Aphton Selects INSEGIA as Trade Name For G17DT.

MIAMI -- Aphton Corporation (Nasdaq:APHT) announced today that it has selected INSEGIA(TM) as the trade name for G17DT, Aphton's product designed to reduce tumor growth and extend survival rates of patients with gastrointestinal cancers.

"We believe the selection of the trade name marks a significant step towards the realization of Aphton as a commercial biopharmaceutical company," commented Patrick Mooney, President and CEO of Aphton. "We are excited about this milestone; with our two regulatory filings in Australia and Switzerland and expected phase III data from our clinical trial testing INSEGIA in combination with gemcitabine in patients with advanced pancreatic cancer at the end of 2004, we felt now was the perfect time to name our lead product candidate."

About INSEGIA (G17DT)

INSEGIA targets the hormone gastrin 17 to treat gastrointestinal cancers, including pancreatic, gastric, esophageal and colorectal cancer. Aphton's anti-gastrin targeted immunotherapy induces patients to produce antibodies that bind and neutralize the hormones gastrin 17 and gly-gastrin (a gastrin precursor), which are known to be involved in tumor progression in gastrointestinal (GI) cancers.

Gastrin is a key hormone in the embryological development of the gastrointestinal (GI) system. Post embryological development, most of the gastrin and gastrin receptor genes throughout the GI system are shut down. Significantly, gastrin genes are reactivated in precancerous cells and polyps and in cancer cells early in the development of its cancer. Gastrin secretion and the expression of gastrin receptors increase as the cancer progresses. Gastrin works by signaling through its receptor, the gastrin receptor (CCK-2/Gastrin-R).

In normal adult tissue, gastrin is only produced in the antrum region of the stomach and its receptor is produced only on its target cells found in the normal stomach (Parietal and ECL cells). Normally, gastrin is secreted by cells in the stomach, primarily after eating and is responsible for producing approximately 90% of the body's stomach acid.

In cancer cells, gastrin acts to signal growth and proliferation, conferring a growth advantage on them. Gastrin expression and the appearance of gastrin receptors have been associated with increasing malignant characteristics of GI tumors and with poorer prognostic outcomes. Specifically, gastrin is known to be in involved in the progression of colorectal, stomach, liver and pancreatic cancers.

Recent findings have shown that inhibiting gastrin inhibits cell growth, proliferation and metastasis, leading to programmed cell death (apoptosis). This tilts the balance, from cell growth, to cell suicide. Gastrin also stimulates the secretion and expression of other important growth factors and receptors within and on the surfaces of the cancer cells involved in tumor growth. Hence, inhibiting gastrin inhibits all of the foregoing factors that contribute to tumor growth and spread, resulting in tumor cell death. Aphton's anti-gastrin targeted immunotherapy adds a biological dimension to the treatment of gastrointestinal cancers. Gly-gastrin is also made by the tumors and like gastrin, is involved in the growth stimulation of the cancers.

About Aphton Corporation

Aphton Corporation is a biopharmaceutical company developing products using its innovative targeted immunotherapy technology for neutralizing hormones that participate in gastrointestinal system and reproductive system cancer and non-cancer diseases. Aphton has strategic alliances with Aventis Pasteur for treating gastrointestinal system and other cancers with INSEGIA in North America and Europe; GlaxoSmithKline for reproductive system cancer and non-cancer diseases worldwide; and others.

This press release includes forward looking statements, including 1) the Company's belief regarding the timing of selecting a trade name; 2) the Company's belief that the selection of a trade name marks a significant step towards the realization of the Company as a commercial biopharmaceutical company; and 3) the Company's expectations regarding the timing of data from its Phase III clinical trial testing INSEGIA in combination with gemcitabine in patients with advanced pancreatic cancer. These forward-looking statements may be affected by the risks and uncertainties inherent in the drug development process and in the Company's business. This information is qualified in its entirety by cautionary statements and risk factor disclosure contained in the Company's Securities and Exchange Commission filings, including the Company's report on Form 10-K filed with the Commission on March 15, 2004. The Company wishes to caution readers that certain important factors may have affected and could in the future affect the Company's beliefs and expectations and could cause the actual results to differ materially from those expressed in any forward-looking statement made by or on behalf of the Company. These risk factors include, but are not limited to, (1) any modifications to the data arising in connection with preparing the registration of INSEGIA; (2) our ability to obtain regulatory approval for INSEGIA or produce INSEGIA in commercial quantities and gain commercial acceptance, (3) our ability to fund the registration and commercialization of INSEGIA; (4) intellectual property risks, (5) the impact of competitive products and pricing, and (6) changing economic conditions. The Company undertakes no obligation to update forward-looking statements to reflect events or circumstances after the date hereof.