AVI BIOPHARMA INC. Reports Encouraging Clinical Data From Multi-Center Phase II Study of Avicine in Advanced Colorectal Cancer.

PORTLAND, Ore.--(BW HealthWire)--Dec. 10, 1998--

Patients Responding to Avicine Demonstrate Increased Survival

AVI BIOPHARMA INC. ("AVI")(Nasdaq: AVII, AVIIW) today released clinical data from a multi-center Phase II clinical trial of Avicine(tm), a therapeutic cancer vaccine, in advanced colorectal cancer. The data reflects a two-year clinical trial at 11 cancer centers throughout the United States in which two doses of Avicine were compared in 77 patients with measurable metastatic colorectal cancer. The patients were randomized to two treatment arms and evaluated to assess immunogenicity, safety and efficacy of the vaccine. Overall, patient data demonstrates a measurable immune response to human chorionic gonadotropin (hCG), increased survival in immune responders, and from a safety standpoint, essentially no toxicity.

Colorectal cancer is the third most frequent cancer type in the U.S. with approximately 131,000 diagnoses and 55,000 deaths in 1997. Approximately one in 17 Americans will develop colorectal cancer in their lifetime. Patients with advanced disease and 5-fluorouracil (5-FU) treatment failures are currently treated with Camptosar(R) (Pharmacia & Upjohn, Inc. (NYSE: PNU)) or an additional regimen of 5-FU. In this clinical setting, supporting therapy results in a median survival of approximately 28 weeks, 5-FU results in a median survival of approximately 37 weeks and Camptosar approximately 39 weeks.

Detailed analysis of the clinical data revealed that approximately two-thirds of the patients responded to the vaccine by producing antibodies to hCG, while the remaining one-third were too ill or otherwise unable to mount an immune response. Importantly, overall median survival in the group of patients responding to the vaccination was 42 weeks, compared with a median survival of 17 weeks in patients that did not produce specific antibodies. When the responding patients were evaluated further, and data segmented into high- and low-dose treatment arms, low-dose immunotherapy resulted in a median survival of 46 weeks, while the high-dose treatment group demonstrated a 39 week median survival.

Patrick L. Iversen, Ph.D., AVI's Vice President of Research and Development, commented, "It is important to note that in order to have effective vaccine therapy, patients must be able to respond immunologically over 4-8 weeks, the period it takes to mount an immune response. Patients unable to sustain an immune response cannot hope to benefit from any cancer vaccine therapy. In this regard, patients who received all doses of the vaccine over a 16-week evaluation period demonstrated median survival of 58 weeks with low-dose immunotherapy and 44 weeks with the high-dose regimen. Considering the advanced stage of cancer in these study patients, these are truly remarkable and noteworthy results."

Denis R. Burger, Ph.D., President and CEO of AVI BioPharma, stated, "Based on the data collected to date in both colorectal and pancreatic cancer, we are encouraged that Avicine has demonstrated efficacy and safety, and may provide patients with an essentially non-toxic therapy. The extensive Phase II data in advanced colorectal cancer validate our belief that hCG is an excellent cancer vaccine target. As a result, we look forward to initiating a multi-center Phase III licensing trial in 300 patients, which is expected to provide further evidence of Avicine's ability to effect patient outcome by both anti-tumor effector mechanisms and neutralizing the biological activity of tumor-associated hCG."

AVI is also planning a Phase II study comparing patients with pancreatic cancer treated with Avicine to patients treated with the combination of Avicine plus gemcitabine (Gemzar(R)) produced by Eli Lilly & Co. (NYSE: LLY); and a Phase II study treating pancreatic cancer patients with Avicine in combination with a drug in Phase III clinical trials developed by SuperGen, Inc. (Nasdaq NM: SUPG) called RFS-2000, an improved topoisomerase-I inhibitor.

Avicine, a therapeutic cancer vaccine, is AVI BioPharma's lead product candidate. Avicine elicits a highly specific immune response to the human hormone and growth factor hCG, a cancer-associated oncofetal protein. Avicine is essentially a non-toxic immunotherapy and has been evaluated in five clinical trials. To date, more than 125 cancer patients have been treated. Early studies have provided evidence of objective tumor responses and apparent survival benefits in patients who have failed conventional therapy.

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, soon will enter a Phase III licensing trial in colorectal cancer, a Phase II/III 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 NEU-GENES(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.