Enzo Biochem Initiates Phase I Human Clinical Trials of Novel Genetic Medicine for Treatment of HIV-1 Infection.

FARMINGDALE, N.Y.--(BUSINESS WIRE)--July 13, 1998--Enzo Biochem, Inc. (ASE:ENZ), announced today that it has initiated Phase I human clinical trials of HGTV43, a genetic antisense-based therapeutic product designed to treat HIV-1 infected individuals. This product has been developed to protect human immune cells against infection by a broad spectrum of strains of HIV-1 including its mutational variants. The tests are being conducted at the University of California, San Francisco.

The Company said that the Phase I trials are designed to evaluate the safety of Enzo's novel therapeutic product. In addition, certain aspects of the trial will provide insight on how to formulate and deliver this medicine in the most effective manner. HGTV43, if it proves as successful in human clinical trials as has been shown in laboratory studies, could free HIV-1 infected patients from the need of other medications, some of which have debilitating side effects. Compliance with the regimen for current therapies has proven to be problematic; this new approach should avoid these problems.

At the recent World AIDS Conference in Geneva, Switzerland, Dean L. Engelhardt, Ph.D., Senior Vice President, gave a presentation that reported that in laboratory studies, the active genes cloned into HGTV43 had achieved between 92% and greater than 99% protection for human immune cells against HIV-1 infection.

"We have succeeded in developing a transducing vector that we believe is immunologically silent --- that does not produce any product that can be recognized as foreign to the body," said Dr. Engelhardt. "Furthermore, we have successfully demonstrated that we can create in the laboratory setting human immune cells that are resistant to HIV-1 and maintain that resistance to the virus over a prolonged period."

"Enzo's unique proprietary vector is expected to modify the immune cells with genetic antisense in such a manner that the cells should avoid cell destruction due to the normal surveillance properties of the body. This invention was critical for the long-term survival of the engineered cells and, therefore, is key to the effectiveness of the treatment," Dr. Engelhardt commented.

"This project represents Enzo's continuing effort in becoming a major contributor in the development of genetic medicine to treat diseases and genetic conditions that have proven to be unconquerable by conventional medical approaches," concluded Dr. Engelhardt.

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.

    CONTACT: Dean L. Engelhardt, Ph.D.,
              212/583-0100
              or
              Steve Anreder, 212/421-4020