Sanofi announces positive Phase 1/2 study interim results for its first mRNA-based vaccine candidate

Sanofi announces positive Phase 1/2 study interim results for its first mRNA-based vaccine candidate 

• High seroconversion across the three dosages tested and comparable tolerability to other unmodified mRNA COVID-19 vaccines
• Now accelerating transformation of acquired platform to modified mRNA and targeting a modified quadrivalent flu mRNA vaccine in the clinic in 2022

PARIS – September 28, 2021 – Positive interim results from a Phase 1/2 study¹ of Sanofi’s mRNA-based COVID-19 vaccine candidate confirm the potential of recently-acquired Translate Bio’s messenger RNA (mRNA) and lipid nanoparticle (LNP) platform and support Sanofi’s mRNA strategy.

The initial data from Phase 1/2 showed neutralizing antibody seroconversion (defined as 4-fold increase vs baseline) in 91% to 100% of study participants, two weeks after a second injection, across all 3 dosages tested. No safety concern has been observed and the tolerability profile is comparable to that of other unmodified mRNA COVID-19 vaccines. Further data from this first study of Sanofi’s mRNA platform will be presented at a later date.

“We are happy to see those positive initial results. We have made an impressive move just 9 months after the worldwide proof of concept of mRNA vaccines and only 17 since we started this first mRNA vaccine project”, says Jean-Francois Toussaint, Global Head of Research and Development, Sanofi Pasteur. “These results will clearly help inform the path forward for our mRNA development programs. Today, we have a promising mRNA platform, which we’re taking to the next level in development, including moving to modified mRNA, and against other diseases, including flu.”

Targeting 2022 initiation of its clinical studies for an influenza vaccine with modified mRNA, Sanofi launched a Phase 1 clinical trial in June 2021 evaluating an mRNA-based investigational vaccine against seasonal influenza. The trial will evaluate the safety and immunogenicity of a monovalent flu vaccine candidate coding for the hemagglutinin protein of the A/H3N2 strain of the influenza virus across two formulations (MRT5400 and MRT5401) with different lipid nanoparticles.

At the same time, Sanofi continues its efforts in the fight against the COVID-19 pandemic with its adjuvanted recombinant protein candidate vaccine, developed in partnership with GSK. In parallel to its ongoing Phase 3² efficacy and safety study, Sanofi has expanded its development program to include a study of the vaccine as a potentially broadly protective booster to address evolving public health needs. Recently published preclinical data³ indicated the candidate has the potential to strongly boost immune responses following primary vaccination across multiple vaccine technology platforms and against a broad spectrum of variants of concern. The booster studies⁴ began this summer in the U.S., Australia, France, and the UK. First results are expected by the end of Q4 2021.