Sanofi and Translate Bio mRNA COVID-19 vaccine candidate induced high antibody levels in preclinical studies - Seite 2

Key preclinical findings
The main findings of the preclinical studies demonstrate the potential of MRT5500 to elicit neutralizing antibodies against SARS-CoV-2.

In mice, four dose levels were assessed at 0.2, 1, 5 and 10 µg per dose using a two-dose vaccination schedule, administered three weeks apart. MRT5500 induced dose-dependent levels of binding antibodies and neutralizing antibodies specific to the SARS-CoV-2 spike protein. 100% seroconversion was observed at all dose levels after one administration, and a further increase in titers was observed following a second administration. Neutralizing antibody titers were observed across all dose levels after receiving the two-dose-administration regimen. In the higher dose groups (5 µg, 10 µg), titers were detected after one administration of MRT5500 and were more pronounced after the second administration.

In non-human primates (NHPs), three dose levels were assessed at 15, 45 and 135 µg per dose using a two-administration vaccination schedule, three weeks apart. The potency of MRT5500 was assessed by two types of neutralization assays: pseudovirus neutralization and micro-neutralization. After the first administration, the majority of NHPs developed neutralizing antibodies reactive to the SARS-CoV-2 spike protein and those antibody titers were further enhanced after a second administration with 100% of NHPs reaching levels significantly higher than those from human convalescent sera by day 35.

It was also demonstrated that MRT5500-immunized mice and non-human primates exhibited a Th1-biased T cell response against SARS-CoV-2.

The preprint publication “Immunogenicity of novel mRNA COVID-19 vaccine MRT5500 in mice and non-human primates,” is available here.

Shots on goal in the fight against COVID-19
In addition to the mRNA vaccine candidate in collaboration with Translate Bio, Sanofi is collaborating with GSK on a COVID-19 vaccine candidate using the same recombinant protein-based manufacturing technology as one of Sanofi’s seasonal influenza vaccines, combined with GSK’s established pandemic adjuvant platform. The Companies announced the start of the Phase 1/2 clinical trial for their adjuvanted recombinant COVID-19 vaccine candidate in September and anticipate first results in early December 2020, to support the initiation of a pivotal Phase 3 study before the end of the year.