Novavax has reported that its protein-based Covid-19 vaccine, NVX-CoV2373, will be included in two clinical trials to analyse it as a booster.

Created from the initial strain of the SARS-CoV-2 virus’ genetic sequence, the vaccine has a purified protein antigen.

Furthermore, it is formulated with a saponin-based Matrix-M adjuvant of the company to boost immune response and induce increased neutralising antibody levels.

The ongoing studies have initiated subject enrolment and will analyse the safety, immunogenicity and reactogenicity of the vaccine.

They are intended to expand knowledge of how various vaccines, including Novavax’s NVX-CoV2373, can be used for boosting after an initial vaccine regimen.

A National Institute of Allergy and Infectious Diseases (NIAID)-sponsored Phase I/II trial is underway to evaluate homologous and heterologous boosting regimens in subjects who have previously received a primary vaccine regimen.

The vaccines used in the initial vaccine series have obtained approval or emergency use authorization (EUA) from the US Food and Drug Administration (FDA).

In this trial, subjects will receive a third dose of either NVX-CoV2373 or any of the three FDA-authorised or -approved Covid-19 vaccines after more than 12 weeks.

Carried out at around ten study centres, the trial will have approximately 1,130 healthy subjects aged 18 years or above, with nearly 180 of them receiving the Novavax vaccine as a heterologous booster.

Assessing the safety, reactogenicity and immunogenicity of delayed heterologous or homologous vaccine doses following EUA vaccines are the primary objectives of the trial.

Subjects will be followed up for a year and topline data and full findings from the trial are anticipated later this year and next year, respectively.

The second study of Novavax’s vaccine, being carried out in the United Arab Emirates (UAE), is an observer-blinded Phase III trial.

It will analyse homologous versus heterologous boosting of subjects previously vaccinated with Sinopharm’s Covid-19 vaccine.

In this study, safety and immunogenicity following boosting with a single dose of Novavax’s vaccine in previously inoculated adults will be studied. 

It will enrol nearly 1,000 subjects of age 18 years or above at two sites in Abu Dhabi, UAE, who will be followed up for six months.

Full data from this trial is expected in the fourth quarter of this year. 

Novavax chief medical officer Filip Dubovsky said: “Our Covid-19 vaccine has already been recommended by multiple national policy bodies for both primary vaccination and booster settings in individuals 18 years of age and older.

“We look forward to adding to this body of evidence to support the expanded use of our protein-based vaccine.”

In February, the company reported that NVX-CoV2373 met the primary immunogenicity endpoint in the paediatric expansion of its Phase III PREVENT-19 trial.