After $3.2B deal, Sanofi dumps Translate's mRNA COVID vaccine but hits the gas on switch to modified molecules

The ink on Sanofi’s $3.2 billion takeover of Translate Bio is barely dry, but the French big pharma is already tweaking its plans, dumping a COVID-19 vaccine prospect after seeing interim phase 1/2 data and accelerating its switch to modified mRNA. 

Sanofi framed the interim results as positive but sees no value in bringing a mRNA vaccine to market so long after the front-runners. Between 91% and 100% of participants across the three doses had a fourfold or greater increase in neutralizing antibody levels over baseline two weeks after receiving their second dose. Sanofi said there were no safety concerns, and tolerability was “comparable” to that of other unmodified mRNA vaccines. 

BioNTech, the originator of the vaccine sold by Pfizer, and Moderna both modified their mRNA to try to bypass the inflammatory reaction against foreign nucleic acid. CureVac advanced an unmodified mRNA that relied on changes to the RNA sequence to escape detection by the immune system.

The runaway successes of the BioNTech-Pfizer and Moderna vaccines contrasted sharply with clinical data on the jab from CureVac. While the variants circulating at the time of the CureVac clinical trial may partly explain the divergent efficacy results, the studies also bolstered the case of researchers who see mRNA modification as critical to the success of the modality.

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Sanofi appears to have joined the proponents of modified mRNA. Translate Bio, which Sanofi bought for $3.2 billion to expand in mRNA, was focused on unmodified nucleic acids, reflecting the work of the Shire research group behind its platform. And in July, Thomas Triomphe, head of Sanofi Pasteur, told investors the company would explore both unmodified and modified mRNAs to get the best possible constructs. 

Yet, modified mRNA is now hogging the limelight at Sanofi. In a statement to disclose the phase 1/2 data, Sanofi said it is “accelerating transformation of acquired platform to modified mRNA.” 

The goal is to have a modified quadrivalent flu mRNA vaccine in the clinic next year. Sanofi and Translate Bio became the first companies to start a trial of a seasonal mRNA flu vaccine candidate in June, but their attention is already turning to its modified, quadrivalent successor. This week, Pfizer began a phase 1 clinical trial of a quadrivalent mRNA vaccine against influenza.