Enzo Biochem Receives Approval for Human Trial for New Medicine to Treat Hepatitis C and Associated Liver Cancer.

Business & Medical Editors

FARMINGDALE, N.Y.--(BUSINESS WIRE)--Nov. 30, 2000

Trial to Test New Enzo-Developed

Broad Spectrum Antigen Immune Regulation Product

Enzo Biochem, Inc., (NYSE:ENZ), a leading biotechnology company specializing in gene identification and gene regulation technologies for diagnostic and therapeutic applications, announced today that it has received approval from the Ministry of Health in Israel to commence a Phase I double-pronged human clinical trial to test a novel treatment for both chronically ill patients suffering from hepatitis C infection or its associated hepatocellular carcinoma (liver cancer). The trial is designed to evaluate a new proprietary broad-spectrum immune regulation medicine developed by Enzo.

Hepatitis C virus (HCV) affects approximately 170 million people worldwide. There are 3.9 million people in the U.S. with HCV, of which approximately 69%, or 2.7 million, are chronically infected, according to the National Center for Infectious Diseases. Individuals infected with HCV experience extreme fatigue, jaundice, abdominal pain, loss of appetite and vomiting. Approximately 30,000 new infections are recorded each year in the U.S. About 85% of people infected with HCV are reported to develop chronic hepatitis, and about 20% develop cirrhosis, an incurable disease, with approximately half of theses cases progressing to end-stage liver disease, including liver cancer. It has been predicted that HCV-related deaths in the U.S. may soon overtake the number of AlDS-related deaths in the U.S.

Hepatocellular carcinoma is the most common type of primary liver cancer, accounting for about 84% of the cases. The American Cancer Society estimates that approximately 15,300 new cases of this cancer wi1l be diagnosed in the U.S. this year and about 13,800 people will die from it. The incidence of liver cancer is far more common in Africa and Asia, and in some of those areas is the most common type of cancer.

In Dallas, Texas, last month, researchers reported on preclinical animal studies using a similar Enzo proprietary strategy of immune regulation. These studies showed complete suppression of hepatitis B-associated human liver cancer and significantly reduced mortality in laboratory mice. The paper was presented at a plenary session of the American Association for the Study of Liver Diseases, and was the result of a study conducted by researchers at Hadassah University Medical Center in Jerusalem, Israel in collaboration with Enzo scientists.

The newly approved Enzo Phase I clinical study will be conducted by physicians at the Liver Unit of Hadassah University Medical Center. Two groups of patients will be enrolled - those chronically infected with HCV and those with HCV-associated hepatocellular carcinoma. Each patient will be treated for 30 weeks, and followed for another 20 weeks.

"This product, consisting of a broad spectrum of antigens, is the next generation of our immune regulation medicine, and stems from our work in the development of EHT899 for the treatment of hepatitis B virus infection, which has demonstrated favorable early stage results," said Dean L. Engelhardt, Ph.D. Executive Vice President of Enzo. "The new trial for HCV treatment will evaluate safety and toxicity as well as efficacy and, if the medicine proves satisfactory, it will result in an important new, effective and relatively efficient treatment for both chronic HCV infection and its associated hepatocellular carcinoma."

The principal treatment today for HCV involves injections of interferon, a protein that interferes with viral growth, combined with ribavirin, a broad-spectrum antiviral agent. The interferon-ribavirin treatment typically is completed in six months to a year, with eradication of the virus occurring in about 40% of those receiving the treatment, according to reports. There is no known effective treatment for hepatocellular carcinoma, which usually leads to death.

This clinical trial will be funded in part by a grant received by Enzo in January 2000 from the Israel-U.S. Binational Industrial Research and Development Foundation. The grant was earmarked for expansion of Enzo's human clinical trials based on the Company's proprietary immune regulation platform for treatment of patients infected with hepatitis viruses.

The new study for treatment of HCV represents Enzo's third therapeutic product in human clinical trial. The Company is conducting a Phase I trial of HGTV-43, Enzo's gene medicine for HIV-infected patients, now nearing completion, and a Phase II trial of Enzo's EHT899 immune regulation medicine for 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 affect actual results.