In a new study, researchers announced positive results from the preclinical studies of its intranasal COVID-19 vaccine candidate, AdCOVID.
The team showed strong serum neutralizing activity and potent mucosal IgA immunity in the respiratory tract.
The induction of IgA antibody in the respiratory tract may be necessary to block both infection and transmission of the virus to prevent further spread of COVID-19.
Based on these findings, AdCOVID is expected to be advanced to a Phase 1 safety and immunogenicity study in Q4 of this year.
The research was conducted by Altimmune, Inc., a clinical-stage biopharmaceutical company and the University of Alabama at Birmingham.
AdCOVID is designed to express the receptor-binding domain of the SARS-CoV-2 virus spike protein, a key immune target that is essential for the virus to bind to cells and initiate infection.
By focusing the immune response to this portion of the viral spike protein, AdCOVID elicited a strong systemic antibody response against the receptor-binding domain in mice, achieving serum IgG antibody concentrations greater than 800 micrograms per milliliter just 14 days after administration of a single intranasal dose.
In addition, AdCOVID stimulated serum viral neutralization titers of 1:320 by Day 28, two-times higher than the titer recommended by the U.S. Food and Drug Administration for investigational convalescent plasma as a treatment for severe COVID-19.
In a separate study with UAB, a single intranasal dose of AdCOVID stimulated a 29-fold induction of mucosal IgA in bronchoalveolar fluid of vaccinated mice.
This level of IgA antibody stimulation is well above that associated with protection from disease in clinical studies of other mucosal vaccines.
The team says the potent stimulation of mucosal IgA immunity in the respiratory tract may be crucial to effectively block infection and transmission of the SARS-CoV-2 virus, given that the nasal cavity is a key point of entry and replication for the SARS-CoV-2 virus.
Intranasal dosing provides AdCOVID with the potential to be administered rapidly and without the need for needles, syringes or trained healthcare personnel.
In addition, AdCOVID’s expected room temperature stability profile may allow for broad distribution of the vaccine without the need for expensive cold-chain logistics, such as refrigeration or freezing.
One researcher of the study is Frances Lund, Ph.D., lead UAB investigator.
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