Avanir Pharmaceuticals Completes Second Phase III Clinical Trial of Neurodex for Pseudobulbar Affect.

SAN DIEGO -- AVANIR Pharmaceuticals (AMEX:AVN) announced the completion of the treatment phase of a Phase III clinical trial investigating the safety and effectiveness of Neurodex(TM) in treating pseudobulbar affect in patients with multiple sclerosis (MS).

Pseudobulbar affect (PBA) is a symptom complex that is characterized by uncontrollable laughing and crying and is experienced by an estimated one million patients with neurological conditions such as ALS or Lou Gehrig's disease, Alzheimer's disease, MS, stroke and traumatic brain injury. Neurodex is the first drug product in clinical development specifically intended to treat PBA.

One hundred fifty MS patients with PBA participated in the double-blind, placebo controlled, multi-center clinical trial. To determine suitability for inclusion in the trial, patients were assessed for PBA by clinical observation and a diagnostic tool called the Center for Neurologic Study Lability Scale (CNS-LS). The CNS-LS is a validated scale (Journal of Neurology, Neurosurgery, and Psychiatry, 1997; 63: 89-93) that measures frequency and severity of PBA episodes. The primary endpoint of the study is a comparison in the mean improvement in CNS-LS scores between patients treated with Neurodex and the placebo group. Other endpoints in the study compared the number of PBA episodes, the improvement in quality of life, the improvement in quality of relationships, and changes in pain intensity. Patients in the Phase III clinical trial were treated with Neurodex or placebo on a twelve-hour dosing schedule for ninety days.

"With the completion of this trial we have achieved another major 2004 corporate objective and have moved closer to bringing Neurodex to market," said AVANIR President and Chief Executive Officer Gerald J. Yakatan, Ph.D. "If, after case report clarification and statistical analyses, data from this trial confirm the results of the first Phase III trial reported in 2002, they will be incorporated into a New Drug Application (NDA) seeking U.S. marketing approval for the treatment of PBA."

Neurodex(TM) is a patented, orally administered combination of dextromethorphan (DM) and an enzyme inhibitor, quinidine sulfate (Q), that sustains elevated levels of DM in the human body. Results of Phase I studies have demonstrated that the combination of DM, known to be a sigma-1 agonist and NMDA receptor antagonist, and low doses of Q, resulted in higher and prolonged dextromethorphan blood levels (Clinical Pharmacology & Therapeutics, 1992; 51: 647-55; 1999; 39: 984).

The first Phase III trial of Neurodex for PBA in ALS patients was completed in June 2002. This was a three-arm trial with patients randomly selected for treatment with DM alone, Q alone, or with the drug candidate Neurodex. The results of the trial for the primary endpoint and all secondary endpoints were statistically significant: adjusted mean improvement in CNS-LS for Neurodex patients compared to patients on DM alone (p=0.0013) and Q alone (p=0.0002); adjusted mean improvement in overall quality of life scores for Neurodex-treated patients compared to those on DM alone (p=0.0015) and Q alone (p=0.0013); and, adjusted mean improvement in quality of relationship scores for Neurodex patients compared to patients treated with DM alone (p less than 0.0001) and Q alone (p=0.0002).

AVANIR has the exclusive license to develop, manufacture and market Neurodex for four potential indications: pseudobulbar affect, neuropathic pain, chronic cough and weaning drug-dependent patients from narcotics and anti-depressants. There have been six U.S. patents issued for Neurodex and these indications.

AVANIR Pharmaceuticals is a drug discovery and development company focused on novel treatments for chronic diseases. The Company's most advanced product candidate, Neurodex(TM), 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, 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. Research findings are not always supportable by evidence obtained from subsequent clinical trials and the Company can make no assurances that the Neurodex Phase III clinical trial will yield positive results. Even if the Phase III clinical trial results are positive, the Company can make no assurances that the FDA will accept the company's new drug application for Neurodex or that Neurodex will ultimately be approved by the FDA. 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 obligation to update these forward-looking statements.