AVANIR Enrolls First Patient in Confirmatory Phase III Trial of Zenvia(TM) in PBA

ALISO VIEJO, Calif., December 10, 2007 - AVANIR Pharmaceuticals (NASDAQ:AVNR) today announced that it has initiated enrollment of patients in the STAR (Safety, Tolerability and Efficacy Results of AVP-923 in PBA) trial, a confirmatory Phase III trial of Zenvia (dextromethorphan/quinidine [DM/Q]) in patients with pseudobulbar affect (PBA). The randomized, multi-center, international STAR trial will compare active treatment with Zenvia 30/10 mg (DM/Q) and Zenvia 20/10 mg (DM/Q) to placebo during a three-month, double-blinded phase, followed by a three-month, open-label extension study. The STAR trial is being conducted under a Special Protocol Assessment (SPA) from the U.S. Food and Drug Administration (FDA).

"We are pleased to initiate the STAR trial on schedule, which keeps us on track to complete patient enrollment within the next 15 to 18 months and report top-line data in the second half of calendar 2009," said Randall Kaye, MD, Chief Medical Officer of AVANIR. "We believe this single confirmatory Phase III STAR trial, in addition to certain pre-clinical studies already underway, will be sufficient to provide a complete response to the FDA's October 2006 approvable letter for Zenvia in the treatment of PBA."

"PBA represents an area of high unmet medical need. Currently, no FDA-approved treatment is available for the more than one million patients in the United States estimated to suffer from involuntary crying or laughing episodes of PBA," said Daniel Wynn, MD, Director, Clinical Research, Co-Director, Consultants in Neurology Multiple Sclerosis Center, Northbrook, Illinois and STAR Trial Steering Committee member. "If approved, we expect that Zenvia could considerably reduce the distress caused by PBA for those individuals and their caregivers."

About the STAR Trial

The STAR trial will enroll 270 multiple sclerosis (MS) or amyotrophic lateral sclerosis (ALS) patients who exhibit signs and symptoms of PBA at approximately 50 sites in the U.S., Canada and Latin America. The primary efficacy analysis will be based on the changes in crying/laughing episode rates recorded in patient diaries. Secondary endpoints for this clinical trial include: 1) Center for Neurologic Study-Lability Scale (CNS-LS) score; 2) Neuropsychiatric Inventory Questionnaire (NPI-Q); 3) SF-36 Health Survey; 4) Beck Depression Inventory (BDI-II); and 5) Pain Rating Scale score (MS patients only). Safety and tolerability of Zenvia will be determined by reporting adverse events, physical exam, vital signs, electrocardiogram, respiratory function tests and clinical assessment of clinical laboratory variables. For more information visit www.pbatrial.com.

About Zenvia

Zenvia is a combination of two well-characterized compounds: the therapeutically active ingredient dextromethorphan and the enzyme inhibitor quinidine, which serves to increase the bioavailability of dextromethorphan. This first-in-class drug candidate is believed to help regulate excitatory neurotransmission in two ways: through pre-synaptic inhibition of glutamate release via sigma-1 receptor agonist activity and through postsynaptic glutamate response modulation via uncompetitive, low-affinity NMDA antagonist activity. Zenvia is currently in development for the treatment of pseudobulbar affect (PBA) and diabetic peripheral neuropathic (DPN) pain. In October 2006, the Company received an approvable letter for the treatment of Zenvia in PBA. The Company has initiated a confirmatory Phase III study under a Special Protocol Assessment (SPA) agreement with the FDA utilizing a new lower quinidine dose formulation of Zenvia to address safety concerns raised in the Agency's approvable letter for Zenvia in the treatment of PBA. For more information about the Agency's SPA process see http://www.fda.gov/cder/guidance/3764fnl.htm. In April 2007 AVANIR announced successfully meeting all primary endpoints in the Phase III study of Zenvia in DPN pain. The Company is conducting a formal PK study to assess alternative lower-dose quinidine formulations of Zenvia for DPN pain that are intended to deliver similar efficacy and improved safety/tolerability versus the formulations previously tested for this indication.

About PBA

Pseudobulbar affect (PBA), also known as involuntary emotional expression disorder (IEED) and emotional lability, is a neurologic disorder that occurs secondary to neurologic disease or brain injury causing sudden and unpredictable episodes of crying, laughing, or other emotional displays. PBA is estimated to impact more than 1 million people in the United States with underlying neurologic conditions such as multiple sclerosis (MS), amyotrophic lateral sclerosis (ALS), Parkinson's disease, dementias including Alzheimer's disease, stroke, and traumatic brain injury. PBA episodes may occur when disease or injury damages the area of the brain that controls normal expression of emotion. This damage can disrupt brain signaling causing a "short circuit" and triggering involuntary PBA episodes. PBA has been shown to impair the lives of patients in both social and occupational settings. There are currently no FDA approved treatments for PBA.

About AVANIR

AVANIR Pharmaceuticals is focused on developing, acquiring and commercializing novel therapeutic products for the treatment of chronic diseases. AVANIR's products and product candidates address therapeutic markets that include the central nervous system (CNS), inflammation and infectious diseases. AVANIR's lead product candidate, Zenvia, is being developed for the treatment of PBA and is the subject of an approvable letter from the U.S. Food and Drug Administration for that indication. The Company has initiated a confirmatory Phase III study under a Special Protocol Assessment (SPA) agreement with the FDA utilizing a new lower quinidine dose formulation of Zenvia to address safety concerns raised in the Agency's approvable letter for Zenvia in the treatment of PBA. Additionally, in April 2007 AVANIR announced meeting all primary endpoints in a Phase III clinical trial with Zenvia in patients with DPN pain. The Company is conducting a formal PK study to assess alternative lower-dose quinidine formulations of Zenvia for DPN pain that are intended to deliver similar efficacy and improved safety/tolerability versus the formulations previously tested for this indication. AVANIR has also licensed a compound to Novartis International Pharmaceuticals Ltd. for the treatment of inflammatory disease. AVANIR's infectious disease drug candidate, AVP-21D9, is a human monoclonal antibody in pre-clinical development for the treatment of anthrax with funding provided to date from NIH/NIAID grants. The Company's first commercialized product, Abreva®, 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.

Forward Looking Statements

Statements in this press release that are not historical facts, including statements that are preceded by, followed by, or that include such words as "estimate,""intend,""anticipate,""believe,""plan,""goal,""expect," or similar statements, are forward-looking statements that are subject to certain risks and uncertainties that could cause actual results to differ materially from the future results expressed or implied by such statements. There can be no assurance that the proceeds received by the Company from the recent sale of the Company's FazaClo® operations, together with the Company's other available funds, will be sufficient to fund the Company's operations as currently anticipated, or that the Company will be able to commence and complete planned clinical trials within the projected time periods. There can also be no assurance that any additional Phase III trial for Zenvia will be successful, that any new doses of Zenvia will be safe and effective, or that the FDA will approve Zenvia for any indication. Risks and uncertainties affecting the Company's financial condition and operations also include the risks set forth in AVANIR's most recent Annual Report on Form 10-K and subsequent Quarterly Reports on Form 10-Q, and from time-to-time in other publicly available information regarding the Company. Copies of this information are available from AVANIR upon request. AVANIR disclaims any intent to update these forward-looking statements.

To be included on AVANIR's e-mail alert list; visit AVANIR's website or click on the link below:

http://www.b2i.us/irpass.asp?BzID=958&to=ea&s=0

Lippert/Heilshorn & Associates, Inc.
Jody Cain (jcain@lhai.com)
Brandi Floberg (bfloberg@lhai.com)
310-691-7100  
Dec 10, 2007