AVANIR Announces Completion of Patient Enrollment for Neurodex Pivotal Phase III Trial; Pseudobulbar Affect Trial Exceeds Enrollment Goal

SAN DIEGO--(BUSINESS WIRE)--March 31, 2004--AVANIR Pharmaceuticals (AMEX:AVN) today announced that patient enrollment is complete in the Company's second pivotal Phase III clinical trial evaluating Neurodex(TM) for the treatment of pseudobulbar affect (PBA) in patients with neurological disorders. The clinical trial is being conducted in patients suffering from multiple sclerosis (MS) who also have PBA. Results of AVANIR's previous Phase III clinical study of PBA in patients with amyotrophic lateral sclerosis (ALS) were positive, with statistical significance achieved in the primary and all secondary endpoints.

"Due to an increase in interest over the past quarter our clinical trial has exceeded its patient enrollment goal," said Gerald J. Yakatan, Ph.D., President and CEO of AVANIR Pharmaceuticals. "Our clinical and regulatory team has done an outstanding job in enlisting patients while maintaining stringent enrollment standards. Upon completion of the trial, we will unblind and analyze the data and conduct a standard review for completeness and accuracy. Assuming the data are favorable, we expect to submit our new drug application (NDA) this year."

Pseudobulbar affect, a condition also known as emotional lability, affects a diverse population of patients, including those with Alzheimer's, MS, Lou Gehrig's disease or ALS, Parkinson's, and those with neuronal damage following stroke or traumatic brain injury. While the underlying neurological disorders that cause PBA vary from patient to patient, the condition manifests in inappropriate and uncontrollable emotional outbursts. IMS Health estimates the market for PBA to be $450 million by 2005. Currently, there are no approved drugs designated for the treatment of PBA.

A total of 150 patients have been enrolled in the clinical trial, which was originally designed to include 140 patients. Patients in the trial are randomized to receive either Neurodex or placebo for a 3-month treatment period. As in the first Phase III clinical trial, the primary endpoint is the change in a subject's score on the CNS-Lability Scale (CNS-LS) compared to a baseline score prior to treatment. The CNS-LS is a validated, published scale that measures the severity and frequency of a subject's episodes of emotional lability.

The double-blind clinical trial is being conducted at 19 study sites in the U.S. and four sites in Israel. A broader open-label study is also ongoing that involves patients with symptoms of PBA in conjunction with neurological disorders such as stroke, Alzheimer's disease, ALS, MS, and traumatic brain injury.

AVANIR has the exclusive license to develop, manufacture and market Neurodex(TM) for multiple potential indications including pseudobulbar affect, neuropathic pain, chronic cough and weaning drug-dependent patients from narcotics and anti-depressants.

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), is in Phase III clinical development for the treatment of pseudobulbar affect. Neurodex(TM) is also in Phase II 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. Using its proprietary Xenerex(TM) technology, AVANIR also develops human monoclonal antibodies for infectious diseases and other therapeutic applications. 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.

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 and the Company can make no assurances that the Neurodex clinical trials will yield positive results. Final review decisions made by the FDA and other regulatory agencies concerning clinical trial results are unpredictable and are not within the control of the company. The Company disclaims any intent or obligation to update these forward-looking statements.

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

SOURCE: AVANIR Pharmaceuticals