Study Shows AVI BioPharma's Antisense Drug Prevents Balloon Angioplasty-induced Restenosis.

Health/Medical Writers

PORTLAND, Ore.--(BW HealthWire)--March 13, 2000

Results of this study will be presented today at a national cardiology conference. A second collaborative study, which also demonstrates the

effectiveness of AVI's NeuGenes, will be presented tomorrow.

AVI BioPharma (Nasdaq:AVII) (Nasdaq:AVIIW) (Nasdaq:AVIIZ) today will present data on the Company's antisense compound, Resten-NG at the annual American Academy of Cardiology conference being held in Anaheim, California.

Data from the collaborative studies, conducted by Patrick L. Iversen, Ph.D., AVI's senior vice president of Research and Development, and Nicholas Kipshidze, M.D., at Lenox Hill Hospital, New York, revealed that Resten-NG prevented balloon-induced restenosis in rabbits with atherosclerotic vascular disease resulting from a high-cholesterol diet.

The studies involved catheter delivery of Resten-NG, a proprietary NeuGene(R) antisense compound, designed to inhibit restenosis, the blockage of a coronary artery following balloon angioplasty. The presentation is titled, "Intravascular Delivery of Neutrally Charged Antisense Phosphorodiamidate Compound-Resten-NG Inhibits Myointimal Hyperplasia Following Balloon Angioplasty."

Dr. Iversen noted, "This study was a rigorous challenge for Resten-NG, and it demonstrated 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 conducted at Columbia University and the University of Nebraska Medical Center by outside collaborators as well as researchers from Lenox Hill Hospital and AVI."

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 initiate Phase II human clinical trials with Resten-NG later this year."

An additional collaboration with Thomas Porter, M.D., and researchers at the University of Nebraska, showed Resten-NG prevented restenosis in pigs, when delivered intravenously while bound to microbubbles, a delivery technique owned by AVI. This is important supportive preclinical data as it indicates that Resten-NG is effective in multiple species with diverse delivery methods. This presentation was titled, "Preventing Intimal Hyperplasia Following Balloon Injury in Pigs Treated with Intravenous Antisense Bound to Perfluorocarbon Albumin Microbubbles."

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 percent to 40 percent 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.

Resten-NG targets the genetic sequence c-myc, a gene responsible for initiating cell replication. Extensive preclinical studies of the compound in treating restenosis have shown highly significant preservation of vessel passageways and prevention of arterial wall thickening. Delivering Resten-NG to the site of angioplasty blocks the growth and proliferation events in the vessel walls. Approximately 1.2 million balloon angioplasty procedures are performed each year with a market exceeding $1 billion annually. AVI BioPharma develops therapeutic products for the treatment of life-threatening diseases using two technology platforms: cancer immunotherapy and gene-targeted drugs. Its lead clinical agent, AVICINE, a therapeutic cancer vaccine, is undergoing a Phase II trial in pancreatic cancer, and will soon enter a Phase III pivotal trial in colorectal cancer and a Phase II trial in prostate 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 I trials for restenosis. More information about AVI is available on the Company's website at http://www.avibio.com.

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