After mRNA Rollback, BARDA Pulls Plug on Vaxart Oral COVID Vaccine Trial

Vaxart, a South San Francisco, Calif.-based clinical-stage biotechnology company that specializes in the development of oral solid-dose recombinant vaccines, received notification on Aug. 5, 2025 that Advanced Technology International, a nonprofit manager of R&D collaborations, was placing a stop work order on a Phase IIb trial of Vaxart’s oral pill vaccine candidate against COVID-19 (1–3).

Timing aligns with HHS wind-down

In a form submission signed by Vaxart CEO Steven Lo, the company reported the stop work order to the United States Securities and Exchange Commission (SEC), affirming that it had so far enrolled approximately half of the targeted number of 10,000 participants for the comparative study, for which a contract was reached with the Biomedical Advanced Research and Development Authority (BARDA) of the US Department of Health and Human Services (HHS) in June 2024 (3).

“[Vaxart] has, to date, not been provided with any further details, including the reason for such stop work order,” the SEC submission said (3). “As of July 14, 2025, the date of its last meeting, the independent Data Safety Monitoring Board for the trial tasked with assessing the safety of the trial had determined that the study could continue to proceed without modification.”

Yet the stop work order was delivered on the same day that HHS announced it would be winding down its activities related to messenger RNA (mRNA)-based vaccine development under BARDA, including the canceling or de-scoping of more than 20 projects worth nearly a combined $500 million (4).

Vaxart not listed in HHS release

Vaxart was not named among the companies with whom HHS is terminating contracts, or rejecting or canceling proposals, but an HHS spokesperson responded to a Fierce Biotech request for the reasoning behind the order by sending a link to the Aug. 5 press release from HHS (4,5). According to the Fierce Biotech article, Vaxart is not developing an mRNA vaccine, though does use one as the control in a Phase IIb trial (5).

While the SEC filing did say that Vaxart was being allowed to “continue efforts associated with the per protocol follow-up” for those in the study who are already dosed, the stop work order is the latest change of direction in what has become a boomerang of a drug candidate for the company. A previous stop work order in February 2025 led Vaxart to lay off 10% of its workforce, only for that order to be lifted in late April (6,7).

Fierce Biotech reported that the total estimated ceiling for the funding from BARDA for the Phase IIb trial was approximately $460.7 million (5).

Pharmaceutical Technology® Group has reached out to Vaxart for comment on this latest development but did not receive a response at time of publication. This article will be updated with further information pending receipt of a response.

References

1. Vaxart. About Vaxart. Vaxart.com, accessed Aug. 12, 2025.
2. Advanced Technology International. Advanced Technology International (ATI). ATI.org, accessed Aug. 12, 2025).
3. SEC. Vaxart Inc. 8-K. SEC.gov, Aug. 5, 2025 (accessed Aug. 12, 2025).
4. HHS. HHS Winds Down mRNA Vaccine Development Under BARDA. Press Release. Aug. 5, 2025.
5. Taylor, N. P. Vaxart Seeks Answers as BARDA Funding for Stop-Start Vaccine Project Dries Up Again. FierceBiotech.com, Aug. 12, 2025.
6. Vaxart. Vaxart Provides Business Update and Reports Full Year 2024 Financial Results. Press Release. March 20, 2025.
7. SEC. Vaxart Inc. 8-K. SEC.gov, April 24, 2025 (accessed Aug. 12, 2025).