AVI Announces Final Results of NEUGENE Antisense Study In Polycystic Kidney Disease Patients.

Business Editors/Health/Medical Writers

PORTLAND, Ore.--(BUSINESS WIRE)--Feb. 26, 2003

AVI BioPharma, Inc. (Nasdaq:AVII)(Nasdaq:AVIIW)(Nasdaq:AVIIZ), today announced the final results from its NEUGENE(R) antisense drug (AVI-4126) study in adult patients with autosomal dominant polycystic kidney disease (PKD).

Results reported today confirm the safety profile of AVI-4126 in adult patients with PKD and show that kidney impairment did not seem to impact the levels of the drug in the blood. This persistence of NEUGENE antisense blood levels for a prolonged period is a new observation that suggests that infrequent dosing with this agent in various clinical settings may be sufficient.

In this single-center Phase Ib clinical trial, performed at Legacy Good Samaritan Hospital in Portland, Ore., 17 patients (two groups of six and one of five) with PKD and various degrees of kidney function impairment were exposed to 10, 30 or 90 mg of AVI's proprietary NEUGENE antisense drug, given by intravenous bolus injection. Lower doses were shown to be safe before patients were exposed to the next higher dose.

Patients in the study had increasing blood levels of AVI-4126 in proportion to the dose received. The degree of kidney impairment did not seem to impact blood levels. The blood half-life (the time required for half the administered dose to be cleared from the bloodstream) of this NEUGENE drug was approximately 8 to 9 hours, similar to the duration seen in normal volunteers. Urinary clearance of circulating AVI-4126 was approximately 10 percent to11 percent per day, which is similar to the approximate 15 percent seen in normal subjects in previous studies. Substantial blood levels of AVI-4126 were measured up to 72 hours after these single doses.

No subjects were discontinued from this study due to an adverse event, nor was dose-limiting toxicity observed. As previously reported, side effects were noted as minimal and not related to the study drug. Most subjects had no change or a slight decrease in their serum creatinine, a measure of kidney function, after drug dosing. These safety and blood distribution data will be used to help design Phase II studies in PKD.

"These data further support the feasibility of NEUGENE antisense drug as safe and effective treatment for the disease," said David H. Mason, Jr., MD, senior vice president for Clinical Development and Regulatory Affairs at AVI. "What is especially encouraging is the extent to which AVI-4126 remained present in patients' blood after a single dose with no adverse events. This suggests that patients may require less-frequent dosing of antisense drug to retain amounts effective to combat the disease."

PKD is the most common genetic life-threatening disease, with an estimated 500,000 Americans suffering from it. There are currently no approved or effective medical treatments for PKD.

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 is initiating 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. It is currently in Phase II trials for restenosis and in a Phase I/II trial for cancer. AVI has completed a Phase I NEUGENE antisense study that successfully down-regulated the liver enzyme cytochrome P450 and modified drug metabolism, and a Phase I/II 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.