Sanofi’s vaccines global business unit Sanofi Pasteur and Translate Bio have reported preclinical trial results that showed mRNA-based vaccine candidate, MRT5500 induced a favourable immune response against SARS-CoV-2.

These results support progressing the vaccine candidate into clinical development, with a Phase I / II trial expected to commence in the fourth quarter of this year.

Sanofi Pasteur and Translate Bio are developing MRT5500 as part of a partnership deal.

Four dose levels of the vaccine candidate were evaluated at 0.2µg, 1µg, 5µg and 10µg in mice using a two-dose schedule administered three weeks apart.

In non-human primates (NHPs), three dose levels of 15µg, 45µg and 135µg MRT5500 were analysed with a similar two-dose approach.

Data showed that the vaccine candidate induced dose-dependent levels of binding antibodies and neutralising antibodies specific to SARS-CoV-2 spike protein significantly higher than those observed in patients with Covid-19.

Moreover, MRT5500-immunised mice and NHPs demonstrated a Th1-biased T-cell response against SARS-CoV-2.

Translate Bio CEO Ronald Renaud said: “The preclinical results we report in this paper demonstrate the ability of MRT5500 to elicit a favourable immune response in both mice and non-human primates.

“Importantly, these results provide additional support for using our mRNA platform to potentially expedite the development of alternative approaches to traditional vaccines.”

In 2018, the companies signed a collaboration and exclusive license agreement to develop mRNA vaccines for up to five infectious disease pathogens.

Initially, the deal expanded in March to include the development of a novel mRNA vaccine for Covid-19.

Sanofi Pasteur executive vice-president and global head Thomas Triomphe said: “Today’s presentation of these positive results is another development milestone for providing a safe and effective potential vaccine against SARS-CoV2 and shows how promising this technology is.”

In September, Sanofi and GlaxoSmithKline (GSK) initiated a Phase I / II trial to evaluate their adjuvanted recombinant protein-based vaccine candidate against Covid-19.