Altimmune Inc. on Tuesday announced that preclinical studies of a COVID-19 vaccine candidate at the University of Alabama at Birmingham (UAB) have shown positive results that appear to distinguish this candidate from others that are currently in advanced stages of clinical development.
A clinical-stage biopharmaceutical company based in Maryland, Altimmune in March announced a collaboration with UAB to test the vaccine candidate — “AdCOVID.”
The university has extensive experience in conducting clinical studies of vaccines, including participation in research sponsored by the Vaccine Evaluation and Trial Unit, part of the National Institute of Allergy and Infectious Diseases at the National Institutes of Health.
For AdCOVID, UAB conducted preclinical studies on mice, with that work ending last month.
Frances Lund, Ph.D. — UAB’s Charles H. McCauley professor, chair of the Department of Microbiology and lead investigator for the preclinical testing of AdCOVID — has said she had made the work the highest priority for her group, which included six UAB labs, all working under university COVID-19 safety protocols.
“The goal,” she explained at the time, “is to get the data to Altimmune as rapidly as possible, so they will use the information gained from the preclinical study to design their clinical trial in people.”
Unlike other vaccine candidates that are administered by an intramuscular shot, AdCOVID is administered by a single intranasal spray.
Based on UAB’s July testing, Altimmune previously announced that the vaccine candidate prompted a mouse immune response in the blood that was strong enough to neutralize the virus, as well as a potent immune response in the respiratory tract — the site where the COVID-19 virus first infects. The vaccine candidate reportedly creates an immune response against COVID-19 spike protein that helps the virus bind to a human cell to start infection.
Now, the news has gotten even better.
In the animal models at UAB, the single AdCOVID dose also resulted in a potent T-cell response at the mucus layer of the lungs, including killer CD8+ T-cells, which can recognize and kill virally infected cells. Recent reports have suggested the importance of T-cell responses for long-term protection from COVID-19, per a release from UAB.
“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,” Altimmune announced in a Tuesday press release.
“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,” the company added.
Altimmune’s announcement detailed that AdCOVID 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. Both CD4+ and CD8+ T-cells displayed phenotypes consistent with the Th1-type immune response that is important for control of viral infection, according to UAB.
In addition to potent immunogenicity after a single dose administration, the vaccine candidate is expected to show further benefits in terms of distribution and administration. Intranasal dosing provides AdCOVID with the potential to be administered rapidly and without the need for needles, syringes or trained health care personnel. Also, the expected room temperature stability of AdCOVID may allow broad distribution of the vaccine without the need for expensive cold-chain logistics, such as refrigeration or freezing.
“The property that sets AdCOVID apart is that it has been shown preclinically to induce a potent T-cell and IgA antibody response in the lungs, in addition to the systemic neutralizing antibody response induced by intramuscular vaccine candidates,” UAB’s Lund commented in a statement. “This local mucosal immune response is an important addition to the systemic immune response and has the potential to block infection and prevent transmission.”
Altimmune is currently manufacturing AdCOVID for a human Phase 1 safety and immunogenicity study, expected to begin in the fourth quarter of this year.
Sean Ross is the editor of Yellowhammer News. You can follow him on Twitter @sean_yhn
