By Robb M. Stewart


Vaxart Inc.'s shares climbed in early trading Monday after the U.S. Food and Drug Administration cleared its investigational new drug application for a tablet Covid-19 vaccine candidate.

In morning trading, the shares were 11% stronger at $7.95, widening the year-to-date gain to 39%.

The biotechnology company Monday said it will begin a Phase II clinical trial of its S-only oral tablet vaccine candidate in the second half of the year.

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, the company said. The planned 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, it said.

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 10:13 ET (14:13 GMT)

Copyright (c) 2021 Dow Jones & Company, Inc.