Vaxart has conducted preclinical studies to determine the immunogenic potential of VXA-RSV-f in mice and cotton rats. These studies showed that vaccination with VXA-RSV-f elicited substantial systemic serum IgG responses in test animals.
[0181] As described
The primary objective of the immunogenicity studies of the RSV vaccine candidate VXA-RSV-f was to demon-
strate that vector construct could elicit antibody responses in mice and cotton rats, and that the adaptive immune responses generated did not lead to enhanced RSV disease such as that known to occur with the formalin inactivated RSV vaccine. Further, studies were performed in animals to demonstrate the value of the adjuvant for inducing antigen specific immune enhancement.
Table 5 Nonclinical Pharmacolog
Mice (6 females/group) were immunized with VXA-RSV-f using three different routes of delivery in order to determine whether the construct was immunogenic. Animals were immunized with 1x108 IU on weeks 0 and 3 using three different routes of delivery (intranasal, intramuscular, and oral). Antibody titers to RSV were measured on week 7. Results show that both the i.n. and i.m. routes of delivery were potent at eliciting antibody responses, and that oral administration was able to elicit some immunity but was not as potent in mice as the other two routes of delivery
Lungs and nasal passages were harvested 5 days later and analyzed for the ability of the vaccines to protect against RSV replication and disease in cotton rat tissue. Immunization with the VXA- RSV-f vaccine provided complete protection against RSV replication in both lungs and the nose, whereas the formalin inactivated vaccine (FI-RSV) and adjuvant alone (Ad-Adj) groups provided no protection against
There were no serious adverse events reported in the study.
