AVANIR Presents Phase II Data on Neurodex for Neuropathic Pain at the ASRA Pain Meeting

SAN DIEGO, Nov 12, 2004 (BUSINESS WIRE) -- AVANIR Pharmaceuticals (AMEX:AVN) today presented the results of a clinical study of its lead drug candidate Neurodex(TM) in patients with painful diabetic neuropathy at the 2004 annual meeting of the American Society of Regional Anesthesia and Pain Medicine (ASRA). The poster, An Open-Label Dose-Escalation Study of Dextromethorphan and Quinidine in Painful Diabetic Neuropathy, describes results demonstrating that Neurodex is well-tolerated up to the highest target dose. Additionally, patients reported decreased pain intensity that was significantly different from baseline pain (p less than 0.0001). The degree of pain relief increased with the duration of the study.

The clinical trial was conducted at five U.S. sites in 36 adult volunteers with painful diabetic neuropathy and was designed to evaluate the safety and tolerability of escalating doses of Neurodex for future clinical trials. AVANIR expects to initiate a Phase III clinical trial evaluating the safety and efficacy of Neurodex in the treatment of diabetic neuropathic pain in 2005.

Neurodex is comprised of dextromethorphan and an enzyme inhibitor that slows the rapid metabolism of dextromethorphan in the liver. Slowing the metabolism with the inhibitor makes it possible to maintain therapeutic levels for a longer period of time with relatively small doses of dextromethorphan. The NMDA receptor antagonist and sigma-1 agonist activity of Neurodex suggests utility in treating certain central nervous system disorders including neuropathic pain.

Diabetic neuropathy, caused by nerve damage as a consequence of diabetes, is a condition in which diabetics experience pain on a regular basis in their extremities. According to the American Diabetes Association, at least half of the 17 million Americans who have diabetes are estimated to suffer from diabetic neuropathic pain.

AVANIR Pharmaceuticals is a drug discovery and development company focused on treatments for chronic diseases. The Company's most advanced product candidate, Neurodex, is in Phase III clinical development for pseudobulbar affect, and in Phase II clinical development for neuropathic pain. A potential treatment for allergy and asthma, AVP 13358, is in Phase I clinical development. The Company's first commercialized product, Abreva(R), is marketed in North America by GlaxoSmithKline Consumer Healthcare 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.

AVANIR press releases and presentations, including any forward-looking statements contained therein, should be reviewed in conjunction with the Company's most recent Annual Report on Form 10-K and other publicly available information regarding the company. Copies of such information are available from the company upon request. Such publicly available information sets forth many risks and uncertainties related to the company's business and technology. Forward-looking statements often contain such words as "estimate," "anticipate," "intend," "plan" or "expect." Research findings are not always supportable by evidence obtained from subsequent clinical trials. This Phase II open label study was a non-placebo controlled trial and, therefore, will not be acceptable as one of the two clinical trials expected to be required for FDA approval. The Company can make no assurances that the Neurodex Phase III clinical trials will yield positive results. Final review decisions made by the FDA and other regulatory agencies concerning Neurodex clinical trial results are unpredictable and outside the influence and/or control of the company. AVANIR disclaims any intent or obligation to update these forward-looking statements.

SOURCE: AVANIR Pharmaceuticals

AVANIR Pharmaceuticals
Patrice Saxon, 858-622-5202 (Investor Relations)
psaxon@avanir.com