In a Phase 1 trial, the vaccine was generally well-tolerated but did not generate neutralizing antibodies among the 20 study participants who received two doses of the drug.
Vaxart shares at last check dropped 47% to $12.43. They've traded on Wednesday as low as $8.80, down 62%.
Vaxart nonetheless remains confident that its tablet will not only be able to treat the coronavirus but also handle the emerging new strains of the virus.
“Our Phase I results highlight the importance of our differentiated vaccine design, as they suggest VXA-CoV2-1 could have broad activity against existing and future coronavirus strains," Chief Executive Andrei Floroiu said in a statement.
"These results are timely, as we are seeing the emergence of new variants less responsive to first-generation vaccines, thus making potential cross-reactivity another important advantage of next-generation vaccines.”
Vaxart says its vaccine candidate is a "transformative solution" that is "a room-temperature stable oral vaccine that is not only easier to distribute and administer, but may also be more broadly protective.”
The South San Francisco company said it would provide further updates on the study at a symposium at 1:15 p.m. U.S. Eastern on Wednesday.
In November, Vaxart reported promising results from its coronavirus vaccine study, with the drug reducing the viral load in the lungs of hamsters. The stock had more than quadrupled since that report.
Including the current study, a total of 495 patients have been dosed with the drug candidate.