Sanofi said it is pivoting its messenger RNA vaccine (mRNA) program—acquired over the summer when it bought Translate Bio for $3.2 billion—away from COVID-19 and toward influenza and other pathogens, despite announcing positive Phase I/II data for the vaccine candidate it had been co-developing with Translate.

Thomas Triomphe, executive vice president, Sanofi Pasteur, told reporters Tuesday that Sanofi was vacating the crowded COVID-19 vaccine field after concluding that its mRNA vaccine program stood a better chance of commercial success by refocusing its now clinically validated platform technology to the flu and other diseases.

Sanofi reasons that the mRNA COVID-19 vaccine candidate it is co-developing with Translate Bio, MRT5500, won’t be able to reach the market for at least another year or two—leaving the pharma giant commercially further behind such category leaders as Pfizer and BioNTech’s Comirnaty® and Moderna’s COVID-19 vaccine, also known as mRNA-1273 and marketed in Europe and Canada as Spikevax™.

“If we had come to market at the end of 2022 or early 2023, we would have been late and with no differentiation,” Triomphe said during a media briefing. “There is no public health need now for another messenger RNA vaccine against COVID-19 when you can walk down the street to any pharmacy and get one.”

Triomphe spoke hours after Sanofi trumpeted positive initial data from a Phase I/II trial of MRT5500 that showed neutralizing antibody seroconversion (defined as four-fold increase vs baseline) in 91% to 100% of study participants, two weeks after a second injection, across all three dosages tested. Sanofi said no safety concern had been seen, while the tolerability profile was comparable to that of other unmodified mRNA COVID-19 vaccines.

Further data from the Phase I/II trial, Sanofi added, will be presented at an unspecified later date.

“Promising mRNA platform”

“These results will clearly help inform the path forward for our mRNA development programs,” Jean-Francois Toussaint, global head of research and development, Sanofi Pasteur, said in a statement. “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.”

MRT5500 is an mRNA vaccine based on Translate Bio’s MRT™ platform, which it acquired from Shire in 2017. Sanofi liked the unmodified mRNA platform so much that it bought Lexington, MA-based Translate for $3.2 billion over the summer, in a deal completed September 14.

Sanofi and Translate Bio began partnering on mRNA vaccines in 2018, launching an up-to-$805 million-plus collaboration in June 2018. Last year, Sanofi and Translate Bio expanded their collaboration to develop mRNA vaccines for infectious diseases, with the pharma giant nearly tripling to more than $2.3 billion its potential payout to Translate, and the companies increasing from five to seven the maximum number they plan to develop under that partnership.

Most of that expanded collaboration (up to $1.94 billion) consisted of payments tied to milestones, with Sanofi committing $425 million to Translate Bio upfront, consisting of $300 million cash and a private placement common stock investment of $125 million.

“We generated immunogenicity data, neutralization data for a number of infectious disease targets, both from the viral and the bacterial side. The productivity of that relationship was just a very natural foundation for when we decided to start working together on COVID-19,” Translate Bio CEO Ronald C. Renaud Jr. said in September 2020 as a guest on “GEN Live”, GEN’s monthly live-streaming video discussion series.

Sanofi is not abandoning COVID-19 vaccine and drug development entirely. The company said it will continue development of the adjuvanted recombinant protein vaccine candidate developed with GlaxoSmithKline (GSK), which combines Sanofi’s S-protein COVID-19 antigen based on recombinant DNA technology and GSK’s pandemic AS03 adjuvant. The Sanofi-GSK vaccine candidate advanced in May into a Phase III trial in 35,000 volunteers aged 18 and older from the United States and countries in Asia, Africa, and Latin America.

The greater public health need, Sanofi concluded, is an mRNA flu vaccine, where Sanofi has targeted next year to begin clinical studies of a modified quadrivalent seasonal influenza candidate.

Two formulations

Sanofi is already assessing two mRNA vaccine formulations with different lipid nanoparticles based on Translate Bio tech—MRT5400 and MRT5401—against seasonal influenza in an ongoing Phase I trial that launched in June. That trial is evaluating 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 both vaccine formulations.

Last month, Translate Bio said in a regulatory filing that it and Sanofi expected to have interim data from the trial by the end of this year.

Translate Bio also disclosed in the filing that Sanofi paid it a milestone payment of $25 million upon the start of the Phase I/II trial of MRT5500 in March, followed three months later with another $50 million from Sanofi upon the successful manufacture, release and delivery of clinical drug product to supply the Phase I trial of MRT5400 and MRT5401. Also in June, Sanofi paid Translate Bio a $4 million milestone payment upon the start of the MRT5400-MRT5401 trial.

Sanofi’s pivot to flu and pathogens marks the company’s latest move toward positioning itself as a leader in mRNA vaccine development.

In April, Sanofi acquired Tidal Therapeutics for $160 million upfront plus up to $310 million tied to achieving milestones. Privately-owned Tidal had developed an mRNA-based tech platform for in vivo reprogramming of immune cells inside the body, allowing for an off-the-shelf approach to developing CAR-T therapies.

Tidal’s platform uses proprietary nanoparticles to deliver mRNA selectively, with initial applications targeting specific types of immune cells. Sanofi concluded that the platform offered potential to expand its research capabilities in both immuno-oncology and inflammatory diseases, as well as applicability to other disease areas as well.

Two months after buying Tidal Therapeutics, Sanofi announced plans in June to launch an mRNA Center of Excellence with approximately €400 million ($467 million) a year in funding. That Center is intended to accelerate the development and delivery of next-generation vaccines by joining approximately 400 employees together with end-to-end mRNA vaccine capabilities that include dedicated R&D, digital, and chemistry, manufacturing and controls (CMC) teams across sites at Cambridge, MA, and Marcy l’Etoile, Lyon, France.

Sanofi’s share price on the Euronext Paris market dipped 0.35% or €0.29 ($0.34) in late-day trading, to €81.82 ($95.59).