Press Release

For Immediate Release

BOTHELL, WA — February 4, 2010 — AVI BioPharma, Inc. (NASDAQ: AVII), a developer of RNA-based drugs, today announced that the results and scientific findings of Good Laboratory Practice (GLP)-compliant safety pharmacology and genotoxicity evaluations of AVI-4658, a drug candidate being developed by AVI for the treatment of Duchenne Muscular Dystrophy (DMD), were published online in the International Journal of Toxicology. The publication, "Safety Pharmacology and Genotoxicity Evaluation of AVI-4658," reports that the GLP-compliant preclinical studies revealed no study related effects on health status, even when dosed at the maximum feasible dose, and there were no reports of injection site reactions. It was also reported that the genotoxicity evaluation of AVI-4658 revealed no genotoxic potential, even at very high concentrations. These results suggest AVI-4658 may have a wide therapeutic window for chronic dosing and supported the initiation of the Phase 1b/2 clinical trial of AVI-4658 that is ongoing in the United Kingdom.

About Duchenne Muscular Dystrophy

DMD is one of the most common fatal genetic disorders to affect children around the world. Approximately one in every 3,500 boys worldwide is afflicted with DMD with 20,000 new cases reported each year. It is a devastating and incurable muscle-wasting disease associated with specific inborn errors in the gene that codes for dystrophin, a protein that plays a key structural role in muscle fiber function. Symptoms usually appear in male children by age three. Progressive muscle weakness of the legs and pelvis eventually spreads to the arms, neck, and other areas. By age 10, braces may be required for walking, and most patients are confined to a wheelchair by age 12. Eventually, this progresses to complete paralysis and increasing difficulty in breathing requiring ventilatory support. The condition is terminal and death usually occurs before the age of 30. The outpatient cost of care for a non-ambulatory DMD boy is among the highest of any disease. There is currently no cure for DMD, but for the first time ever, there are promising therapies in or moving into development.

About AVI BioPharma

AVI BioPharma is focused on the discovery and development of RNA-based drugs utilizing proprietary derivatives of its antisense chemistry (morpholino-modified phosphorodiamidate oligomers or PMOs) that can be applied to a wide range of diseases and genetic disorders through several distinct mechanisms of action. Unlike other RNA therapeutic approaches, AVI’s antisense technology has been used to directly target both messenger RNA (mRNA) and its precursor (pre-mRNA), allowing for both up- and down-regulation of targeted genes and proteins. AVI’s RNA-based drug programs are being evaluated for the treatment of Duchenne muscular dystrophy, including an ongoing systemic Phase 1b/2 clinical trial of exon skipping with AVI-4658. AVI’s antiviral programs have demonstrated promising outcomes in Ebola Zaire and Marburg Musoke virus infections and may prove applicable to other viral targets such as Junín, influenza, HCV or Dengue viruses. For more information, visit www.avibio.com.