Vaccine Info

Vaxart COVID-19 Oral Vaccine

Authored by
Staff
Last reviewed
March 10, 2021

Vaxart COVID-19 Oral Vaccine (VXA-CoV2-1) Description

Vaxart announced the initiation of a program to develop an oral vaccine VXA-CoV2-1 targeting the novel coronavirus SARS-CoV-2 that causes COVID-19.

VXA-CoV2-1 triggers mucosal immune responses in humans. Mucosal immunity is believed to be the first defense against airborne viruses, such as coronavirus and flu. It may also be important in reducing viral shedding and preventing transmission.

Additionally, VXA-CoV2-1 targets both the spike protein (S) and nucleoprotein (N). The N protein is more conserved (less prone to mutations) than the S protein, and therefore new viral variants may be less likely to escape protection. The N protein is also a good target for T-cell responses. Potent T-cell responses alone may offer multi-variant protection against severe COVID-19 illness.

Vaxart announced it is also advancing S-only vaccine candidates targeted specifically against variant strains, including targeting the South African viral strain. These new candidates are expected to generate strong mucosal and serum antibody responses and complement the potent T-cell inducer VXA-CoV2-1. Vaxart has previously shown that a bivalent oral vaccine using its platform can induce immune responses without interference.

Vaxart oral recombinant vaccines are formulated as tablets that are enterically coated for efficient delivery to the small bowel. The enteric coating protects the active ingredient from the stomach's acidic environment. By targeting the small bowel, the vaccines engage the gut's finely-tuned immune system to generate broad systemic and mucosal immune responses for robust, persistent immunity.

Vaxart is currently developing a liquid formulation for young children and adults who cannot ingest tablets. Vaxart vaccines do not contain whole killed or attenuated viruses. No eggs are used in the production process.

Vaxart’s oral vaccines represent a significant advance in vaccination technology. They are designed to generate broad and durable immune responses, including mucosal and systemic responses. The oral administration route provides a more efficient and convenient administration method relative to injectable vaccines.

Vaxart COVID-19 Oral Vaccine (VXA-CoV2-1) History

On May 20, 2020, Sean Tucker, Ph.D., chief scientific officer of Vaxart, announced, “In a phase 2 efficacy study, we have demonstrated that our oral H1 flu tablet vaccine protected against influenza infection after just 1-dose. Based on these results, we believe our vaccines are ideal for protecting against mucosal respiratory viruses such as SARS-CoV-2, the virus that causes COVID-19.”

“The results of our recently published influenza challenge study demonstrated that our oral tablet vaccine primarily protects through mucosal immunity, a potential key factor when targeting mucosal pathogens, such as this new coronavirus,” said Sean Tucker, Ph.D. chief scientific officer of Vaxart.

This was a Phase 2 Randomized, Placebo- and Active-Controlled, Human Influenza A/California/04/2009 (H1N1) Challenge Study Following Administration of an Oral H1N1 HA Adenoviral-Vector Based Seasonal Influenza Vaccine and dsRNA Adjuvant (VXA-A1.1) to Healthy Adult Volunteers, which was last updated on July 26, 2018.

On August 6, 2020, Andrei Floroiu, chief executive officer of Vaxart, stated: “We believe the convenience of our oral tablet, coupled with the potential for better protection than that of injectable vaccines due to the activation of mucosal immunity, positions our COVID-19 vaccine as one of the most promising candidates for successful mass vaccination campaigns, both here in the US and abroad.”

On September 6, 2020, the non-peer-reviewed study 'Pre-clinical studies of a recombinant adenoviral mucosal vaccine to prevent SARS-CoV-2 infection' was published. These researchers stated: 'We demonstrate that, compared to the expression of the S1 domain or a stabilized spike antigen, the full length, wild-type spike antigen induces significantly higher neutralizing antibodies in the periphery and the lungs, when the vaccine is administered mucosally. This leading vaccine candidate induced Antigen-specific CD4+ and CD8+ T cells at low and high doses. This full-length spike antigen plus nucleocapsid adenovirus construct has been prioritized for further clinical development.'

On October 14, 2020 - Vaxart announced the topline results from its Hamster Challenge Study that all hamsters that received (2) oral doses of COVID-19 vaccine candidate showed no systemic weight loss, a key indicator of protection against COVID-19 in this animal model. The study evaluated Vaxart’s recombinant adenoviral vaccine, with doses given at 0 and 4 weeks. Animals were challenged with SARS-CoV-2 at week 8.

These topline data demonstrated that all unvaccinated animals lost at least 8% of their body weight, and all showed evidence of lung disease as measured by relative weight gain in the lungs. By contrast, all animals vaccinated with 2-doses of the oral vaccine maintained or gained body weight by the end of the experiment, a statistically significant result (p<0.001).

