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San Francisco, CA, United States

Vaxart Inc. | Date: 2010-09-15

The invention provides chimeric viral expression vectors and method of use for providing an immune response against H1N1 influenza. The compositions of the invention can be used as vaccines for H1N1 strains. Advantages include rapid development and availability once a strain is isolated, and effective oral or mucosal administration.

Vaxart Inc. | Date: 2012-06-25

The present invention provides chimeric adenoviral vectors and methods for using the vectors to elicit an immune response to an antigen of interest.

Agency: Department of Health and Human Services | Branch: | Program: SBIR | Phase: Phase II | Award Amount: 2.78M | Year: 2009

DESCRIPTION (provided by applicant): The goal of this research proposal is to further develop a potent oral vaccine platform that is reusable for different pathogens and can be manufactured more rapidly and at lower cost than currently available vaccine technology. Rapid production time and ease of distribution of a vaccine in pill form will provide for an effective countermeasure against influenza and other potential pandemic viruses. Studies funded by Vaxart's Phase 1 SBIR have demonstrated that an expressed Toll Receptor 3 ligand, given in conjunction with antigen expressed from a non-replicating adenovirus vector significantly augments the adaptive immune response to oral vaccination, and is protective against avian influenza challenge in large animals. An effective gene-based technology must overcome the major obstacles of pre-existing and vaccine-induced immunity to the vector if it is to be used as a general platform for multiple antigens or boosting. Our results demonstrate that the oral vaccine route effectively circumvents vaccine induced immunity problems that occur with injected vector vaccines, which will allow the vector backbone to be reused without loss of activity. In Phase II, we propose to further develop and test vaccine effectiveness, formulation and safety in preparation for clinical testing. In Aim 1 of this proposal we will test the effectiveness of our oral vaccine to protect against cross-clade avian influenza challenge. Aim 2 provides a formulation path for oral drug product development. Aim 3 validates an animal model for pre-clinical safety testing for an enterically delivered oral vaccine. Aims 4 and 5 test for the biodistribution pattern and safety profile of oral vaccine capsule administration in animals. Together, the results from these aims will provide the pre-clinical data required to begin clinical testing of Vaxart's oral avian flu vaccine. PUBLIC HEALTH RELEVANCE: Vaxart is developing a new oral vaccination technology, which can be used to rapidly develop and manufacture effective vaccines for use against emerging pathogens including new strains of influenza virus; the technology can shorten the time from identified influenza strain to released product from 7 months to 4 months. With our flexible oral vaccine technology, genes from any pathogen can be rapidly inserted into this vaccine backbone, and manufactured into a vaccine using a highly efficient, standardized, GMP process. In addition, a significant advantage to developing a vaccine in pill form is the ease of administration in emergency situations such as pandemic, and in regions of the world that lack sufficient medical personnel.

Agency: Department of Health and Human Services | Branch: | Program: SBIR | Phase: Phase I | Award Amount: 340.50K | Year: 2008

DESCRIPTION (provided by applicant): The goal of this research proposal is to develop a potent and safe vaccine for protection against Venezuelan Equine Encephalitis (VEE). Several attenuated VEE strains have been generated for the purpose of creating a prophylactic vaccine, including a strain called TC-83 which has been licensed for use in horses. However, these attenuated strains have either proven to be too dangerous to use in humans or have a difficult regulatory approval process in front of them bef ore they will reach the market due to the neuraltropism of the VEE virus. In contrast, using a safer and well-characterized viral vector to deliver the key antigens of VEE does not have these same regulatory issues. Published experiments have demonstrate d that a recombinant adenovirus expressing the E2, E3, and 6K genes (E2E36K) of TC-83 can afford protection against aerosolized VEE in animal models. The problem is simply efficiency; the amount of recombinant adenovirus necessary for protection is prohib itively large to be effect in humans. Using West Coast Biological's patent pending technology, preliminary studies in this proposal demonstrate an expressed Toll Receptor 3 ligand, given in conjunction with antigen expressed from a non-replicating adenovi rus vector significantly augments the adaptive immune response, and can improve antibody responses to the transgene by two orders of magnitude. The proposed Aims tests whether the combination of the VEE antigen with WCB's expressed TLR3 vector can sufficie ntly and practically improve immunogenicity and protection against VEE. Aim 1 of this proposal strives to determine whether expressing TLR3 ligand and E2E36K antigen in an adenoviral vector can improve antibody responses to VEE over standard rAd expressin g the E2E36K antigen. Aim 2 determines whether the route of delivery of the expressed TLR3 ligand vector can improve systemic and mucosal immune responses, and whether pre-existing immunity to adenovirus can be circumvented by use of mucosal routes of deli very. Aim 3 investigates the ability of the expressed TLR3 ligand vector with E2E36K antigen to protect against virulent Trinidad Donkey strain VEE and other more heterologous strains. For all of these aims, we will measure antibody responses in mice usin g ELISA based assays. Together, these aims will map the development plan to commercialize the vaccine. PUBLIC HEALTH RELEVANCE - PROJECT NARRATIVE: West Coast Biologicals (WCB) is developing a new vaccine to prevent infection of Venezuelan Equine Encephalitis (VEE), a pathogen that has a high incidence of accidental laboratory exposure and that has been explored as a biowarfare agent in the past. Because of the dangers involved with some of the previous vaccine strains, WCB has made a safer vector, based upon our patent pending technology, and will explore the ability of our research vector to protect against VEE in well-characterized animal models.

Scallan C.D.,Vaxart Inc. | Tingley D.W.,Vaxart Inc. | Lindbloom J.D.,Vaxart Inc. | Toomey J.S.,Southern Research Institute | Tucker S.N.,Vaxart Inc.
Clinical and Vaccine Immunology | Year: 2013

An oral gene-based avian influenza vaccine would allow rapid development and simplified distribution, but efficacy has previously been difficult to achieve by the oral route. This study assessed protection against avian influenza virus challenge using a chimeric adenovirus vector expressing hemagglutinin and a double-stranded RNA adjuvant. Immunized ferrets and mice were protected upon lethal challenge. Further, ferrets immunized by the peroral route induced cross-clade neutralizing antibodies, and the antibodies were selective against hemagglutinin, not the vector. Similarly, experiments in mice demonstrated selective immune responses against HA with peroral delivery and the ability to circumvent preexisting vector immunity. Copyright © 2013, American Society for Microbiology. All Rights Reserved. Source

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