Vaxart Announces Agreement with hVIVO to Develop World’s First Human Omicron Challenge Model

Vaxart, Inc. announced an agreement with hVIVO Services Limited, a subsidiary of Open Orphan plc under which hVIVO will conduct a characterization study and, if successful, develop a human challenge model based on the Omicron variant of SARS-CoV-2 with the intent to conduct a subsequent Phase II Human Challenge Trial (HCT) of Vaxart’s oral COVID-19 vaccine pill candidate.

Vaxart is developing an oral COVID-19 vaccine pill and is the first company to progress to a Phase II clinical trial with an oral candidate. Vaxart is now also the first company to announce the intent to test a vaccine candidate through a COVID-19 human challenge study using the now prevalent Omicron variant, rather than the original Wuhan strain.

hVIVO is a specialist contract research organization (CRO) and global leader in testing infectious and respiratory disease products using HCTs.

“We are excited at the prospect of testing our vaccine candidates in a human Omicron challenge model particularly given the preclinical data we reported earlier this month that showed two of our COVID-19 vaccine constructs could protect against the Omicron BA.1 variant. A human challenge study of our oral COVID-19 vaccine pill candidate against the Omicron variant of SARS-CoV-2 is the most rapid and direct way to assess the efficacy of this candidate against a highly prevalent viral strain,” said Dr. James Cummings, Vaxart’s Chief Medical Officer.

“hVIVO has pioneered COVID-19 characterization and the Omicron human challenge model, and the use of this model in our planned Phase II HCT can rapidly generate robust, controlled data on the ability of our COVID-19 vaccine candidate to prevent infection and the development of symptomatic disease, as well as its effect on viral shedding, which plays a critical role in the spread of infection from one person to another. The results of this study will inform the next steps in the development of our COVID-19 vaccine candidate, which we believe has the potential to transform personal and public health approaches to controlling the global pandemic,” added Dr. Cummings.

“We are proud to be developing the world’s first Omicron human challenge model and to welcome Vaxart as the first client of this program,” said Yamin ‘Mo’ Khan, Chief Executive Officer of Open Orphan. “The successful completion of the world’s first COVID-19 characterization, which was published in Nature Medicine earlier this year, has given our customers the confidence to move forward with the less severe yet more infective Omicron challenge model.”

Following manufacture of the challenge virus, hVIVO will conduct a characterization study to establish a dose of the Omicron challenge virus that will cause a safe and reliable infection in healthy volunteers. The study will enroll healthy male and female volunteers who have previously been vaccinated against or infected with SARS-CoV-2, with no known risk factors for severe COVID-19 and low levels of serum neutralizing antibodies (and therefore still likely to become infected following inoculation). Subject to the successful completion of the characterization study and receipt of relevant regulatory approvals, the Omicron human challenge trial is expected to begin in 2023.