AVI BioPharma Presents Data in a Collaborative Study of Antisense Compound Resten-NG in Restenosis.

PORTLAND, Ore.--(BW HealthWire)--Feb. 19, 1999--AVI BIOPHARMA INC. ("AVI")(Nasdaq: AVII, AVIIW) today presented data of the company's antisense compound, Resten-NG, in collaborative preclinical study conducted by Patrick L. Iversen, Ph.D., AVI's Senior Vice President of Research and Development, and Nicholas Kipshidze, Ph.D., of the Medical College of Wisconsin. The studies involved the local delivery of Resten-NG, a proprietary phosphorodiamidate morpholino antisense compound, designed to inhibit restenosis, the blockage of a coronary artery following balloon angioplasty. Microscopic examination revealed that Resten-NG prevented balloon-induced restenosis in rabbits with atherosclerotic vascular disease resulting from a high-cholesterol diet.

Dr. Iversen noted, "This study was a rigorous challenge for Resten-NG, which was designed to investigate three therapeutic characteristics: reduction of vascular cell proliferation; inhibition of vascular wall remodeling; and prevention of thrombus formation. The results indicate highly significant preservation of vessel passageways and prevention of wall thickening following catheter delivery of Resten-NG. These observations build upon previous animal studies of Resten-NG's efficacy, which have included rat models conducted at Columbia University and at AVI BioPharma, and pig models examined at the University of Nebraska Medical Center."

Denis R. Burger, Ph.D., President and CEO of AVI BioPharma, stated, "It is certainly exciting to see that Resten-NG is continuing to show efficacy in a variety of animal models. With this promising data in hand, AVI intends to complete GMP manufacturing and GLP pre-clinical pharmacology and toxicology studies by the end of the second quarter of 1999."

When a patient has a blocked coronary artery, a procedure called balloon angioplasty is frequently used to remove the blockage. During this process, smooth muscle cells underlying the blockage may be damaged, resulting in a proliferative wound healing reaction, which can lead to closure of the artery for a second time. Restenosis occurs after approximately 20%-40% of such procedures and cannot be predicted from patient to patient. Although there are a few new clinical approaches that attempt to prevent restenosis, none is very effective, and all have significant risks associated with them. There are approximately 500,000 balloon angioplasties done in the U.S. each year with a market estimated at more than $1 billion annually.

AVI BioPharma Inc. is dedicated to the development and commercialization of products for the treatment of life-threatening diseases using three platforms: immunotherapy for cancer, gene-targeted drugs, and intracellular drug delivery technology. Its lead clinical agent, Avicine(TM), an essentially non-toxic cancer vaccine, is about to enroll patients for a Phase III licensing trial in colorectal cancer, a Phase II trial in pancreatic cancer and a Phase II trial in prostate cancer. The Company has also developed a patented class of gene-targeted drugs, called NeuGenes(R), which may be useful in the treatment of a wide range of human diseases including cardiovascular restenosis and cancer. Further, AVI has developed a novel drug delivery technology, called CytoPorter(TM), that may be useful in significantly improving drug uptake while minimizing toxicity for a wide range of FDA approved drugs.

"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.