Stressgen Biotechnologies Corporation’s European Patent Upheld Against Antigenics’ Challenge

SAN DIEGO, CA, Oct. 19 /PRNewswire-FirstCall/ - Stressgen Biotechnologies today announced that it has received a favorable decision in its patent challenge by Antigenics from an Opposition Division of the European Patent Office that maintained the Company’s European Patent EP-B1 1,002,110 in amended form. The Opposition by Antigenics was therefore dismissed, although they have the right to appeal this decision.

Oppositions can be filed by third parties at the European Patent Office against European patents to challenge their validity. Antigenics filed an Opposition to Stressgen’s patent in 2003, and cited over 140 documents to support its invalidity arguments. After fully considering the documents and extensive written and oral arguments of opposing counsel, the European Patent Office announced its decision, favorable to Stressgen, on October 19, 2005. This patent can be kept in force until 2018.

“We are obviously pleased that an Opposition Division of the European Patent Office has upheld our patent,” commented Gregory M. McKee, President and CEO of Stressgen. “This successful ruling maintaining the original patent provides further evidence of the strength of our heat shock protein intellectual property portfolio, and in particular, reinforces an important composition-of-matter patent covering our lead product candidate, HspE7.”

The Opposition Division of the European Patent Office held that the amended claims involve inventive step and are fully enabled. These claims cover fusion proteins comprising a heat shock protein, or portions thereof, and a human papillomavirus (HPV) protein antigen, or portion thereof, and being capable of inducing or enhancing a cell-mediated, cytolytic immune response in patients. The claims also cover related embodiments, such as nucleic acids encoding the fusion protein and pharmaceutical compositions containing the fusion protein.

About Stressgen Biotechnologies Corporation

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Stressgen, a biopharmaceutical company, focuses on the discovery, development and commercialization of innovative therapeutic vaccines for the treatment of infectious diseases and cancer. The corporation is publicly traded on the Toronto Stock Exchange under the symbol SSB.

About HspE7, Lead Product Candidate

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HspE7 is a novel CoVal(TM) fusion therapeutic vaccine designed for the treatment of diseases caused by the human papillomavirus (HPV), one of the most common causes of sexually transmitted diseases in the world. An estimated 80% of sexually active men and women are infected by genital HPV at some point in their lives. Approximately 5.5 million new sexually transmitted HPV infections are reported in the U.S. each year. At least 20 million people in the U.S. are already infected. HPV infection can result in diseases including internal and external genital warts and precancerous conditions, such as cervical and anal dysplasia. Precancerous HPV-related conditions can progress into life-threatening diseases, including cervical, anal, and head and neck cancers.

About CoVal(TM) Fusion Proteins

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Stressgen capitalizes upon the immunostimulatory powers of heat shock proteins utilizing recombinant technology to fuse, or covalently link, a stress protein with a protein antigen to create a single hybrid protein designed to trigger the immune system to recognize that antigen. For more information about CoVal(TM) fusion technology, or Stressgen, please visit the website located at www.stressgen.com.

This press release contains forward-looking statements regarding our intention to pursue initiatives focused on the development of HspE7. Actual results could be materially different from those implied by these forward- looking statements due to factors over which we have limited control, including but not limited to our ability to continue as a going concern, our ability to enter into corporate partnering relationships (and the effects and terms of those relationships), difficulties inherent in the manufacture of commercial-grade clinical supplies, our ability to meet regulatory approval requirements, the development of our potential products, including HspE7, not proceeding as planned, clinical trial uncertainties, the risk that, if successfully developed, HspE7 may not be commercially successful, the effect of our limited cash resources. Please refer to our filings with Canadian securities regulators for more information on these and other applicable risks. We assume no obligation and expressly disclaim any duty to update any forward-looking statement to reflect events or circumstances after the date of this news release or to reflect the occurrence of subsequent events.

Donna Slade Director, Investor Relations 6055 Lusk Boulevard San Diego, CA USA 92121 Tel: 858/202-4900 Fax: 858/450-6849 dslade@stressgen.com

Stressgen Biotechnologies Corp.

CONTACT: Donna Slade, Director, Investor Relations, 6055 Lusk Boulevard,San Diego, CA, USA, 92121, Tel: (858) 202-4900, Fax: (858) 450-6849,dslade@stressgen.com

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