Additionally, these animals were protected against the lung weight gain seen in the unvaccinated animals (p<0.001).

On February 3, 2021, Sean Tucker, Ph.D., Vaxart’s Chief Scientific Officer, stated in a press release, “Viral variants with altered S proteins are becoming established in the population before the majority of people can be vaccinated. To end the pandemic, the world needs a vaccine that can provide long-lasting protection from emerging strains."

“T-cells can provide long-lasting cross-reactive protection against current and emerging strains of the virus. Our vaccine induced a high percentage of responding CD8+ T cells against both Spike (S) and Nucleoprotein (N) proteins, which may protect against variants with alterations in the faster-changing S protein. We expect that our vaccine will be less impacted by new variants than injectable vaccines,” Dr. Tucker added.

“Recently, we have seen the emergence of new SARS-CoV-2 strains, against which some of the leading injectable vaccines offer reduced protection. At the same time, it has become clear that mass vaccinations by needle take a long time, and new strains may emerge faster than many countries’ medical and governmental infrastructure can inject their populations. A better solution is needed given that COVID-19 may be a challenge for years to come,” said Andrei Floroiu, CEO of Vaxart, on February 25, 2021, in a press release.

“As a result of our scientists’ foresight to include both the S and N proteins, VXA-CoV2-1 could be protective against these newly emerging variant strains. We are very excited about the prospect of moving into Phase 2 not only as an oral COVID-19 vaccine candidate but one with a differentiated mechanism, which could prove to be valued globally in the fight against coronavirus.”

Vaxart is primarily focused on developing oral recombinant protein vaccines based on its proprietary oral vaccine platform. This development effort is based on the oral vaccine platform, VAAST, which employs a modular approach using a replication-incompetent adenovirus type 5 (Ad5) vector that delivers two payloads to the cells the mucosal epithelium of the small bowel. One payload is the gene coding for the selected pathogen-specific protein antigen. The other payload, which is always co-delivered, is the gene coding for the Toll-Like Receptor-3 (TLR-3) agonist, an adjuvant that activates the innate immune system and is selected for its ability to stimulate broad immune responses. Every vaccine contains the TLR-3 adjuvant component. Reviews of Vaxart’s approach to tablet vaccine delivery.

For more information, visit www.vaxart.com. (Nasdaq: VXRT)

Vaxart COVID-19 Oral Vaccine (VXA-CoV2-1) Indication

This COVID-19 Oral vaccine candidate tablet is indicated to prevent the new SARS-CoV-2 coronavirus, which causes COVID-19 disease in humans.

In preclinical testing, all animals that received one of the Vaxart vaccines had IgG anti-SARS CoV-2 antibodies in serum two weeks after the first vaccination. Antibody responses in all vaccinated groups were statistically significant compared to the untreated controls. 

Vaxart plans to select one or more vaccine candidates for cGMP manufacturing and clinical testing based on the magnitude and the breadth of the immune response. Vaxart’s oral recombinant vaccine candidate is based on its proprietary VAAST™ platform.

Vaxart COVID-19 Oral Vaccine (VXA-CoV2-1) News

March 9, 2021 - Vaxart, Inc. announced that management would present at the H.C. Wainwright Global Life Sciences Conference on March 9-10, 2021. The presentation will be available on-demand through the H.C. Wainwright conference portal available here, starting at 7 a.m. ET on Tuesday, March 9, 2021, and on Vaxart’s website after the conference.

February 25, 2021 - Vaxart, Inc. announced that it plans to initiate the first Phase 2 study of its oral COVID-19 vaccine candidate, VXA-CoV2-1, in 2Q 2021. Vaxart is also advancing S-only vaccine candidates targeted specifically against variant strains, including targeting the South African viral strain.

February 3, 2021 - California-based Vaxart, Inc. announced preliminary data from its Phase 1 study of VXA-CoV2-1 showing that its oral COVID-19 tablet vaccine candidate was generally well-tolerated and immunogenic as measured by multiple markers of an immune response to SARS-CoV-2 antigens. VXA-CoV2-1 triggered multiple immune responses against SARS-CoV-2 antigens, including CD8+ cytotoxic T-cell response to the viral Spike (S) protein, necessary for long-lasting cross-reactive immunity, higher than we have seen in any previous Vaxart clinical trial;  An increase in plasmablast cell number and an upregulation of the mucosal homing receptor, indicating activation of B cells that will home to the mucosa; An increase in pro-inflammatory Th1 cytokines, responsible for orchestrating the immune response to viral infection; IgA responses in serum and/or nasal swab samples in 100% of 2 dose subjects; neutralizing antibodies were not detected in serum and IgG responses were not seen in most subjects.

