Avanir Presents Data on Novel Anti-Inflammatory Compounds at American Physiological Society Meeting.

SAN DIEGO -- Avanir Pharmaceuticals (AMEX:AVN) presented preclinical data on its anti-inflammatory compounds at the American Physiological Society's Conference on Immunological and Pathophysiological Mechanisms in Inflammatory Bowel Disease held in Snowmass, Colo. September 8-11, 2004. Avanir's small molecules target macrophage migration inhibitory factor (MIF), a pro-inflammatory cytokine that plays a critical role in disorders such as rheumatoid arthritis, psoriasis, and inflammatory bowel disease.

"We believe our compounds are the first examples of small molecule MIF inhibitors that show activity in animal models of inflammatory bowel disease," stated Jagadish Sircar, Ph.D., Vice President of Drug Discovery at Avanir Pharmaceuticals. "The data provide a rationale for further development of these compounds and support our hypothesis that MIF inhibition may have therapeutic value in the treatment of inflammatory disease."

In animal models of colitis, a type of inflammatory bowel disease, Avanir's compounds were effective in both preventing the progression of colitis and in reducing the signs and symptoms of ongoing colitis. Additionally, the administration of the MIF inhibitors was associated with a dose dependent reduction of well-known endogenous inflammatory mediators such as TNFa.

Avanir Pharmaceuticals is a drug discovery and development company focused on the development of treatments for chronic diseases. The Company's lead product candidate, Neurodex(TM), recently completed a second pivotal Phase III trial for the treatment of pseudobulbar affect. Neurodex(TM) is also in Phase III clinical development for the treatment of neuropathic pain. An internally developed small molecule, AVP-13358, is in a Phase I clinical trial for the treatment of allergy and asthma. The Company's first commercialized product, Abreva(R), is marketed in North America by GlaxoSmithKline and is the leading over-the-counter product for the treatment of cold sores. Further information about Avanir can be found at www.avanir.com.

Except for the historical information presented herein, matters discussed in this press release contain forward-looking statements that are subject to certain risks and uncertainties that could cause actual results to differ materially from any future results, performance or achievements expressed or implied by such statements. Statements that are not historical facts, including statements that are preceded by, followed by, or that include such words as "estimate," "anticipate," "believe," "plan" or "expect" or similar statements are forward-looking statements. Risks and uncertainties for Avanir Pharmaceuticals include risks associated with product discovery and development as well as risks shown in Avanir's most recent Annual Report on Form 10-K and Quarterly Report on Form 10-Q and from time-to-time in other publicly available information regarding the company. Copies of such information are available from Avanir upon request. Such publicly available information sets forth many risks and uncertainties related to Avanir's business and technology. Our anti-inflammation research program is in the early stages of development and competes with other research approaches and compounds under development by large pharmaceutical and biotechnology companies. Preclinical research findings are not always supportable by evidence obtained from clinical trials. Final review decisions made by the FDA and other regulatory agencies concerning clinical trial results are unpredictable and outside the influence and/or control of the Company. The company disclaims any intent or obligations to update these forward-looking statements.