PRESS RELEASE: 12/17/2005

Kirin Pharma USA Science Announces Development of a Novel Anti-Influenza Therapeutic Preliminary Data Presented at the 45th ICAAC Meeting Demonstrates Potential Against Multiple Influenza Strains, Including Avian Influenza Strain, H5N1.

San Diego, CA, December 17, 2005- Kirin Pharma USA, Inc., a wholly-owned subsidiary of Kirin Brewery Co., Ltd., of Japan, announced today the development of a novel, fully human monoclonal antibody to the influenza A M2 protein for protection against and treatment of influenza infection.  In preliminary studies using in vitro and in vivo systems, the antibody demonstrated broad activity against a wide range of human and avian influenza strains, including the recently emerging avian influenza strain, H5N1.  Based upon these data, Kirin Pharma USA Science is now initiating pre-clinical studies required for the commencement of human clinical testing of the anti-M2 monoclonal antibody.

These data will be presented today at the 45th Interscience Conference on Chemotherapy and Antimicrobial Agents (ICAAC) Meeting in Washington, D.C.

Development and Summary of Results

Kirin Pharma USA’s fully human monoclonal antibodies to M2 were generated by immunizing the TC Mouse® with a twenty-three amino acid region (M2peptide) corresponding to the extracellular domain of the M2 protein of influenza A. This particular M2 peptide was selected for immunization because it is highly conserved among many different influenza strains, including avian flu strains, as compared to other membrane proteins that are expressed by the influenza A virus.  Based on initial in vitro studies, candidate human anti-M2 monoclonal antibodies were selected based on their ability to bind to the M2 peptide as well as to the full length M2 protein. 

In vitro studies demonstrated that the candidate antibodies bound a broad range of M2 peptide analogs that were tested, including those peptide analogs that corresponded to the M2 sequences of highly pathogenic avian influenza virus strains such as H5N1and H9N2, as well as to those epidemic influenza strains which typically occur on an annual basis such as H1N1 and H3N2. In vivo studies using mice demonstrated that Kirin Pharma USA’s anti-M2 monoclonal antibodies protected mice from a lethal challenge of influenza A virus.  Virus replication was also dramatically inhibited in the lung of these mice.

“We are very excited by the preliminary in vitro and in vivo results of Kirin Pharma USA’s fully human anti-M2 antibody, especially with respect to its potential efficacy to target a wide range of influenza viruses.  Considering the current concerns for a potential flu pandemic, new therapeutic options should be explored, and Kirin Pharma USA’s passive immunotherapy approach has the potential to address the concerns in a novel manner”, said Dr. Shinichiro Kato, Kirin Pharma USA’s Chief Scientific Officer.

Passive immunization is a widely accepted prophylactic and therapeutic approach with demonstrated efficacy in a variety of infectious diseases.  Kirin Pharma USA’s passive immunization approach using fully human antibodies to the M2 protein provides an alternative treatment and preventative strategy for influenza with potentially minimal side effects and a long duration of efficacy.  Kirin Pharma USA’s anti-M2 antibody can potentially be used not only for combating influenza pandemics, but it can also be used in those patients where vaccine coverage may not be optimal, such as the very young and the elderly.  Our preliminary results demonstrate the potential of Kirin Pharma USA’s antibody approach as a novel therapeutic for the treatment of influenza A.

A fact sheet regarding Kirin Pharma USA’s anti-influenza program is available from Kirin Pharma USA’s Business Development Department.  Please contact Maya Tanaka at 858-558-1167.