By Robb M. Stewart


Vaxart Inc. will begin a clinical trial of its S-only oral tablet Covid-19 vaccine candidate in the second half of the year after the U.S. Food and Drug Administration cleared its investigational new drug application.

The biotechnology company on Monday said preliminary data from a non-human primate study indicates that the S-only vaccine produced much higher serum antibodies than the one expressing both S and N proteins. A planned Phase 2 trial would allow Vaxart to compare the S-only and S+N vaccine candidates to help decide which approach offers the best way forward in its Covid-19 vaccine-development program, particularly given emerging variant strains.

In premarket trading, Vaxart's shares were 14% higher after ending Friday at $7.19, up 26% since the end of last year.

In February, Vaxart said it had completed a Phase 1 clinical trial for its oral S+N COVID-19 vaccine, the results of which found that the investigational oral vaccine triggered multiple immune responses against SARS-CoV-2 antigens, while reaching primary and secondary endpoints of safety and immunogenicity.

"Our Phase I results from the S+N vaccine candidate showed remarkable T-cell responses and a mucosal antibody response, but not as strong serum antibody responses," said Sean Tucker, Vaxart's chief scientific officer.

The company said the development of the S-only oral tablet and other S-only constructs will proceed in parallel with the S&N construct.


Write to Robb M. Stewart at


(END) Dow Jones Newswires

August 02, 2021 08:37 ET (12:37 GMT)

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