January 26, 2021 - Vaxart, Inc., announced additional results from its SARS-CoV-2 Hamster Challenge Study, as well as a peer-reviewed publication in Nature Medicine resulting from a collaboration with prominent Stanford University scientists on COVID-19 vaccine candidates. “The latest data from the SARS-CoV-2 Hamster Challenge Study reinforces our belief that our oral COVID-19 vaccine candidate shows great promise,” said Andrei Floroiu, chief executive officer of Vaxart. “Our oral vaccine could help fight the COVID-19 epidemic globally because it is stable at room temperature making it easier to transport, store, and administer than injectables. It may also appeal to those uncomfortable with injections.”

December 11, 2020 - Vaxart Inc.’s more than 2,000% rally this year on the promise of an oral Covid-19 vaccine has left the bears betting against it in rough waters. And time will tell if short-sellers get a reprieve with clinical data due next month on how well Vaxart’s pill works. “Most of us associate vaccines with needles,” said Andrei Floroiu, the biotech company’s chief executive officer. “An oral vaccine would be the holy grail.”

November 19, 2020 - Vaxart posted its corporate presentation.

November 12, 2020 - Vaxart, Inc., announced additional results from its Hamster Challenge Study: Significant reduction in lung viral load of 4-5 logs in hamsters that received two oral vaccine doses, as compared to non-vaccinated animals; Potent induction of antibody response, with serum IgG antibody titers above 10,000 in hamsters that received two oral vaccine doses. Oral vaccination protected and intranasal vaccination against intranasal challenge concerning key indicators: protection from weight loss, protection from an increase in lung weight, viral load reduction, and induction of serum IgG antibodies, demonstrating that mucosal protection by both routes of administration was comparable.

October 17, 2020 - Hagens Berman announces that it has filed a class-action lawsuit against Vaxart, Inc. and certain senior executives and updates investors. The class action, filed in the United States District Court for the Northern District of California, Case No. 3:20-cv-05949-VC, is brought on behalf of investors who purchased or otherwise acquired securities between June 25, 2020, and July 25, 2020.

October 14, 2020 - Vaxart, Inc. announced the topline results from its Hamster Challenge Study. “Our oral vaccine showed that 100% of hamsters receiving two oral doses of vaccine in the study were protected against systemic weight loss, as well as lung weight gain, which is a key indicator of lung damage due to infection,” said Sean Tucker, Ph.D., chief scientific officer, and founder of Vaxart. “Given that the hamster is a great model for assessing severe infection, this study helps to validate our vaccine’s potential to provide potent protection against COVID-19. These results increase our confidence as we move our vaccine candidate into human clinical trials.”

October 13, 2020 - Vaxart announced that the first subject had been dosed in its Phase 1 study of VXA-CoV2-1, an oral tablet COVID-19 vaccine candidate. Phase 1, an open-label, dose-ranging trial (NCT04563702), is designed to examine the safety and immunogenicity of two doses of VXA-CoV2-1 in up to 48 healthy adults volunteers aged 18 to 54 years old. Enrollment is expected to be completed by early November 2020, with participants receiving the low or high dose of the VXA-CoV2-1 oral tablet on days 1 and 29. Safety, reactogenicity, and immunogenicity assessments will be performed at set times during the active phase.

October 13, 2020 - Vaxart's recent SEC filing disclosed that 'in July 2020, Vaxart was served with a Grand Jury Subpoena from the U.S. District Court for the Northern District of California, in connection with an investigation by the Office of the U.S. Attorney for the Northern District of California (“U.S. Attorney’s Office”). The Company has provided documents called for by the subpoena, which broadly pertain to the Company’s participation in, and disclosure of, an Operation Warp Speed (“OWS”)-funded nonhuman primate study, and option grants, warrant transactions, and other corporate and financing matters disclosed since March 2020. We cooperate with the U.S. Attorney’s Office regarding these requests and have provided documents and information in response. And, in August 2020, the Enforcement Division of the Commission requested that the Company provide, voluntarily, a variety of documents that broadly pertain to the same subject matters of the documents provided to the U.S. Attorney’s Office and related matters. The Company has voluntarily provided documents requested by the SEC and is cooperating with this informal inquiry.'

September 14, 2020 - Vaxart announced that the U.S. FDA had completed its review of the Company’s Investigational New Drug application for its Phase 1 clinical trial evaluating its oral COVID-19 vaccine candidate. 

