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PR Newswire
Antigen Express Announces Patent Award and $292,000 Phase I SBIR Grant for

April 29, 2002
WORCESTER, Mass., April 29 /PRNewswire/ -- Antigen Express, Inc. (AgExp) today announced that the US Patent and Trademark Office has issued to AgExp a new patent, US 6,368,855, concerning its Ii-Suppression Platform Technology. Additionally, AgExp has received a $292,000 Phase I Small Business Innovative Research (SBIR) grant from the National Cancer Institute (NCI) to extend the patented work in the development of a MHC Class II based intratumoral gene therapy to produce an in vivo therapeutic cancer vaccine that elicits a robust helper T-cell anti-cancer response.

This patent strengthens the AgExp intellectual property portfolio, which includes 5 issued US patents, 2 foreign patents, and additional patent applications both in the US and abroad. US 6,368,855 provides for composition of matter on molecular and genetic constructs that suppress Ii protein expression. The SBIR award is the third in a series of SBIR Phase I grants totaling $664,000 that AgExp has received over an 18-month period to advance its Ii-Suppression Platform Technology into the clinic for the treatment of solid tumors.

AgExp scientists have shown that cancer cells are robust vaccines when they express MHC Class II molecules, and the Ii (Invariant Chain) immunoregulatory protein is suppressed. Many cancer cells express MHC Class II molecules, or they can be readily induced with interferon gamma or the MHC Class II tranactivator. Endogenously synthesized antigens, which are transported into the endoplasmic reticulum for binding to MHC Class I molecules, are normally excluded from Class II binding because the invariant chain (Ii protein) blocks the MHC Class II antigenic peptide binding site.

Upon suppression of Ii protein expression with antisense methods, an enhanced repertoire of tumor cell antigenic epitopes becomes presented. This "uncloaking" of the cancer cell leads to a robust anti-cancer immune response.

The approach works with either cancer cells manipulated in cultures, or directly in vivo upon injection of the AgExp reagents into the tumor. The $292,000 SBIR will fund the continued development of AgExp's lead intratumoral gene therapy products delivered either in viral vectors, or as bound by lipids, or particles, in vivo. AgExp is focusing its efforts on intratumoral therapy for clinical use in patients with colorectal, breast, melanoma, and ovarian cancers.

AgExp and collaborators are also applying the Ii Suppression Technology Platform in the development of DNA vaccines for HIV and tumor antigens. By augmenting antigen presentation on MHC Class II molecules by antigen presenting cells (e.g., dendritic cells) that express the DNA vaccine gene, Ii Suppression enhances the cellular and antibody (humoral) responses obtained. In the same manner, the Ii-Suppression Technology Platform can be used to enhance the potency of a variety of cell-based therapies including dendritic cells, cancer cells (allogeneic and autologous), and dendritic/cancer cell fusions.

AgExp is a private biotechnology company that is developing a range of therapeutics for the treatment of cancer, autoimmune, infectious, and allergic diseases. The proprietary technology platforms are centered on MHC Class II antigen presentation and processing, the first step in the immune response. The AgExp technology focuses on the T-helper system, which is central to the induction of robust, long-lived responses and immunologic memory.

CONTACT: Joseph V. Gulfo, MD, MBA, of Antigen Express, Inc., +1-610-205-0100, or