10/12/2004 GENEREX BIOTECHNOLOGY PRESENTS INFORMATION AT THE EUROCONFERENCE VACCINES 3 MEETING OF THE PASTEUR INSTITUTE IN PARIS ON THE USE OF NOVEL PEPTIDE VACCINE FOR MELANOMA
TRANSGENIC MICE STUDIES WITH GENES FOR HUMAN HLA-DR SUPPORT POTENTIAL USE OF T-HELPER CELL PEPTIDE VACCINE FOR CANCERS
TORONTO -- Generex Biotechnology Corporation (NASDAQ: GNBT) announced today that Dr. Robert Humphreys, founder of its Antigen Express immunomedicines subsidiary, delivered a presentation on October 7 at the Euroconference Vaccines 3 meeting of the Pasteur Institute in Paris, France.
Dr. Humphreys presented: "Enhanced T Helper Cell Epitope Peptide Vaccines for Melanoma." This presentation summarized work on a novel concept in melanoma vaccination by Antigen Express scientists during the past year in a special mouse model for melanoma vaccines. The transgenic mice used in this model contain the human HLA-DR molecules which present the vaccine peptides to mouse T helper cells. This is an advanced preclinical model, offering support for an Investigational New Drug filing for clinical trials.
Cancer clinicians in many academic cancer centers state that peptide vaccines have potential for immunotherapies of established and potentially recurrent cancers. Melanoma is one of the most advanced models for identification and use of such peptide vaccines.
Many vaccine peptides have been developed for stimulation of patients' cytotoxic T lymphocytes to kill cancer cells. However, clinical trials with such vaccine peptides do not have particularly robust results. The reason for this lack of potency stems in part from the fact that those vaccine peptides do not boost T helper cells, which upregulate the cytotoxic T lymphocytes and provide long term immunological memory.
Specific T-helper cell vaccine peptides that have been investigated are not potent because such peptides bind only weakly to the specialized receptors, which present the peptides to T-helper cells. Antigen Express' scientists have discovered and patented a method to enhance such presentation of peptides to T-helper cells.
The mechanism has been to create a hybrid linking the peptide recognized by T-helper cells through a simple chemical linker to an immunoregulatory segment of the Ii-protein (the Ii-Key peptide). Such Ii-Key peptide linked - epitope peptide hybrids are presented 200 times more effectively than the epitope-only peptide in vitro. Mice immunized with Ii-Key/antigenic epitope HIV hybrids demonstrated a 4-6 fold greater enhancement of Th1 cells than did mice immunized with HIV epitope-only peptides as measured by an immunological assay specific for T-helper cells.
Applying these methods to melanoma, Antigen Express scientists found similar results with Ii-Key hybrids containing melanoma epitopes. The enhancement of T helper activation probably augments cytotoxic T lymphocyte activity by stimulating dendritic cells. Thus, Ii-Key/melanoma hybrids for T helper cells can be used in combination with cytotoxic T lymphocyte epitope peptides for maximal clinical therapeutic effect.
The potency of other kinds of vaccine peptides is also greatly increased when linked to the Ii-Key active molecule. In addition to melanoma, Antigen is pursuing programs for the use of such vaccines for breast, colon and ovarian carcinomas as well as for HIV, SARS, and smallpox. Hybrids of the Ii-Key linked chemically to a number of antigenic epitopes have been demonstrated to be potent vaccines in mouse models.
Antigen Express has received 9 grants from the National Cancer Institute, the National Institute of Allergy and Infectious Diseases, and the Department of Defense for the development of these compounds for many vaccine and treatment purposes.
About Generex
Generex is engaged in the research and development of drug delivery systems and technology. To date, it has focused on developing a platform technology for the buccal delivery -- delivery to the oral cavity for absorption through the inner mouth mucosa -- of drugs that historically have been administered only by injection. Generex's buccal delivery technology has application to a large number of drugs. Generex acquired Antigen Express in August. 2003. The core platform technologies of Antigen Express comprise immunotherapeutics for the treatment of malignant, infectious, allergic, and autoimmune diseases.
This release and oral statements made from time to time by Generex representatives concerning the same subject matter may contain "forward-looking statements" within the meaning of the Private Securities Litigation Reform Act of 1995. These statements can be identified by introductory words such as "expects," "plans," "intends," "believes," "will," "estimates," "forecasts," "projects" or words of similar meaning, and by the fact that they do not relate strictly to historical or current facts. Forward-looking statements frequently are used in discussing potential product applications, potential collaborations, product development activities, clinical studies, regulatory submissions and approvals, and similar operating matters. Many factors may cause actal results to differ from forward-looking statements, including inaccurate assumptions and a broad variety of risks and uncertainties, some of which are known and others of which are not. Known risks and uncertainties include those identified from time to time in the reports filed by Generex with the Securities and Exchange Commission, which should be considered together with any forward-looking statement. No forward-looking statement is a guarantee of future results or events, and one should avoid placing undue reliance on such statements. Generex claims the protection of the safe harbor for forward-looking statements that is contained in the Private Securities Litigation Reform Act.
Shayne Gilliatt of Generex Biotechnology Corporation, 1-800-391-6755 or +1-416-364-2551; or Ken Sgro of CEOcast, Inc., +1-212-732-4300, kensgro@ceocast.com, for Generex Biotechnology Corporation
Shayne Gilliatt of Generex Biotechnology Corporation, 1-800-391-6755, or
+1-416-364-2551; or Ken Sgro of CEOcast, Inc., 212-732-4300,
kensgro@ceocast.com, for Generex Biotechnology Corporation
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