GelVac™ / GelSite®
GelVac™ Nasal Influenza Vaccine is based on a novel plant polysaccharide (GelSite® polymer) and its gelling property to encapsulate vaccine/adjuvant formulation as gel particles that may potentially (1) enhance the immune response, (2) reduce the antigen and/or adjuvant dose, and/or (3) eliminate the boosting dose through a combination of several factors including sustained antigen release, improved antigen uptake, and improved antigen stability. Nanotherapeutics plans to conduct a Phase I safety and immunogenicity study of a GelVac™ nasal powder H5N1 influenza vaccine that possesses distinct potential advantages in meeting the critical needs of pandemic preparedness.
The vaccine consists of the GelVac™ nasal powder formulation in combination with an inactivated cell-based influenza H5N1 whole virion antigen (A/Vietnam/1203/2004). The powder vaccine formulation is filled into a positive pressure nasal delivery device and delivered into the nasal cavity by compressed air. GelSite® polymer has been tested in various vaccine formulations for administration by the nasal route and injection, including an in-situ gelling nasal powder influenza vaccine which is entering Phase 1 clinical studies. GelSite® polymer has been shown to have an adjuvant-like effect - increasing immune response and antigen sparing when administered together with the antigen by intramuscular injection. GelSite® polymer is inert and the polymer gel does not support cell adhesion. The adjuvant effect is most likely due to the sustained release by in-situ gelation at the injection site. This adjuvant effect can be obtained at a very low polymer concentration, lower than that of the alum adjuvant commonly used in licensed vaccines.
GelSite® polymer is a chemically and functionally distinct high molecular weight anionic polysaccharide (sodium polygalacturonate, CAS RN 119758-46-2) extracted from Aloe vera L., a succulent plant widely cultivated in the tropical and subtropical regions. It belongs to the pectin class of the plant polysaccharides and is general considered as safe (GRAS). GelSite® polymer possesses distinctive chemical and functional properties. It is characterized by a high galacturonic acid (Gal UA) content of >90%, an exceptionally low DM (degree of methylation) of <10%, and a high molecular weight of > 400 kDa (weight average). A combination of these chemical properties has not been described previously for a pectic substance. GelSite® polymer is manufactured under cGMP at a kilogram scale with a purity > 99%. A type IV Master File has been filed with CDER and CBER of the FDA. Nanotherapeutics also provides GelSite® and GelVac™ research, development, and manufacturing services under contract to third parties.