Avantogen Receives Milestone Payment from Endocyte for GPI Vaccine Adjuvant; Company Also Receives European Patent and Commences Preclinical Studies for Herpes Vaccine.

SAN DIEGO & SYDNEY, Australia -- Avantogen, Ltd. (ASX:ACU), formerly Australian Cancer Technology, today announced that Endocyte, Inc. will pay its first milestone payment to the Company for Avantogen's successful submission of a Drug Master File (DMF) to the U.S. Food and Drug Administration (FDA) for its proprietary vaccine adjuvant GPI-0100. Avantogen announced the submission of the DMF on April 7, 2005 in Australia. Endocyte is Avantogen's partner and licensee for the use of GPI-0100 in an immunotherapy for kidney cancer.

Endocyte is currently conducting a multi-center, open-label, baseline-controlled, dose-ranging Phase I clinical study of an investigational targeted immunotherapy using GPI-0100. The study is designed to evaluate the safety and pharmacokinetics of the immunotherapy regimen. Endocyte's novel targeted immunotherapy is comprised of GPI-0100 adjuvant and a folate-conjugated molecule (EC17) that targets folate receptor positive tumor cells to potentially enhance tumor cell removal by cytokine stimulated immune cells. The over-expression of the folate receptor occurs in a number of malignancies, including kidney and ovarian cancers.

"This is the first milestone payment that we've received for GPI-0100, and it validates our commercialization strategy for this exceptional adjuvant," said Leonard Firestone, MD, CEO of Avantogen. "We expect additional milestone payments from other licensees, including Pfizer Animal Health Division, in the near future. We anticipate that other companies will soon adopt GPI-0100 as their preferred vaccine adjuvant."

More GPI Adjuvant Progress

This key milestone follows the granting of European patent number 0996451 entitled "Triterpene Saponin Analogs having Adjuvant and Immunostimulatory Activity". The patent provides protection around the Company's immune-enhancing adjuvant GPI-0100 and its use as a component in vaccines and the initiation of preclinical trials for the use of GPI-0100 in a potential vaccine to the Herpes Simplex Virus (HSV-2) in European Union countries.

Additionally, Avantogen recently announced that, together with the University of Alabama at Birmingham (UAB), the Company has commenced preclinical studies using GPI-0100 as an adjuvant to increase the immune response to a new vaccine designed to reduce the recurrence and shorten the duration of herpetic lesions caused by the Herpes Simplex Virus (HSV-2). The research will be conducted at UAB under the direction of Earl R. Kern, Ph.D., Research Professor at UAB's Department of Pediatrics and a recognized expert in the area of Herpes viruses.

Adjuvants boost the physiologic response to a foreign substance by stimulating the immune system. GPI-0100, which Avantogen acquired from Galenica in 2004, is a modified, semi-synthetic saponin, a naturally occurring plant detergent or surfactant. The saponin upon which GPI-0100 is based occurs in the bark of a South American tree. GPI-0100 has been shown to stimulate both the antibody and cellular components of the immune system, and modifications made to the molecule increase its stability and safety profile versus naturally occurring saponins.

About Avantogen

Avantogen (formerly Australian Cancer Technology) is an international biotechnology company developing a broad oncology-related product portfolio. Avantogen is developing RP101, an exceptionally promising pancreatic cancer drug currently in Phase II clinical studies, through a joint venture with Bioaccelerate of New York. Avantogen's Pentrys(TM) anti-cancer vaccine is undergoing phase IIb clinical trials in prostate cancer patients, and the Company is advancing a family of immune-enhancing adjuvants which has been in three Phase I cancer trials in the United States. The company has also marketed Revisys(TM), a branded line of medical nutritionals specifically developed to address special nutritional needs, such as those following cancer treatments. Avantogen is traded on the Australian Stock Exchange (ASX) under the symbol ACU. The Company has established a Level 1 ADR stock program in the U.S. trading under the symbol AUCJY and also is listed on the Xetra exchange, the electronic trading system of the Frankfurt Stock Exchange, trading under the symbol CBS.

About Endocyte

Endocyte is an innovative biotechnology company developing a new generation of receptor-targeted therapeutics or "smart drugs" for the treatment of cancer and autoimmune diseases. Current non-targeted drugs are usually toxic to normal healthy cells causing side effects, some of which can be serious and/or fatal. These side effects can lead to suboptimal dosing in order to minimize toxicities. The company's initial development focus is on a receptor for the vitamin folic acid, which is often over-expressed in cancer cells. Animal studies have shown that drugs targeted with folic acid have less toxicity, allowing for more frequent dosing and improved efficacy. Endocyte currently has two compounds in clinical trials -- EC20, a targeted diagnostic agent that has been evaluated in phase 2 studies and EC17, a targeted immunotherapy that is currently being evaluated in phase 1 studies. Its third targeted drug, EC145, will begin Phase I testing early next year. Endocyte is committed to building value by building a rich product pipeline through its own development programs and through multiple collaborations with pharmaceutical and biotechnology companies and universities.

Forward-Looking Statements

Statements contained in this press release that are not historical information are forward-looking statements as defined within the Private Securities Litigation Reform Act of 1995. Such forward-looking statements are subject to risks and uncertainties that could cause Avantogen's ("Company") actual results to differ materially from those projected or implied. Such potential risks and uncertainties relate, but are not limited, to the results of clinical trials, product demand and market acceptance, the impact of competitive products and pricing, effectiveness and pace of current and future product development, and regulatory approval. More detailed information on these and additional factors that could affect the Company's operating and financial results are described in the Company's annual reports filed or to be filed with the Australian Stock Exchange. The Company urges all interested parties to read these reports to gain a better understanding of the many business and other risks that the Company faces. The historical results achieved by the Company are not necessarily indicative of its future prospects. The Company undertakes no obligation to publicly update or revise any forward-looking statements, whether as a result of new information, future events or otherwise.