Feline pancreatic cancer

Business Editors/Health/Medical Writers

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PORTLAND, Ore.--(BUSINESS WIRE)--Dec. 4, 2003

AVI BioPharma, Inc. (Nasdaq:AVII), today announced promising preclinical results from its antiviral program using the company's proprietary NEUGENE(R) antisense agents to target single-stranded RNA viruses.

AVI's antisense drug targeting calicivirus was evaluated by the Greenhill Humane Society shelter in Eugene, Ore., which had been forced to close due to an outbreak of feline calicivirus. The NEUGENE drug was administered subcutaneously to infected kittens once a day for five days. Veterinarians at the shelter observed that of the 20 kittens that received the NEUGENE antisense drug, 17 survived. Of the approximately 30 kittens that were not treated, all died within 24 to 96 hours after the onset of symptoms. AVI previously reported similar positive results from a feline calicivirus outbreak in an Atlanta animal shelter.

"The results we observed in this trial are statistically significant and represent additional supportive data demonstrating the efficacy of our NEUGENE antisense technology," said Patrick L. Iversen, Ph.D., senior vice president of research and development at AVI. "Feline calicivirus is an appropriate model of human norovirus (Norwalk virus), the virus that continues to plague the cruise ship industry. These results are indicative of the broad utility of our compounds to combat single-stranded RNA viruses."

Due to the unique nature of its third-generation antisense technology, AVI is able to quickly identify and synthesize a targeted antisense drug in response to emerging viral outbreaks. Once a virus is sequenced, AVI can determine the best target to block viral replication and manufacture an antisense agent for testing within seven to 10 days.

"No other drug development technology, or other antisense technology, could respond this quickly to a viral outbreak scenario," said Denis R. Burger, Ph.D., chief executive officer at AVI. "The unique targeting characteristics of our NEUGENE antisense compounds make these response times a reality."

Calicivirus is a single-stranded RNA virus that can cause upper respiratory distress, conjunctivitis, peripheral edema and hemorrhages in infected animals, often leading to death.

About AVI BioPharma

AVI BioPharma develops therapeutic products for the treatment of life-threatening diseases using two technology platforms: third-generation NEUGENE antisense drugs and cancer immunotherapy. AVI's lead NEUGENE antisense compound is designed to target cell proliferation disorders, including cardiovascular restenosis, cancer and polycystic kidney disease. In addition to targeting specific genes in the body, AVI's antiviral program uses NEUGENE antisense compounds to target single-stranded RNA viruses, including West Nile virus, SARS coronavirus, calicivirus and hepatitis C. AVI's second technology, AVICINE(R), is a therapeutic cancer vaccine with late-stage trials planned for the treatment of pancreatic cancer. More information about AVI is available on the company's Web site at http://www.avibio.com/.

"Safe Harbor" Statement under the Private Securities Litigation Reform Act of 1995: The statements that are not historical facts contained in this release are forward-looking statements that involve risks and uncertainties, including, but not limited to, the results of research and development efforts, the results of preclinical and clinical testing, the effect of regulation by the FDA and other agencies, the impact of competitive products, product development, commercialization and technological difficulties, and other risks detailed in the company's Securities and Exchange Commission filings.