Aphton Corporation Reports Data From Clinical Trial of Insegia in Comb

Aphton Corporation Reports Data From Clinical Trial of Insegia in Combination With Chemotherapy in Pancreatic Cancer

    Business Editors/Health/Medical Writers

    PHILADELPHIA--(BUSINESS WIRE)--May 16, 2005--

Statistically Significant Difference in Survival for Patients With the Highest Antibody Response
    Aphton Corporation (NASDAQ:APHT) announced today that final data from a double-blind, placebo-controlled Phase III clinical trial of Insegia (G17DT immunogen) in combination with Gemzar (gemcitabine; Lilly) in patients with solid tumors was presented at the 2005 Annual Meeting of the American Society for Clinical Oncology (ASCO) in Orlando, Florida.
    The trial was a randomized, double-blind, placebo-controlled study in previously untreated patients with locally advanced, recurrent or metastatic pancreatic cancer. Patients were randomly assigned to receive Insegia plus gemcitabine or gemcitabine plus placebo. The study accrued 383 patients from XX medical centers on a multinational basis. The primary endpoint of this study was overall survival. Secondary endpoints included overall tumor response, time to tumor progression and an evaluation of survival by antibody response levels.
    Results of the study showed no statistically significant difference in overall survival, tumor response or time to tumor progression. However, in the study approximately 75% of patients achieved an antibody response to treatment with Insegia. An evaluation of survival by antibody response showed that patients who achieved the highest levels (16U) demonstrated a statistically significant difference in survival relative to the control group. The differences in survival were seen across covariate factors such as stage of disease and performance status.

Insegia + Gem Placebo + Gem P value N=1 N=184 Overall Survival 178 201 0.10 Overall Response 21% 23% 0.84 Time to Progression 118 days 118 days 0.09 Survival by 1.2 U (N=131) 223 d 0.47 Antibody 4 U (N=108) 246 d 201 d 0.19 Response 8 U (N=87) 250 d 0.09 16 U (N=74) 264 d 0.03

    "While we are disappointed that the primary endpoint in this study was missed, we believe that the antibody response data from this trial supports the consistent results we have seen in this population in prior clinical studies. We believe that the survival data for antibody responders demonstrate that neutralizing gastrin should impart a survival benefit," commented Patrick Mooney, M.D., Chairman and Chief Executive Officer of Aphton. "While we have decided not to pursue pancreatic cancer as a primary indication we believe that Insegia is a potential therapeutic option for patients with gastric cancer and we will look to partner the drug in this indication."

    About Insegia

    Insegia (G17DT immunogen) targets the hormone gastrin 17 in an attempt to treat gastrointestinal cancers. Studies have shown that Aphton's Insegia can induce 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.
    Experimental studies have shown that inhibiting gastrin inhibits cell growth, proliferation and metastasis, leading to programmed cell death, or apoptosis. 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. Therefore, it is believed that inhibiting gastrin may inhibit the factors that contribute to tumor growth and spread.

    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, and IGN311, a fully humanized antibody against the Lewis Y antigen. Aphton is currently seeking partners that will support the further development of Insegia (G17DT immunogen), its immunogen targeting the hormone gastrin. Aphton has strategic alliances with sanofi-aventis for the development and commercialization of Insegia related to cancers of the gastrointestinal system and other cancers in North America and Europe; Daiichi Pure Chemicals for the development, manufacturing and commercialization of gastrin-related diagnostic kits; and Xoma for developing humanized monoclonal and other antibodies to treat gastrointestinal and other gastrin-sensitive cancers. For more information about Aphton or its programs please visit Aphton's website at http://www.aphton.com.

    Safe Harbor

    Except for the factual information herein, the matters discussed herein are forward-looking statements that involve a number of risks and uncertainties and are not a guarantee of future performance. These forward-looking statements may be affected by the risks and uncertainties inherent in the drug development process and in Aphton's business. These forward statements include statements about: (1) Aphton's belief that targeting the hormone Gastrin 17 can successfully treat gastrointestinal cancers; and (2) Insegia's ability to treat gastrointestinal cancers by targeting Gastrin 17; (3) Aphton's intention to seek and ability to find a partner for Insegia. 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. Aphton wishes to caution readers that certain important factors may have affected and could in the future affect Aphton'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 Aphton. 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) Aphton's ability to obtain regulatory approval for Insegia or produce Insegia in commercial quantities and gain commercial acceptance, (3) Aphton's 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. Aphton undertakes no obligation to update forward-looking statements to reflect events or circumstances after the date hereof.

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CONTACT: For Aphton Corporation, Philadelphia TS Communications Group, LLC Tara Spiess, 215-218-4371 ir@aphton.com

KEYWORD: PENNSYLVANIA AUSTRIA INTERNATIONAL EUROPE INDUSTRY KEYWORD: PHARMACEUTICAL BIOTECHNOLOGY PRODUCT SOURCE: Aphton Corporation

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