AVI BioPharma NeuGene Antisense Drugs Suppress Influenza A Virus

Data Presented at the American Society of Microbiology 44th Interscience Conference On Antimicrobial Agents and Chemotherapy

PORTLAND, Ore. — Oct. 29, 2004 — AVI BioPharma, Inc. (Nasdaq: AVII), announced today that Qing Ge, Ph.D., of the Massachusetts Institute of Technology (MIT) Center for Cancer Research, presented data characterizing the effect of AVI’s NeuGene® drugs when applied to the influenza virus in cell culture. Study results were presented at the American Society of Microbiology’s Interscience Conference on Antimicrobial Agents and Chemotherapy in Washington, D.C.

A product of collaborative research by investigators at AVI BioPharma and MIT, Dr. Ge’s presentation was titled "Inhibition of Influenza A Virus in Cell Culture with Morpholino Oligomers."

Dr. Ge’s studies showed that several NeuGene antisense compounds each reduced the amount of influenza virus in infected cells in culture from 100- to 1,000-fold in a dose-responsive and sequence-specific manner over the two-day period of observation. In addition, some combinations of two NeuGeneS had a greater antiviral effect than a single NeuGene, generating a synergistic effect of viral suppression.

"The concern over events related to this year’s influenza vaccine shortage certainly emphasizes the need for an effective influenza therapeutic," said Denis Burger, Ph.D., chief executive officer of AVI BioPharma. "We now have several effective NeuGene compounds for further evaluation and development for use in treating influenza virus infection."

About Influenza

Influenza A causes from 3 million to 5 million cases of severe illness and as many as 500,000 deaths each year worldwide. Vaccines against matched influenza strains can prevent illness in 60% to 80% of healthy adults, but the protection is lower in high-risk groups. In the United States, even with the relatively high rate of vaccination, influenza causes more than 100,000 hospitalizations and 30,000 deaths yearly. The therapeutic limitations of current drugs, the uncertainties of vaccine development from year to year and the serious threat to public health indicate the current unmet medical need for the development of new treatments for influenza.

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, hepatitis C virus and dengue virus. AVI’s second technology, Avicine®, 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.