GlaxoSmithKline (GSK) and CureVac’s second generation COVID-19 vaccine, CV2CoV, has generated positive preclinical data, the companies announced yesterday.

Preclinical testing in a rat model showed that CV2CoV induces high levels of antigen production and strong, dose-dependent immune responses in vaccinated animals.

The data, published on the pre-print server bioRxiv, also showed that rats immunised with the second-generation jab demonstrated ‘fast onset’ of strong immune responses after their first dose.

On top of that, the serum of vaccinated animals showed significant cross-neutralisation against variants of concern, including those first discovered in Denmark (B.1.1.298), the UK (B.1.1.7) and South Africa (B.1.351).

CV2CoV differs from CureVac’s first-generation vaccine candidate, CVnCoV, having been based on a new mRNA backbone that uses targeted optimisations to improve both intracellular mRNA stability and translation for increased and extended protein expression.

In a statement, GSK and CureVac said that these optimisations could potentially enable stronger immune responses at low doses to support the development of multivalent vaccines that can target COVID-19 variants.

GSK and CureVac first announced the collaboration in February 2021, with the aim of developing second-generation vaccines and evaluating a multivalent or combination approach to address multiple emerging variants in one vaccine.

The first clinical trials for CV2CoV are expected to begin in the third quarter of 2021.

”To successfully fight the COVID-19 pandemic in the long term, we will need different vaccines and we need to be able to respond effectively to emerging variants,” said Roger Connor, president R&D at GSK.

“We are pleased with these pre-clinical results as they show the potential of the next generation mRNA technology we are developing together with CureVac,” he added.