AVI Files for Orphan Designation for its West Nile Virus Drug.

Business Editors/Health/Medical Writers

PORTLAND, Ore.--(BUSINESS WIRE)--May 14, 2003

AVI BioPharma, Inc. (Nasdaq:AVII), (Nasdaq:AVIIW), (Nasdaq:AVIIZ), today announced that it has filed an application with the Food and Drug Administration (FDA) to obtain Orphan designation for its West Nile NEUGENE(R) antisense drug, AVI-4020.

FDA grants Orphan designation to drugs developed for rare diseases. The West Nile virus epidemic, while growing, is well within the parameters for Orphan Drug designation. Achievement of Orphan designation provides for seven years of marketing exclusivity, effectively preventing a similar drug from being registered and sold for that indication.

The combination of a very wet winter throughout the United States and early warm weather has given rise to fears that the West Nile virus epidemic will grow in 2003. Severe West Nile virus infections are fatal in approximately 10 percent of affected patients, and may produce significant neurologic problems in many more patients. In 2002, approximately 4,000 cases of patients with severe West Nile virus disease (and nearly 400 deaths) were recorded in the United States by the Centers for Disease Control and Prevention (CDC). The virus infects the brain and surrounding structures and produces a variety of clinical effects, including meningitis, altered mental status, a paralysis similar to that seen with poliovirus infections, and, in the most severe cases, irreversible coma.

David H. Mason Jr., M.D., AVI's senior vice president of Clinical Development and Regulatory Affairs, said, "Orphan Drug designation is an important tool for companies that, like AVI, are often developing drugs for rare and emerging diseases. Marketing exclusivity provides an important incentive for rapidly bringing a drug through the development process."

About AVI BioPharma

AVI BioPharma develops therapeutic products for the treatment of life-threatening diseases using two technology platforms: NEUGENE antisense drugs and cancer immunotherapy. Its lead cancer agent, AVICINE(R), a therapeutic cancer vaccine, has completed three Phase II trials in colorectal and pancreatic cancer and the company plans to initiate a Phase III pivotal trial in pancreatic cancer, with a supporting study in colorectal cancer. The first application of its NEUGENE compounds, Resten-NG(TM), is designed to treat cancer, cardiovascular restenosis and other cell proliferation disorders by inhibiting the production of a cellular transcription factor, the oncogene c-myc. The company is in a Phase II trial for restenosis and in a Phase Ib trial for cancer. AVI has completed four Phase I NEUGENE antisense studies that successfully down-regulated the liver enzyme cytochrome P-450 and modified drug metabolism, and a Phase Ib trial in polycystic kidney disease. 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.