NEW YORK, May 2 /PRNewswire-FirstCall/ -- Antigenics Inc. today announced the publication of research that provides support for the immunological mechanism of action of the company’s heat shock protein (HSP)-based investigational personalized cancer vaccines, Oncophage(R) (HSPPC-96) and AG-858 (HSPPC-70). The paper, published in the June 2005 issue of Nature Immunology, demonstrates that complexes of HSPs and peptides - such as those that comprise Antigenics’ cancer vaccines - are the necessary and sufficient form of antigen to activate a ‘killer’ T-cell immune response in vivo.
Based on the company’s proprietary HSP technology, Oncophage and AG-858 consist of HSP-peptide complexes from each patient’s cancerous tissue or cells. They are designed to capture the ‘antigenic fingerprint’ of the patient’s particular cancer, which is then used to reprogram the body’s immune system to target and destroy only cells bearing this fingerprint. Upon injection of vaccine, antigen-presenting cells take in, then process the HSP-peptide complexes, presenting the antigens on their cell surfaces to the killer (cytotoxic) T cells that are crucial in attacking infected and cancerous cells.
“The form in which antigens are transferred from diseased cells to antigen-presenting cells as part of the process of activating cytotoxic T cells has been a longstanding unresolved issue in immunology,” said Pramod Srivastava, PhD, Founding Scientist of Antigenics, Director of the Center for Immunotherapy of Cancer and Infectious Diseases at the University of Connecticut School of Medicine, and the lead author of the Nature Immunology publication. “This study adds to considerable evidence that HSP-chaperoned peptides play an important role in generating antigen-specific immune responses against cancers and infections, and provides a physiological basis to the continued exploration of HSP-based therapeutic applications.”
In the study, researchers investigated whether intact antigen or antigenic peptides chaperoned by heat shock proteins are required to generate killer T-cell immune response in a mouse model. Cell lysates were depleted of either intact antigen or the main heat shock proteins gp96, HSP90, HSP70 and calreticulin, which constitute more than 90 percent of the peptide-binding chaperones in cells. Both depleted lysates were used to immunize mice. Using two independent antigen systems, it was found that depletion of the four main HSPs resulted in complete abrogation of antigen-specific killer T-cell responses, whereas depletion of intact antigen had no influence on T-cell responses. These data show the centrality of the heat shock proteins for eliciting T-cell responses in a physiological setting.
About Antigenics
Antigenics is working to develop personalized immunotherapeutics and revolutionary treatments for cancers and infectious diseases. The company’s lead product candidate is Oncophage(R) (HSPPC-96), a late-stage, personalized cancer vaccine being evaluated in several indications, including renal cell carcinoma and metastatic melanoma. Antigenics’ portfolio also includes AG-858 (HSPPC-70), a personalized cancer vaccine in Phase 2 development; two Phase 2 liposomal cancer treatments, Aroplatin(TM) and ATRA-IV; and AG-702/AG-707, a Phase 1 genital herpes program. For more information, please visit http://www.antigenics.com/.
This press release contains forward-looking statements, including statements regarding the role played by HSP-chaperoned peptides in generating antigen-specific immune responses against cancers and infections, and their value in providing a physiological basis to the continued exploration of HSP-based therapeutic applications. These statements are subject to risks and uncertainties that could cause actual results to differ materially from those projected in these forward-looking statements. These risks and uncertainties include, among others, the factors described in exhibit 99.1 to our Form 10-K as filed with the Securities and Exchange Commission on March 31, 2005. Antigenics cautions investors not to place considerable reliance on the forward-looking statements contained in this press release. These statements speak only as of the date of this document, and Antigenics undertakes no obligation to update or revise the statements. All forward-looking statements are expressly qualified in their entirety by this cautionary statement. Antigenics’ business is subject to substantial risks and uncertainties, including those identified above. When evaluating Antigenics’ business and securities, investors should give careful consideration to these risks and uncertainties.
Antigenics Inc.
CONTACT: Sunny Uberoi, Corporate Communications,+1-212-994-8206, suberoi@antigenics.com; Jack Howarth, Investor Relations,+1-212-994-8244, jhowarth@antigenics.com
Web site: http://www.antigenics.com/