AVI BioPharma Inc. Presents Promising Data On Long-Term Impact of Antisense Inhibitor Administered Following Balloon Angioplasty.

PORTLAND, Ore.--(BW HealthWire)--Sept. 10, 1999--

Data presented at international conference shows AVI antisense 

compound, Resten-NG, inhibited excessive cell growth in blood vessel 

linings following coronary angioplasty.

AVI BioPharma, Inc. ("AVI") (Nasdaq:AVII, AVIIW) presented results from studies of Resten-NG(TM), an antisense compound being developed for the prevention of the cardiovascular disease restenosis, at the 21st Congress of the European Society of Cardiology in Barcelona, Spain.

At the conference, Patrick L. Iversen, Ph.D., senior vice president of research and development for AVI, presented the results of a study that explored the long-term impact of Resten-NG administered following angioplasty.

The results presented further confirm the feasibility of local delivery of Resten-NG into vessels at the time of balloon angioplasty to prevent restenosis. Restenosis is a frequent complication that follows angioplasty treatment for coronary artery disease, during which smooth muscle cells divide rapidly to cause closure of the artery for a second time. Local delivery of AVI's antisense compound prevented balloon-induced changes.

The study showed that local delivery of Resten-NG inhibited excessive cell growth for up to 60 days within an artery which has undergone percutaneous transluminal coronary angioplasty (PTCA). Results confirmed that Resten-NG inhibited translation of c-myc messenger RNA and reduced the expression of c-myc gene product. C-myc is expressed during cell proliferation in a wide variety of tissues. Resten-NG is AVI's gene-specific approach to halting c-myc expression, based on an antisense mechanism of action. The study was conducted in a rabbit model.

Dr. Iversen stated, "These data demonstrate the tremendous promise of Resten-NG as a therapeutic agent for use at the time of angioplasty. Observations from this study add confidence to the success observed in previous studies of the use of Resten-NG following angioplasty, conducted in three other animal models."

Denis R. Burger, Ph.D., president and chief executive officer of AVI BioPharma Inc., added, "Resten-NG is an important component of our NeuGenes(R) antisense development program and we continue to explore its ability to halt cell proliferation in a variety of other life threatening diseases including cancer."

The company expects to file an Investigational New Drug Application for Resten-NG for the treatment of restenosis later this year.

AVI BioPharma, Inc. is dedicated to the development and commercialization of products for the treatment of life-threatening diseases using three technology platforms: vaccines, gene-targeted drugs, and drug delivery. Its lead clinical agent, Avicine(TM), an essentially non-toxic cancer vaccine, will soon enter a Phase III licensing trial in colorectal cancer and a Phase II trial in prostate cancer. Further, AVI has developed a drug delivery technology called Cytoporter(TM) which has been successful in penetrating cell membranes and, as a result, may be useful in improving delivery of many FDA-approved drugs and drugs in development.

"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 pre-clinical 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.