Moderna has dosed the first subject in Phase II clinical trial of its Omicron-specific bivalent booster candidate, mRNA-1273.214.

This booster merges the company’s Covid-19 vaccine, mRNA-1273, and an Omicron-specific booster candidate, mRNA-1273.529.

An expansion of a prior study, this Phase II trial will analyse the safety, immunogenicity and reactogenicity of mRNA-1273.214 administered as a single booster in adult subjects aged 18 years and above.

These subjects must have previously received the initial two-dose vaccine regimen and a 50µg booster dose of mRNA-1273 a minimum of three months ago. 

Moderna intends to enrol nearly 375 subjects in the trial that will be carried out at around 20 study centres in the US.

Furthermore, the company is analysing the mRNA-1273.529 vaccine in a Phase II clinical trial in the US and a Phase III UK trial carried out in partnership with UK National Institute for Health Research (NIHR). 

The dosing of the participants with mRNA-1273.214 in the trial is anticipated shortly.

Moderna CEO Stéphane Bancel said: “We are pleased to begin this study of our bivalent booster candidate that includes our Omicron-specific candidate and the Moderna Covid-19 vaccine. 

“Our mRNA platform allows us to pivot with speed and flexibility to create a bespoke vaccine to target new variants as they arise. 

“Our goal has been to remain ahead of the virus and we are committed to generating and sharing data with public health authorities as they prepare for the fall booster season.”

In January this year, the company dosed the first participant in the Phase II trial of mRNA-1273.529 in the US.