AVANIR Successfully Generates Antibody Effective At Neutralizing Key Anthrax Toxin

SAN DIEGO, Feb 11, 2003 /PRNewswire-FirstCall via COMTEX/ -- AVANIR Pharmaceuticals (Amex: AVN) announced that using its Xenerex(TM) technology it has generated a fully human antibody that successfully neutralizes the key toxin of the Class A biowarfare agent anthrax. This antibody candidate could potentially, either alone or in combination with other antibodies, provide immediate immunity to individuals who have been exposed to anthrax or who suspect they have been exposed.

"Currently there is a gap in treatment for individuals that could be or are exposed to anthrax spores," stated Gerald J. Yakatan, Ph.D., President and CEO of AVANIR Pharmaceuticals. "Because of the long immunization timeframe of the vaccine currently available, there are groups of individuals for whom vaccination against anthrax is not possible or effective and for whom alternative therapies need to be developed. Our research is aimed at developing human antibodies that can neutralize the anthrax toxin after exposure has occurred, and we have achieved an important milestone in that effort."

The Company's promising lead candidate has demonstrated both high affinity and the capability to neutralize the protective antigen (PA) anthrax toxin. AVANIR is moving forward in its preclinical development plan with the aim of eventually providing an important component in the nation's comprehensive biodefense efforts.

About Anthrax

The B. anthracis organism was one of the first biological warfare agents to be developed and continues to be a major threat in this regard. The anthrax exotoxin consists of three parts, the protective antigen (PA), the lethal factor (LF), and the edema factor (EF) toxins. The PA toxin has been the subject of most treatment efforts undertaken to date, including vaccines, because it is believed that neutralizing the PA toxin may prevent the LF and EF toxins from accessing and destroying human cells. Although vaccine strains have been developed, currently there are concerns regarding their efficacy and suitability for wide-spread use in the civilian population. The only FDA approved anthrax vaccine, BioThrax(TM), requires six injections given over 18 months, with annual booster injections recommended thereafter.

Anthrax is one of the primary targets discussed in President Bush's proposed Project BioShield, a comprehensive effort to develop and make available modern, effective countermeasures against biological and other dangerous agents announced in the recent State of the Union address. Project BioShield, a joint activity of the new Department of Homeland Security and the Department of Health and Human Services, will make available almost $6 billion to purchase new countermeasures for smallpox, anthrax, and botulinum over the next 10 years.

About the Xenerex(TM) Technology

AVANIR has developed a proprietary platform technology that is capable of generating fully human antibodies to target antigens through the engraftment of human immune system cells into immunodeficient mice. By screening and selecting cells from donors that already produce protective antibodies, the likelihood of a successful outcome is greatly increased.

The Xenerex technology is ideally suited to generating fully human antibodies to infectious diseases in general and biowarfare agents in particular. Scientists identify the specific human protective antibody- producing lymphocytes and create a recombinant antibody cell line. The monoclonal antibody product harvested from these lines provide the means of treating the disease.

A government grant from CCAT was awarded in June of 2002 to fund the initial development of the anthrax treatment. The Center for Commercialization of Advanced Technology (CCAT) is a joint project administered by the San Diego State University Foundation and the Department of Defense with the mission of providing initial funding for promising technologies in biodefense.

AVANIR intends to use its Xenerex technology to generate human antibodies to the remaining two toxins of anthrax as well as the toxins produced by C. Botulinum. In addition to the Company's biodefense effort, a commercial program is underway to generate useful fully human antibody product candidates to selected viral and bacterial organisms where unmet medical needs exist.

About the Company

AVANIR Pharmaceuticals, based in San Diego, is a drug discovery and development company with a commercialized FDA-approved product (Abreva(R)) and a product in Phase III clinical trials (Neurodex(TM)). AVANIR is engaged in small molecule research to develop treatments for central nervous system disorders and inflammatory diseases. Through the use of its Xenerex(TM) technology, AVANIR also develops human monoclonal antibodies for therapeutic applications. Further information about AVANIR can be found at www.AVANIR.com .

Conference Call and Webcast

Management will host a conference call with a simultaneous webcast on February 12, 2003 at 11:00 a.m. Pacific/ 2:00 p.m. Eastern Standard Time. The webcast will be available live via the Internet by accessing AVANIR's web site at www.AVANIR.com or CCBN's www.companyboardroom.com . Please go to either web site at least ten minutes early to register, download and install any necessary audio software. Replays of the webcast will be available for 90 days, or a phone replay will be available through February 19, 2003, by dialing 888-266-2086 or 703-925-2435 and entering the passcode 6412665.

Except for the historical information presented herein, matters discussed in this press release contain forward-looking statements that are subject to certain risks and uncertainties that could cause actual results to differ materially from any future results, performance or achievements expressed or implied by such statements. Statements that are not historical facts, including statements that are preceded by, followed by, or that include such words as "estimate," "anticipate," "believe," "plan" or "expect" or similar statements are forward-looking statements. Risks and uncertainties for AVANIR Pharmaceuticals include risks associated with product discovery and development as well as risks shown in AVANIR's most recent Annual Report on Form 10-K and Quarterly Report on Form 10-Q and from time-to-time in other publicly available information regarding the company. Copies of such information are available from AVANIR upon request. Such publicly available information sets forth many risks and uncertainties related to AVANIR's business and technology. The Xenerex(TM) monoclonal antibody technology competes with several technologies used by large pharmaceutical and biotechnology companies and is subject to a number of uncertainties, including risks associated with the success of clinical trials, the progress of research and product development programs, the regulatory approval process, competitive products and future capital requirements. There can be no assurance that such development efforts will succeed, that such products will receive required regulatory clearance, or that even if such regulatory clearance were received, that such products would ultimately achieve commercial success. The companies disclaim any intent or obligations to update these forward-looking statements.

For further information please contact: Analyst/Investor, Tricia Ross of FRB|Weber Shandwick, +1-310-407-6540, tross@webershandwick.com; or Media, Dennis Ellman of Beck Ellman Heald, +1-858-453-9600, dme@behmedia.com, both for AVANIR Pharmaceuticals; or Patrice Saxon, Investor Relations of AVANIR Pharmaceuticals, +1-858-622-5202, psaxon@AVANIR.com

SOURCE AVANIR Pharmaceuticals

CONTACT:
Analyst/Investor, Tricia Ross of FRB|Weber Shandwick,
+1-310-407-6540, tross@webershandwick.com; or Media, Dennis Ellman of Beck
Ellman Heald, +1-858-453-9600, dme@behmedia.com, both for AVANIR
Pharmaceuticals; or Patrice Saxon, Investor Relations of AVANIR
Pharmaceuticals, +1-858-622-5202, psaxon@AVANIR.com

URL:
http://www.companyboardroom.com
http://www.AVANIR.com

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