AVI BioPharma Announces Positive Results in NEUGENE Antisense Studies With Collaborators Targeting Emerging Viral Diseases.

PORTLAND, Ore. -- Presentations Include Ebola, Influenza, Dengue, SARS Coronavirus and Bunyavirus Studies at the International Conference on Antiviral Research

AVI BioPharma, Inc. (Nasdaq:AVII), today announced the release of extensive data in five presentations on its NEUGENE(R) antisense approach to developing antiviral therapeutics. The presentations will be given at the 18th International Conference on Antiviral Research, in Barcelona, Spain, being held April 10-14.

Two studies have been selected for plenary oral presentations. The first presentation, titled "Development of a Phosphorodiamidate Morpholino Oligomer Antisense to Ebola Zaire," highlights experiments performed in the laboratory of Sina Bavari, Ph.D., at the U.S. Army Medical Research Institute of Infectious Diseases (USAMRIID). The study is part of AVI's ongoing research in biodefense with the Chemical and Biological Defense Program of the Office of the Secretary of Defense. The presentation will be given by Patrick L. Iversen, Ph.D., senior vice president of research and development of AVI.

"Our studies in collaboration with scientists at USAMRIID on NEUGENE antisense inhibition of Ebola virus have been extensive and highly successful," Iversen said. "We have established that our antisense drug candidates are efficacious in protecting multiple animal species from lethal challenges from this aggressive pathogen. These results speak to the robust nature of our NEUGENE antisense technology and represent both an exciting alternative to current antiviral drug therapies and a real possibility of treating heretofore untreatable ailments."

The second presentation, titled "Inhibition, Escape and Attenuation of SARS Coronavirus Treated With Antisense Morpholino Oligomers," will be given by Benjamin W. Neuman, Ph.D., and Michael J. Buchmeier, Ph.D., of The Scripps Research Institute (TSRI), La Jolla, Calif. These studies, undertaken in collaboration with scientists at TSRI and AVI, demonstrate that AVI's NEUGENE antisense drug candidates reduced all three parameters of viral infection, including cytopathic effect, viral titer and viral spread. In addition, one antisense candidate was found to be particularly effective at reducing viral titer to undetectable levels, while another that was designed to affect the same target of a related virus reduced viral titer by ten thousandfold in mice.

In addition to the two plenary oral presentations, three of AVI's scientific reports have been selected for poster presentation. The first, titled "Inhibition of Influenza A Virus in Vero Cell Culture With Morpholino Oligomers," is drawn from a collaborative study with Qing Ge, Ph.D., and Jianzu Chen, Ph.D., of the Massachusetts Institute of Technology, Cambridge, Mass. In this study, NEUGENE antisense agents targeting influenza A strain H1N1 exhibited up to one thousandfold reduction in viral titer in infected cells, with excellent conservation in sequence across other influenza viruses, including H5N1, also known as avian flu. This suggests that a single antisense agent could be developed targeting both influenza A and avian influenza strains.

The second poster presentation, titled "Inhibition of Dengue Virus Serotypes 1 to 4 in Vero Cell Cultures With Morpholino Oligomers," is the result of a collaborative study with Richard Kinney, Ph.D., and colleagues at the Centers for Disease Control and Prevention facility in Fort Collins, Colo. In this study, NEUGENE antisense compounds were found to be highly efficacious in cell culture, reducing viral activity up to one millionfold and, most important, inhibiting all four serotypes of the dengue virus.

The third poster presentation, titled "Antisense Morpholino-Oligomers Directed Against Bunyavirus Genome Segments Inhibit Replication and Proliferation," is the result of collaboration with Ramon Flick, Ph.D., and colleagues at the University of Texas Medical Branch, in Galveston, and at the Institute Pasteur, Paris, France. There are more than 60 members of the Bunyavirus family that can cause severe disease in humans and livestock. Several of these viruses are on the bioterrorism Category A list, classified as those that are easily disseminated and highly contagious and that can induce a high rate of mortality. The current studies investigated NEUGENE antisense candidates for Rift Valley fever, Crimean-Congo hemorrhagic fever and Uukuniemi virus. Antisense agents were highly effective at inhibiting transcription as well as translation of the virus.

"The studies presented at this international conference demonstrate the robust nature of our extensive program to develop antiviral drugs for diseases caused by infection with RNA viruses," said Denis R. Burger, Ph.D., chief executive officer of AVI. "Our antiviral program includes ongoing human clinical trials in West Nile virus infection and preclinical studies in hepatitis C virus. We believe our technology is well-suited for use as a rapid response to bioterrorism threats and emerging viral diseases. In addition, we believe that the promising results obtained in collaboration with USAMRIID on Ebola and other viruses may be applicable to developing drug candidates to treat hemorrhagic diseases such as the recently identified Ebola-related strain of Marburg virus that is responsible for a current disease outbreak in Angola."

About AVI BioPharma

AVI BioPharma develops therapeutic products for the treatment of life-threatening diseases using third-generation NEUGENE antisense drugs. 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 combat disease by targeting single-stranded RNA viruses, including West Nile virus, hepatitis C virus, dengue virus and Ebola virus. 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.