AVI BioPharma Initiates Clinical Development Program For NeuGene Antisense Treatment of Coronary Artery Bypass Grafts

Preclinical Program Is Under Way in Strategic Relationship With Thomas Jefferson University

PORTLAND, Ore. - April 29, 2002 - AVI BioPharma, Inc., (Nasdaq: AVII, AVIIW, AVIIZ) today announced the initiation of a clinical development program using its NeuGene® antisense drug Resten-NG™ to reduce the failure rate of coronary artery bypass grafts (CABG).

Coronary artery disease leads to occlusion of the major arteries supplying blood to the heart, which can be treated by intervention or surgery using balloon angioplasty or bypass grafting. There are approximately 1 million balloon angioplasties and 550,000 bypass grafts done annually in the United States, with a significant percentage failing. Failure in both angioplasty and saphenous vein grafts is the result of injury to the vessel lining and activation of the c-myc gene. Subsequent pathology involves smooth muscle cell proliferation, secretion of collagen and expression of inflammatory mediators and adherence factors. This leads to restenosis in 20 percent or more of balloon angioplasties and a similar failure rate of saphenous vein bypass grafts.

Research studies have suggested that saphenous veins treated with antisense to the c-myc gene may improve clinical outcomes after bypass grafting. AVI and Thomas Jefferson University (Jefferson) in Philadelphia have entered into a strategic relationship to use Resten-NG, AVI's c-myc antisense drug, in saphenous vein bypass grafts in preclinical and clinical development. Preclinical studies recently began at Jefferson using Resten-NG and are expected to continue through the end of this year. The preclinical studies are being carried out under the direction of Yi Shi, M.D., Ph.D., Research Associate Professor of Medicine, Jefferson Medical College of Thomas Jefferson University, and Director of the Cardiovascular Research Center at Jefferson Heart Institute; and John D. Mannion, M.D., Associate Professor of Surgery, Jefferson. Phase I and Phase II human trials are expected to commence in 2003 under the direction of Dr. Mannion.

"More than 80 percent of all CABG procedures today use one arterial graft and two saphenous vein grafts," commented noted cardiologist and antisense pioneer Andrew Zalewski, M.D., Professor of Medicine, Jefferson. "Because the vein grafts are placed into the arterial circulation, they have a failure rate of up to 20 percent involving a mechanism similar to restenosis and triggered by expression of c-myc. We have previous experience with blocking this process with older formulations of antisense and felt that AVI's superior NeuGene chemistry holds the best chance for success. Our role at Jefferson is to complete the preclinical studies with Resten-NG and to launch carefully designed clinical trials early next year."

AVI licensed the exclusive worldwide rights to U.S. and foreign patents titled "Arteriovenous and Venous Graft Treatment: Methods and Compositions" and "Inhibition of Extracellular Matrix Synthesis by Antisense Compounds Directed to Nuclear Proto-Oncogenes" from Jefferson.

"This exciting program will become a key clinical development area for AVI. Because of our advanced stage of development of Resten-NG for coated stents with Medtronic, Inc., AVI is poised to move quickly and aggressively into the bypass graft area," stated Denis R. Burger, Ph.D., CEO of AVI. "This is a potential billion dollar market currently without an approved drug. This is the first antisense drug that we plan to take through clinical development and into commercialization on our own."

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®, a therapeutic cancer vaccine, has completed three Phase II trials in colorectal and pancreatic cancer and is in a Phase III pivotal trial in colorectal cancer. The first application of its NeuGene compounds, Resten-NG™, 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. It is currently in Phase II trials for restenosis and in Phase I/II trials for cancer and 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.