Thursday, 25 June 2009 16:25
Novavax, Inc. (Nasdaq: NVAX) announced publication of the preclinical study results that supported the clinical development of the company's investigational VLP vaccine against the H3N2, H1N1 and B influenza strains. The study, which was conducted by scientists from the University of Pittsburgh, Center for Vaccine Research and Novavax, was published in the June 24, 2009 online issue of PLoS ONE.
The vaccine contains three VLPs mixed together in a single formulation; each made up of the hemagglutinin (HA), neuraminidase (NA) and matrix 1 (M1) proteins from the representative strains. These proteins are important for broad protection against influenza, which is responsible for nearly 200,000 hospitalizations and 36,000 deaths in the U.S. each year. The vaccine is currently in Phase 2 clinical testing.
In this study, mice and ferrets received intramuscular injections of VLP vaccine which induced HAI antibodies against all three influenza strains represented in the vaccine and against a variety of drifted strains. All of the ferrets who received a vaccine dose of 15 mcg/strain, the dose used for currently licensed vaccines, developed HAI titers greater than or equal to 1:40. This level of antibody has been shown to be important for protection against flu in human studies of influenza vaccines. In addition, approximately 50% of ferrets developed HAI titers greater than or equal to 1:40 against drifted H3N2 strains from the 1999, 2002, and 2005 influenza seasons. The vaccine was also protective, reducing the amount of influenza virus in the nose of ferrets that were challenged with the H3N2 strain from the 2005-6 season.
In addition to antibody response, the study also examined cell-mediated immunity. T cell responses in mice vaccinated with the seasonal VLP vaccine were compared with T cell responses in mice vaccinated with a commercial influenza vaccine. Of note, mice vaccinated with the VLP vaccine had higher levels of HA flu-specific CD8+ T cells than mice vaccinated with the commercial vaccine. CD8+ T cells play a role in clearing virus from the respiratory tract, which may be an important factor in preventing influenza-associated pneumonia, a leading cause of flu-related hospitalizations in adults older than 65 years of age.
"This study demonstrates the breadth of the immune response induced by the VLP vaccine," said Ted Ross, Ph.D., Assistant Professor, Center for Vaccine Research, University of Pittsburgh. "Not only did the vaccine induce robust HAI responses, it also induced HA-specific CD8+ T cell responses that were superior to those of a split vaccine. This finding may be reflective of the integrity of the structure of the HA protein presented in the VLP."
"We are pleased with the results of this study, which supported the human clinical trials of our seasonal influenza VLP vaccine," said Dr. Rahul Singhvi, president and CEO of Novavax. "We also observed robust HAI responses among subjects in the clinical trial of our seasonal flu vaccine, which we announced last December, including responses against drifted strains. We look forward to future studies to evaluate the breadth of the immune response induced by our VLP-based influenza vaccines."
Novavax, Inc. (Nasdaq: NVAX) is a clinical-stage biotechnology company creating novel vaccines, including H1N1, to address a broad range of infectious diseases worldwide using advanced proprietary virus-like-particle (VLP) technology. The company produces these VLP-based, potent, recombinant vaccines utilizing new and efficient manufacturing approaches.