Enzo Biochem Initiates Phase II Study of Crohn's Disease Treatment.

Business Editors/Health/Medical Writers

FARMINGDALE, N.Y.--(BUSINESS WIRE)--June 9, 2003

Enzo Biochem, Inc. (NYSE:ENZ) announced today that it has initiated the Phase II randomized double-blind clinical trial of the Company's new treatment for Crohn's Disease.

The treatment is a complex of antigens administered orally and is based on Enzo's proprietary immune regulation platform. Crohn's Disease is a chronic, serious inflammatory disease of the gastrointestinal tract that affects at least one half million Americans.

Enzo said it has begun enrolling subjects for the Phase II clinical study which is being conducted at the Gastroenterology and Liver Unit at Hebrew University-Hadassah Medical Center, Jerusalem, Israel. Approximately 30 individuals will ultimately be enrolled. Each subject will be treated for 15 weeks and followed for an additional 12 weeks after treatment is completed.

The results of Enzo's Phase I trial were presented at the annual meeting of the American Association of Gastroenterology. During the course of the trial, all ten of the subjects showed a clinical response to the treatment, with seven achieving clinical remission. The ten subjects (six males and four females) presented with mild to moderate Crohn's Disease, and had suffered from the disease for an average of 11 years. Enzo's study drug was administered orally three times a week for a period of 16 weeks, and the subjects followed for an additional 16 weeks. Response was measured by a significant decrease in CDAI (Crohn's Diseases Activity Index), a standard measure of the severity of the disease. The median time of response to the treatment was five weeks. To date, no treatment related adverse events were noted in any of the subjects.

"We are encouraged by the promising results of this initial Phase I clinical study and look forward to validating our treatment in the new Phase II study," said Dean L. Engelhardt, Ph.D., Executive Vice President of Enzo. "Our novel approach for treatment would represent a truly major achievement that would bring relief to many sufferers of this highly debilitating disease, without the side effects found with current therapies."

Enzo's proprietary treatment is a unique approach designed to manage Crohn's Disease by specifically regulating the immune system. Many current methods of treatment are based on the use of general immune suppression approaches which can lead to significant side effects. No treatment-related adverse effects have been reported thus far with Enzo's treatment and it appears to be a safe and possibly effective treatment for individuals with Crohn's Disease. This treatment modality could provide a means of antigen specific immune regulation in the bowel for these individuals.

Enzo would anticipate utilizing its proprietary Crohn's Disease formula in a manner that would result in the creation of a personal medicine for each patient since the drug is manufactured from antigens removed from each individual. This could be the first in a line of personal medicine products.

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 conducting clinical trials of its proprietary gene medicine for HIV-1 infection and clinical trials of 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.