AVI Reports Positive Independent Results With NEUGENE Antisense Compound Targeting SARS.

Business Editors/Health/Medical Writers

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

AVI BioPharma, Inc. (Nasdaq:AVII), today announced positive preclinical test results from an independent laboratory evaluating the effectiveness of AVI's NEUGENE(R) antisense compound against the human coronavirus implicated in Severe Acute Respiratory Syndrome (SARS).

The study, conducted at The Scripps Research Institute (TSRI) in La Jolla, Calif., evaluated the antiviral activity of AVI's NEUGENE compound, AVI-4179, against the SARS coronavirus using three different types of cell culture analyses. In the studies, treatment with AVI-4179 protected infected cells from viral-induced cell death, limited the growth of the virus and reduced the spread of the virus in cell culture.

The results of these experiments, performed in the laboratory of Michael Buchmeier, Ph.D., a professor at TSRI, show a high potency of this antisense compound in inhibiting the SARS virus in cell culture. By comparison, this antisense approach was approximately 10 times more effective than an antibiotic previously found effective against some coronaviruses.

"We were able to quickly test AVI's drugs against the SARS virus because we were familiar with AVI's NEUGENE technology from previous collaborations on a similar virus, the murine hepatitis virus," Buchmeier said.

AVI's antiviral research program has produced antisense drugs shown to be active against a range of single-stranded RNA viruses, including West Nile virus, feline calicivirus, hepatitis C virus and murine hepatitis virus in preclinical testing. Because of their simple genetic structure, single-stranded RNA viruses have proven to be attractive targets for NEUGENE antisense drugs.

"With this outside independent corroboration of our internal positive results, we are optimistic about the potential of our technology against the SARS coronavirus," said Patrick L. Iversen, Ph.D., senior vice president of research and development at AVI. "We are collaborating with several U.S. and international laboratories, including the National Institute of Allergy and Infectious Disease (NIAID). Further independent test results should be forthcoming, although these results demonstrate to us that we have the right compound for the right target."

Antisense drugs are synthetic segments of the genetic sequence of a disease-causing organism, which recognize, lock onto and block replication of the organism. AVI's previous experience with viruses provides a platform for a possible therapeutic approach to SARS. AVI's proprietary NEUGENE antisense chemistry allows the company to rapidly respond to emerging infectious diseases, such as SARS.

About AVI BioPharma

AVI 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 cardiovascular restenosis, cancer, polycystic kidney disease and other cell proliferation disorders. 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 and colorectal cancer. More information about AVI is available on the company's Web site at http://www.avibio.com/.

About The Scripps Research Institute

TSRI is one of the world's largest, private, nonprofit biomedical research organizations. It stands at the forefront of basic biomedical science that seeks to comprehend the most fundamental processes of life. TSRI is internationally recognized for its research into immunology, molecular and cellular biology, chemistry, neurosciences, autoimmune diseases, cardiovascular diseases, and synthetic vaccine development. It is dedicated to the creation of basic knowledge in the biosciences for medical application and the betterment of human health, to the pursuit of fundamental scientific advances through interdisciplinary programs and collaborations, and to the education and training of researchers from around the world preparing to meet the scientific challenges of the future.

"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.