AVANIR Highlights Late Stage Drug Candidate Neurodex-TM- at ThinkEquity Partners Growth Conference

SAN DIEGO--(BUSINESS WIRE)--Sept. 16, 2003--AVANIR Pharmaceuticals, (AMEX: AVN) will feature its lead neurology product candidate Neurodex(TM) in a presentation at ThinkEquity Partners Growth Conference in San Francisco today. Neurodex is in Phase III clinical development for the treatment of pseudobulbar affect (PBA) and in Phase II clinical development for neuropathic pain. Neurodex is a novel product utilizing the known drug dextromethorphan in a patented delivery system.

Neurodex is the first drug candidate in clinical development specifically intended to treat PBA. The condition, also know as emotional lability, is characterized by episodes of inappropriate laughing or crying. It afflicts up to a million people in the U.S. with underlying neurodegenerative diseases such as Alzheimer's, multiple sclerosis, Lou Gehrig's disease or ALS, Parkinson's, traumatic brain injury and stroke. The company completed a pivotal Phase III study in ALS patients with PBA in which Neurodex showed highly statistically significant results for its primary endpoint (p less than 0.0013) and met all secondary endpoints. AVANIR is currently enrolling multiple sclerosis patients in a final Phase III study and anticipates submitting an NDA in 2004.

"The results of our clinical trials to date suggest that Neurodex is well positioned to fit unmet market needs in the treatment of both PBA and neuropathic pain," said President and Chief Executive Officer Gerald J. Yakatan, Ph.D. "Both treatment areas are growing and physician and patient satisfaction with currently available products is modest at best."

The U.S. neuropathic pain market is expected to reach $2.5 billion by 2010, and is an ongoing treatment problem even with multiple or combination therapy. Nearly all (90-100%) of neuropathic pain patients require pharmacotherapy to manage their pain.

A Phase II clinical trial with Neurodex in diabetic neuropathic pain was completed in June 2003. Results indicated that Neurodex was well tolerated up to the highest target dose, and patients reported decreased pain intensity that was significantly different from baseline (p less than 0.0001). In addition, by Day 8, 91% of the patients reported pain relief compared to baseline, and 97% reported pain relief by Day 15. The degree of pain relief increased with duration of the study.

Neurodex is comprised of dextromethorphan (DM) and an enzyme inhibitor that significantly slows the metabolism of DM. Although DM is considered to be neuroprotective and could be useful in treating certain central nervous system disorders based on key receptor interactions, the therapeutic utility of DM alone is limited due to its rapid metabolism. By blocking the metabolism with the inhibitor, Neurodex makes it possible to maintain therapeutic levels of DM for a longer period of time with relatively small doses.

AVANIR Pharmaceuticals is a drug discovery and development company focused on the development of treatments for central nervous system disorders and inflammatory diseases. The company's first commercialized FDA-approved product, Abreva(R), is marketed in North America by GlaxoSmithKline and is the leading over-the-counter product for the treatment of cold sores. The company's lead product candidate, Neurodex(TM), is in Phase III clinical development for pseudobulbar affect and in Phase II clinical development for neuropathic pain. An internally developed small molecule, AVP 13358, is in a Phase I clinical trial for the treatment of allergy and asthma. Using its proprietary Xenerex(TM) technology, AVANIR also develops human monoclonal antibodies for infectious diseases and other therapeutic applications. Further information about AVANIR can be found at www.avanir.com.

The information contained in this press release, including any forward-looking statements contained herein, 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 like "estimate," "anticipate," "believe," "plan" or "expect." The company disclaims any intent or obligation to update these forward-looking statements. 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. If approved, Neurodex will be competing against products with presumably larger promotion budgets and sales forces.

CONTACT: AVANIR Pharmaceuticals
Patrice Saxon, 858-622-5202
psaxon@avanir.com
or
Redington Inc.
Thomas Redington, 203-222-7399
tredington@redingtoninc.com

SOURCE: AVANIR Pharmaceuticals