Benzinga | Mar 15, 2021 07:02AM EDT

Altimmune Announces Preclinical Data Showing Its AdCOVID COVID-19 Vaccine Candidate Showed 'Complete Protection Against Lethal Challenge and Dramatic Reduction in Viral Replication'

New Findings from Ongoing Collaborations with University of Alabama at Birmingham and Saint Louis University

Studies Show Complete Protection Against Lethal Challenge and Dramatic Reduction in Viral Replication

Systemic and Mucosal Antibody Responses Durable for at Least 6 Months Altimmune, Inc. (NASDAQ:ALT), a clinical-stage biopharmaceutical company, today announced additional preclinical data for its single dose intranasal COVID-19 vaccine candidate, AdCOVID. The preclinical studies were conducted at Altimmune's collaborating institutions, the University of Alabama at Birmingham (UAB) and Saint Louis University (SLU).

The data, which were obtained in the K18-hACE2 transgenic mouse model, showed that a single intranasal dose of AdCOVID provided 100% protection against a lethal challenge from the SARS-CoV-2 virus. In these studies, which were performed in the laboratories of James Brien Ph.D., and Amelia Pinto Ph.D., within the Department of Molecular Microbiology & Immunology at SLU, all animals that received AdCOVID survived and had no observedweight loss. Initial immunogenicity analysis showed mean antibody levels of about 1 mg/mL, suggesting that the serum IgG antibody response against the spike protein was robust, similar to what was reported in prior Company announcements. In a separate study at UAB in the laboratory of Dr. Frances Lund that was conducted in the same animal model, a single intranasal dose of AdCOVID resulted in a greater than 1000-fold reduction in replicating virus in the nasal cavity and respiratory tract following infection with SARS-CoV-2.

"These data are very promising in my view. They show that AdCOVID conferred protection not only against COVID-19 related death, but also against any clinical signs of infection in the mice," stated James Brien, Ph.D., Assistant Professor of Molecular Microbiology and Immunology at SLU.

UAB previously demonstrated that serum IgG and respiratory mucosal IgA titers in mice treated with AdCOVID were maintained for at least 6 months following a single intranasal vaccination and that memory B cells specific for spike antigen were found in the lymph nodes when assessed 5.5 months post-vaccination. Together, these new data demonstrate that a single vaccination with AdCOVID in preclinical models leads to a long-lived systemic and mucosal immune responses against the SARS-CoV-2 virus, important for sustained protection from disease.

"The data from these preclinical studies only reinforce our high expectations for the ongoing Phase 1 study of AdCOVID launched this quarter," said Dr. Bertrand Georges, Ph.D., Chief Technology Officer for Altimmune. "The complete protection observed in a stringent challenge model combined with inhibition of viral replication and persistent serum and mucosal antibody responses has not previously been demonstrated in preclinical studies for a COVID-19 vaccine candidate and supports our view of AdCOVID as a leading COVID-19 vaccine candidate."