On Aug. 25, 2020, Altimmune announced additional positive results from the preclinical studies of its single-dose intranasal COVID-19 vaccine candidate, AdCOVID. The studies were conducted as part of Altimmune’s ongoing collaboration with the University of Alabama at Birmingham (UAB).

The latest study showed potent stimulation of antigen-specific CD4+ and CD8+ T cells in the lungs of CD-1 mice as early as 10 days following a single intranasal vaccination, with responses strongly biased toward CD8+ T cells. The mucosal T cell response in the respiratory tract is believed to be dependent on the intranasal route of administration and we believe it has the potential to provide additional protection against COVID-19.  The induction of a mucosal T cell response in the lungs has not been shown, to date, with the intramuscularly administered COVID-19 vaccine candidates that are currently in the advanced stages of clinical development. Both CD4+ and CD8+ T cells displayed phenotypes consistent with the Th1 type immune response that is important for control of viral infections. CD8+ T cells, also known as killer T cells, can recognize and kill virally infected cells, and recent clinical reports in China and Europe have suggested the importance of T-cell responses in long-term protection from COVID-19.

On July 13, the Company reported results from the initial studies at UAB that showed that AdCOVID stimulated a strong systemic neutralizing antibody response in addition to a 29-fold mucosal IgA antibody response against the spike protein in the respiratory tract. Additional data from CD-1 mice analyzed since the July 13 announcement showed mean serum neutralization titers 4-weeks after a single intranasal dose exceeded 1:400 in a foci reduction neutralization assay against wild-type SARS-CoV-2 virus. The Company is currently manufacturing AdCOVID for a Phase 1 safety and immunogenicity study expected to begin in Q4 2020.