September 8, 2020 - Vaxart, Inc. announced pre-publication of a manuscript titled “Preclinical studies of a recombinant adenoviral mucosal vaccine to prevent SARS-CoV-2 infection.” Andrei Floroiu, chief executive officer of Vaxart, stated: “Cold storage distribution and the need for medical personnel as well as having to travel to vaccination sites and dislike of needles pose significant barriers to the vaccine uptake required for successful mass vaccination campaigns. We believe our room temperature stable, easy to administer oral vaccine provides a unique solution that overcomes these important difficulties."

September 3, 2020 - Vaxart, Inc. announced senior management will participate in conferences during September and invites investors to participate by webcast.

August 10, 2020 - Vaxart announced that its COVID-19 Investigational New Drug application had been filed with the U.S. FDA.

August 6, 2020 - Vaxart, Inc. provided an update on its financials for the second quarter of 2020 and a corporate update.

July 14, 2020 - Some experts say a vaccine puffed in the nose would be better at protecting people from infection.

June 26, 2020 - Vaxart, Inc. announced that its oral COVID-19 vaccine has been selected to participate in a non-human primate challenge study, organized and funded by Operation Warp Speed, a new national program to provide substantial quantities of safe, effective vaccines for Americans by January 2021.

May 20, 2020 - Sean Tucker, Ph.D., chief scientific officer of Vaxart, said: “In a phase 2 efficacy study that was recently published in the Lancet Infectious Diseases, we have demonstrated that our oral H1 flu tablet vaccine protected against influenza infection after just one dose. Based on these results, we believe our vaccines are ideal for protecting against mucosal respiratory viruses such as SARS-CoV-2, the virus that causes COVID-19.”

May 20, 2020 - Kindred Biosciences, Inc. announced it has agreed with Vaxart, Inc. to manufacture Vaxart’s oral vaccine candidate for COVID-19.  KindredBio will produce the candidate vaccine bulk drug substance under Good Manufacturing Practices and provide it to Vaxart to be formulated into a vaccine tablet to be taken by mouth instead of by needle injection. KindredBio will manufacture the vaccine for clinical trials beginning in the second half of 2020.

May 14, 2020 - Coronavirus vaccine taken by tablet instead of injection is about to go into human trials.

May 12, 2020 - Vaxart, Inc. provided a corporate update. “In January, we pivoted to COVID-19, and we are now on track to start the first Phase 1 study in the second half of this year with our oral tablet vaccine,” said Wouter Latour, MD, chief executive officer of Vaxart. “We are developing a state-of-the-art gene-based vaccine utilizing our proprietary vector platform, and the lead candidate vaccines performed well in preclinical testing, generating very high levels of antibodies.”

April 21, 2020 - Vaxart announced that it had obtained positive pre-clinical results for its COVID-19 vaccine candidates, with several of the vaccine candidates generating immune responses in all tested animals after a single dose.

March 18, 2020 - Vaxart announced that it has agreed with Emergent BioSolutions Inc. Emergent will deploy its molecule-to-market contract development and manufacturing services to help develop and manufacture Vaxart’s experimental oral vaccine candidate for coronavirus disease-19 (COVID-19). 

January 31, 2020 - Vaxart, Inc. announced today that it had initiated a program to develop a coronavirus vaccine candidate based on its proprietary oral vaccine platform, VAAST. 

September 1, 2015 - Study: High-titer neutralizing antibodies to influenza after oral tablet immunization: a phase 1, randomized, placebo-controlled trial.

2014 - Vaxart, Inc. announced clinical results demonstrating that its H1N1 tablet vaccine generates protective immunity comparable to currently licensed influenza vaccines, as measured by hemagglutinin inhibition assay (HAI), the established correlate of protection. Vaxart’s founder and chief scientific officer, Sean Tucker, Ph.D., discussed the data in a presentation today at the 15th Annual World Vaccine Congress in Brussels.

Vaxart COVID-19 Oral Vaccine (VXA-CoV2-1) Clinical Trial

ClinicalTrials.gov Identifier: NCT04563702  -  Safety and Immunogenicity Trial of an Oral SARS-CoV-2 Vaccine (VXA-CoV2-1) Prevention of COVID-19 in Healthy Adults. On February 3, 2021, Vaxart Announced Positive Preliminary Data from Phase 1 Clinical Trial Evaluating Its Oral COVID-19 Tablet Vaccine Candidate.

The Phase 1, open-label, dose-ranging trial is designed to examine the safety and immunogenicity of two doses of VXA-CoV2-1 in up to 48 healthy adult volunteers aged 18 to 54 years old. Enrollment is expected to be completed by early November 2020, with participants receiving the low or high dose of the VXA-CoV2-1 oral tablet on days 1 and 29. Safety, reactogenicity, and immunogenicity assessments will be performed at set times during the active phase. 

Estimated Study Completion Date: October 2021.