Data from Enzo Therapeutics' Phase II Study of Crohn's Disease Presented at Prestigious Gastroenterology Conference

Study Meets Primary and Secondary Endpoints

NEW YORK--(BUSINESS WIRE)-- Enzo Biochem, Inc. (NYSE: ENZ), a biotechnology company specializing in gene identification and genetic and immune regulation technologies for diagnostic and therapeutic applications and laboratory services, announced that data from a Phase II clinical trial was presented today at Digestive Disease Week, the largest international gathering of academic researchers and practicing physicians in gastrointestinal medicine, held this year in Chicago. The data indicate that Alequel(TM), the Company's investigational individualized oral immune regulation preparation, may be effective for the treatment of moderate-to-severe Crohn's disease.

Medical researchers from Hebrew University-Hadassah Medical Center, Jerusalem, Israel, presented an abstract titled, "Oral Administration of Alequel(TM), a Mixture of Autologous Colon-Extracted Proteins for Treatment of Crohn's Disease: Results of a Double-Blind Clinical Trial," which highlighted data from a study, sponsored by Enzo Therapeutics, a wholly-owned subsidiary of Enzo Biochem. Subjects (n=43) with moderate to severe Crohn's disease were enrolled in a randomized, placebo-controlled, double-blind clinical trial. Subjects were randomized to receive either placebo or Alequel(TM) over a period of 15 weeks. The subjects were monitored for Crohn's Disease Activity Index (CDAI), Inflammatory Bowel Disease Questionnaire (IBDQ) and a number of potential surrogate biomarkers.

The primary endpoint was the remission rate, defined as a CDAI score of 150 or less at 2 consecutive time points 3 weeks apart. The remission rate was calculated for evaluable patients at 3-week intervals. Measuring between weeks 6 and 9, 43% of the investigational drug recipients met the criteria for clinical remission, versus 31% of the placebo recipients. For weeks 9 to 12, the remission increased to 50% of subjects receiving the investigational drug compared to 31% in the placebo group. Mean percent change in IBDQ quality-of-life score was 3 times greater after 15 weeks of treatment for subjects treated with Alequel(TM) compared to placebo.

To evaluate possible surrogate markers for the clinical effect of the drug, peripheral blood T-cell subpopulations were analyzed for each subject.

The data presented indicate a decrease in both peripheral NKT regulatory cells and the CD4+/CD8+ T lymphocyte ratio in subjects receiving Alequel(TM) who responded positively to the test drug, compared to subjects receiving Alequel(TM) who did not respond positively. A decrease of 28% vs an increase of 16% in peripheral NKT regulatory cells, and a decrease of 15% vs. an increase of 11% in the CD4/CD8 lymphocyte ratio, in drug responders vs. non responders respectively were noted only in subjects with a significant clinical response. It is believed that these immune cells may serve as surrogate markers to predict those individuals who would respond to the treatment. The applicability of these surrogate markers is being considered for further study.

The study also met secondary endpoints for improved quality of life as measured by IBQD scores, as well as overall safety and tolerability. No treatment-related adverse events were noted.

"We are pleased with the results of this clinical trial," said Elazar Rabbani, PhD, CEO of Enzo. "Alequel(TM) is a unique investigational drug in that it is designed to harness the patient's own immune system to alleviate symptoms of Crohn's disease, suggesting a new approach for a disease with few current treatment options. Alequel(TM) is designed to reduce the patient's dependence on systemic immunosuppressant drugs that often have undesirable side effects. Alequel appeared to be well-tolerated and improved the individual's quality of life. We believe these results further validate the potential for Alequel and we are examining our options to maximize the opportunities for this program."

About Crohn's disease

CD is an idiopathic, immune-mediated disorder currently believed to result from a cascade of processes initiated by unidentified antigens. This inflammatory disease of the GI tract affects approximately 500,000 people in the United States and at least that many in the rest of the world. The disease is characterized by flare-ups of symptoms such as diarrhea, abdominal pain, rectal bleeding and loss of appetite, alternating with periods of remission. Systemic complications of chronic disease include weight loss, anemia and increased risk of bowel cancer.

About Enzo

Enzo Biochem is engaged in the research, development, manufacture and licensing of innovative health care products and technologies based on molecular biology and genetic engineering techniques, and in providing diagnostic services to the medical community. Enzo's Life Sciences division develops, produces and markets proprietary labeling and detection products for gene sequencing, genetic analysis and immunological research among others. Its menu of over 40,000 products serves the molecular biology, drug discovery and pathology research markets. The Company's therapeutic division is in various stages of clinical evaluation of its proprietary immune regulation medicines for uveitis and Crohn's Disease and conducts pre-clinical research on several candidate compounds aimed at producing new mineral and organic bone, including technology that could provide therapy for osteoporosis and fractures, among other applications. Enzo's Clinical Labs division provides routine and esoteric reference laboratory services for physicians in the New York Metropolitan and New Jersey areas. Underpinning the Company's technology and operations is an extensive intellectual property estate in which Enzo owns or licenses over 230 patents worldwide, and has pending applications for over 200 more. 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.

    Source: Enzo Biochem, Inc.

Released June 2, 2009