Gritstone Bio has received a contract valued at up to $433m from the US Biomedical Advanced Research and Development Authority (BARDA) for a Phase IIb clinical trial of its self-amplifying mRNA (samRNA) Covid-19 vaccine candidate.

The vaccine candidate comprises spike plus other viral targets to offer protection against the disease. 

This agreement is part of the US Department of Health and Human Services Project NextGen programme, intended to progress various new therapies and vaccines for Covid-19

As part of the new contract, Gritstone bio will launch a randomised, double-blinded Phase IIb clinical trial enrolling a total of 10,000 subjects.

The trial will analyse the safety, immunogenicity and efficacy of the vaccine candidate against a currently approved Covid-19 vaccine. 

Preparations for the study are currently progressing, with BARDA completely financing its execution. 

Dubbed CORAL-BARDA, the Phase IIb study is expected to commence in the first quarter of 2024.

For conducting the study in the US, Gritstone bio will partner with the Covid-19 Prevention Network.

The company published interim data from the Phase I study of the Covid-19 vaccine (CORAL-BOOST) in June 2023.

Gritstone bio co-founder, president and CEO Andrew Allen said: “Not only does this contract supply the necessary resources to advance the development of CORAL, but it also signifies the trust and confidence the US Government has placed in our novel vaccine approach. 

“Across multiple Phase I studies, our samRNA vaccine, which incorporates both Spike and other viral targets (Spike plus), has demonstrated induction of potent immune responses with potential to drive broad and durable clinical protection – this potential will now be tested in a randomised setting.”