Aphton Announces Closing of Commercialization and Manufacturing Agreements for IGN311 With Celltrion.

PHILADELPHIA -- Aphton Corporation (NASDAQ:APHT) announced the formal completion of two agreements with Celltrion, Inc., South Korea for the licensing and commercialization and the product development and manufacturing of Aphton's clinical product candidate IGN311. IGN311, a humanized monoclonal antibody targeting the Lewis Y antigen, is being developed by Aphton's wholly-owned subsidiary, Igeneon AG, as a potential new therapy for the treatment of cancer. Lewis Y is a tumor-related antigen that is expressed in up to 90% of all epithelial cancers, including breast, colon, gastric, and pancreatic cancers.

Under the agreements, Igeneon granted Celltrion a license to commercialize IGN311 in certain Asian countries, including Japan. In return, Igeneon will receive milestone payments and royalties from Celltrion. In addition, Celltrion will provide development and manufacturing services related to the optimization and upscaling of IGN311 and will produce material for further clinical development. Celltrion will have the option to manufacture IGN311 for global commercialization.

"We are excited about the close cooperation of both companies and about the progress made in the comprehensive work program laid out in these agreements to advance the development of IGN311," commented Patrick Mooney, MD, Chairman and Chief Executive Officer of Aphton. "This deal validates the concept of our IGN311 anti-Lewis Y antibody, and it allows us to advance the development of this product candidate with a limited impact to our cash flow."

About IGN311

IGN311 is a humanized monoclonal antibody against the Lewis Y carbohydrate antigen, a blood-group-related oligosaccharide. Lewis Y is overexpressed in up to 90% of all epithelial cancers and its expression on adult normal tissues is very restricted; hence IGN311 has the potential to target a broad range of carcinomas. IGN311 is designed to exert clinical effects by destruction of tumor cells by activation of effector functions and by selective growth inhibition via functional receptors.

About Aphton

Aphton Corporation, headquartered in Philadelphia, Pennsylvania, is a clinical stage biopharmaceutical company focused on developing targeted immunotherapies for cancer. Aphton's products seek to empower the body's own immune system to fight disease. Through the acquisition of Igeneon AG in March 2005, Aphton acquired late-stage products, IGN101, a cancer vaccine designed to induce an immune response against EpCAM-positive tumor cells, as well as IGN311. Aphton has strategic alliances with Xoma for treating gastrointestinal and other gastrin-sensitive cancers using anti-gastrin monoclonal and other antibodies; and Daiichi Pure Chemicals for the development, manufacturing and commercialization of gastrin-related diagnostic kits. Aphton's most advanced product, Insegia(TM), targets the hormone, gastrin 17, in an attempt to treat gastrointestinal cancers. Aphton is currently seeking partners to support the further development of Insegia. For more information about Aphton or its programs please visit Aphton's website at http://www.aphton.com.

Safe Harbor 

This press release includes forward-looking statements within the meaning of the federal securities laws, including statements about Aphton's expectations regarding: (1) the potential benefits to Aphton resulting from the licensing and commercialization agreements, including Aphton's belief that the agreements advance the development of IGN311 and that such advancement will have very little impact on Aphton's cash flow; (2) the potential of IGN311 to target a broad range of carcinomas, destroy tumor cells, and exert clinical effects by destruction of tumor cells; (3) the Company's belief in gastrin as a viable target in treating cancer; (4) the Company's expectation regarding the purpose and effectiveness of fully-humanized monoclonal antibodies, IGN101 and IGN311, and its cancer immunotherapy, Insegia; and (5) Aphton's intent to seek partners to further support the development of Insegia. These forward-looking statements may be affected by risks and uncertainties that could cause the actual results to differ materially from those expressed in such forward-looking statements. Aphton undertakes no obligation to update forward-looking statements to reflect events or circumstances after the date hereof. This information is qualified in its entirety by cautionary statements and risk factor disclosure contained in Aphton's Securities and Exchange Commission filings, including Aphton's report on Form 10-K filed with the Commission on March 16, 2005. These risk factors include, but are not limited to: (1) the risks and uncertainties inherent in the drug development process and in Aphton's and Igeneon's business; (2) the ability of Aphton and Celltrion to successfully collaborate in the development of IGN311; (3) the timing or results of ongoing and future clinical trials for IGN311; (4) the ability of Aphton and Celltrion to obtain regulatory approval for IGN311; (5) the ability of Celltrion and any approved third parties to manufacture and supply IGN311 in commercial quantities; (6) the ability of Aphton and Celltrion to gain commercial acceptance for IGN311; (7) the ability of Aphton and Celltrion to fund the development, manufacturing and commercialization of IGN311; (8) Aphton's ability to find a partner who will support the further development of Insegia; (9) intellectual property risks; (10) the impact of competitive products and pricing; and (11) changing economic conditions.