for gene sequencing and genetic analysis, with approximately 200 patents worldwide, are sold to the life sciences market throughout the world. The Company's therapeutic division is in various stages of clinical evaluation of its proprietary gene medicine for HIV-1 infection and its proprietary immune regulation medicines for hepatitis B and hepatitis C infection and for Crohn's disease. The Company also holds a patent covering a method and materials for correcting point mutations or small insertions or deletions of genetic material that would allow for editing and correcting certain abnormalities in genes. For more information visit our website www.enzo.com.

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. 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. The Company disclaims any obligations to update any forward-looking statement as a result of developments occurring after the date of this press release.