AVANIR's Pivotal Neurodex Clinical Trial Data Presented at American Academy of Neurology Meeting; Data on the Treatment of PBA in MS Patients Selected as a ``Highlight of the Meeting''.

SAN DIEGO -- AVANIR Pharmaceuticals (AMEX:AVN) announced that data from its Phase III clinical trial examining Neurodex(TM) in the treatment of pseudobulbar affect (PBA) in patients with multiple sclerosis (MS) were presented today at the 2005 Annual Meeting of the American Academy of Neurology (AAN) in Miami, Florida. Dr. Hillel Panitch, Professor of Neurology at the University of Vermont College of Medicine and Director of the Multiple Sclerosis Center at Fletcher Allen Health Care in Burlington, Vermont, presented the results of the trial. Additionally, a summary of the data has been selected for presentation at the AAN's "Scientific Program Highlights Plenary Session" on Friday, April 15th at 5:15 pm.

"Neurodex is the first drug designed specifically to treat PBA," reported Dr. Panitch, one of the 22 investigators who participated in the trial. "The only treatment option available to patients now is antidepressants, which can have a number of undesirable side effects. Based on the study data, patients enrolled in the trial showed improvement as early as the first week after starting treatment."

In the double-blind study, 150 MS patients with PBA were randomized to receive either placebo or Neurodex on a 12 hour dosing schedule for 90 days. In his presentation, Dr. Panitch stated that 84% of patients treated with Neurodex reported that their condition improved, compared to 49% of those given a placebo. The study participants kept a diary tracking the number of laughing/crying episodes they experienced each day. Dr. Panitch noted that Neurodex-treated patients reported 46% fewer laughing and/or crying episodes than those on placebo during the three-month trial. Neurodex-treated patients also reported overall improvement in their quality of life, quality of relationships, and in the amount of pain they experienced.

Of the side effects reported in 5% or more of the patients, a statistically significant difference between Neurodex and placebo was observed only for dizziness. In the Neurodex group, 14% of patients withdrew from therapy due to adverse events, compared to 11% discontinuing in the placebo group. The majority of reported side effects were mild to moderate in intensity.

Pseudobulbar affect is a disinhibition syndrome of the motor expression of emotion and is characterized by uncontrollable laughing or crying in a manner that is out of context to the basic social setting. PBA affects patients with neurological conditions such as ALS or Lou Gehrig's disease, Alzheimer's disease, MS, stroke and traumatic brain injury.

AVANIR is currently developing Neurodex(TM) for the treatment of two different indications, PBA and diabetic neuropathic pain. AVANIR has completed Phase III clinical testing of Neurodex for the treatment of PBA, and began submission of a new drug application (NDA) for this indication to the U.S. Food and Drug Administration (FDA) in December 2004. The submission is being done on a "rolling" basis, which allows AVANIR to submit the NDA in modules that can be evaluated by the FDA as they are submitted. The NDA will receive priority review upon completion of submission.

If approved, Neurodex would be the first drug indicated to treat PBA. In a market survey commissioned by AVANIR, IMS Health estimated the

potential market for drugs that treat PBA to be approximately $500 million in 2006, the year in which Neurodex may enter the market if approved by the FDA. Beginning in mid-2005, AVANIR intends to conduct a Phase III clinical trial for the treatment of diabetic neuropathic pain under a Special Protocol Assessment from the FDA.

AVANIR Pharmaceuticals is a drug discovery and development company focused on developing and commercializing novel therapeutic products for the treatment of chronic diseases. Our product candidates address therapeutic markets that include central nervous system and cardiovascular disorders, inflammation, and infectious disease. 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, subsequent quarterly reports on Form 10-Q 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" and actual results may differ from these forward looking statements. The Company can make no assurances regarding the timing of completion of its rolling submission of a new drug application for Neurodex(TM), whether the FDA will accept the Company's new drug application for Neurodex or whether the FDA will ultimately approve Neurodex for commercialization. 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. Even if Neurodex is approved for commercialization, the Company can make no assurances that it, or any of its marketing partners, will be able to successfully commercialize Neurodex. The Company disclaims any intent or obligation to update these forward-looking statements.