Vaxart taking COVID-19 tablet vaccine into clinic

Vaxart may not be the first to commercialize a COVID-19 vaccine, but the firm says the ease of administration and stability of its oral tablet could provide a comprehensive and long-term solution to this global pandemic.

South San Francisco-based firm Vaxart is developing an oral vaccine – administered by tablet rather than by injection – against COVID-19, caused by the novel coronavirus (SARS-CoV-2). The firm recently announced the US Food and Drug Administration (FDA) has completed its review of an Investigational New Drug (IND) application for a Phase I clinical trial.

“The approach we’ve taken to develop oral vaccines closely mirrors how natural infections occur,” Sean Tucker, founder and chief scientific officer of Vaxart told Bioprocess Insider.

Image: iStock/TanyaJoy

“Viruses like SARS-CoV-2 enter the body through surfaces of the body with mucosal lining such as the nose and mouth. Our oral tablet vaccine candidate is designed to prevent infection by giving that mucosal lining, the body’s first line of defense, immune protection against the virus referred to as mucosal immunity. Mucosal immunity may not only prevent infection but may also prevent person-to-person transmission. Traditional injectable vaccines generally make serum antibody responses but can’t block viral transmission as effectively.”

The vaccine uses a viral vector to carry the genes for two of the SARS-CoV-2 proteins, the spike and nucleocapsid. “These two proteins comprise much of the outside of the virus and what our immune system sees, representing perfect targets for immunization. The vector then delivers both genes to the cell along with a potent adjuvant that triggers an immune response specifically to the viral proteins.

Administration and manufacturing

The tablets are coated so that once they are ingested, the coating dissolves in the intestine releasing the vaccine, he added. “This targeted approach has the potential to confer superior protection against COVID-19 due to activation of mucosal immunity.”

The oral vaccine technology platform has been tested in other clinical trials, currently ongoing. “Before COVID-19 hit, we were already developing vaccines for seasonal flu, norovirus and a universal flu vaccine. To date more than 400 individuals have received a vaccine developed from our platform. A landmark study published in The Lancet ID in January 2020, showed our flu vaccine was well tolerated in people and worked just as well as than a leading injectable flu vaccine.”

The vaccine is grown in large bioreactors. It is then extracted, purified, dried, and pressed into tablets before being packaged. The firm has already contracted Kindred Biosciences to make the candidate from its facility in Burlingame, California, but according to Tucker the firm plans to secure more capacity with third-party producers to scale up manufacturing  as the program advances in the clinic.

Not the first…

The first approved vaccines against COVID-19 could be just months away as the likes of Moderna, AstraZeneca, and Pfizer/BioNTech race to reach commercialization under unprecedented timelines. But an oral vaccine like Vaxart’s could offer more than just efficacy in the global battle against the virus said Tucker, if and when it reaches the market.

“Combatting the COVID-19 pandemic is a long-term, global effort. While we might not be the first vaccine approved for COVID-19, we believe our oral tablet vaccine candidate has the potential to provide a comprehensive and long-term solution to this global pandemic,” he told us.

“Unlike other candidates, our vaccine is a tablet taken orally and is easier to distribute in mass vaccination campaigns in large populations. It overcomes some of the logistical challenges associated with traditional injectable vaccines because it doesn’t require glass vials, needles, medical professionals or refrigeration.

“We believe that the comprehensive protection from our oral vaccine coupled with the ease of distribution could potentially help governments better achieve herd immunity in the populations they serve.”

Vaxart is not alone in looking to oral vaccines for coronavirus. Merck & Co.’s V590, based on recombinant vesicular stomatitis virus (rVSV), is being developed to be administered orally via a swish and swallow protocol. Clinical manufacturing has begun for that program, but according to Tucker Vaxart’s product remains “the only oral tablet cleared by the FDA for clinical trials, and the only one based on a platform that has been in clinical trials before.”