The vaccine appears to be an answer to the logistics and storage problems that are associated with such a therapy. In the wake of the avian flu scare, the rush by governments worldwide to stockpile enough vaccines has often overtaken thoughts on how the vaccine is best handled under its optimal conditions.
The GelVac influenza vaccine uses Carrington Laboratories GelSite polymer as a platform and incorporates inactivated whole virion antigen that is prepared using a cell-based production system and an improved purification process.
The Polymer itself is extracted and purified from the Aloe vera plant and is a member of a family of carbohydrates that the US Food and Drug Administration has classified as "Generally Regarded As Safe" (GRAS).
It is water-based and capable of changing from a solid or liquid into a gel upon contact with body fluid, a process called in situ gelation, making possible the sustained release of vaccines and other pharmaceuticals over prolonged periods of time.
In coupling the vaccine with DelSite Biotechnology's GelVac nasal powder vaccine delivery system, the dry powder formulation provides several potential advantages including better stability, room temperature storage and no need for mercury or other preservatives. Nasal immunisation induces both systemic and mucosal immune responses.
"Because GelVac vaccines contain no preservatives and are stable at room temperature for prolonged periods, they can be distributed without refrigeration through regular distribution channels and can easily be stockpiled until needed," said Carlton Turner, president & CEO of >Carrington Laboratories.
"In the case of a global flu pandemic, GelVac can be rapidly shipped to ensure efficient inoculation of our population."
In addition, the vaccine comes in powder form that is easily administered and could be self-administered, if necessitated by an overwhelmed health care system.
The powder has been designed to gel on contact with nasal fluid, prolonging the nasal residence time and sustaining the antigen release potentially allowing for an enhanced protection.
Nasally administered vaccines form a first-line of immune defence for the upper respiratory system, a common entry point for influenza virus, as well as prompting the body's normal systemic immune response.
The GelVac nasal powder vaccine delivery system is DelSite's most advanced delivery platform.
In May 2005, DelSite announced results of a Phase I clinical trial involving healthy volunteers in a double-blind, crossover design that demonstrated that the GelVac system (without antigen) was safe and well tolerated, and that doses were delivered consistently and reproducibly to the nasal cavity.
Development of the GelVac influenza vaccine is partially supported by a NIH/NIAID SBIR biodefense grant and a $6m challenge grant.