Sanofi joins the mRNA vaccine patent wars

Why it matters: The lawsuits give Sanofi another route to extract value from the mRNA technology it acquired through its $3.2 billion purchase of Translate Bio in 2021, despite failing to bring its own mRNA COVID-19 vaccine to market.

Zoom in: Sanofi filed separate complaints in the U.S. District Court for the District of New Jersey targeting Pfizer and BioNTech’s Comirnaty, as well as Moderna’s Spikevax, next-generation COVID-19 vaccine mNexspike and RSV vaccine mResvia.

• Sanofi alleges that Moderna’s vaccines infringe 10 patents covering mRNA delivery technology, while Pfizer’s Comirnaty infringes eight of those patents. Sanofi is seeking jury trials, damages and other financial compensation. The company’s complaints focus partly on the administration of the vaccines, arguing that healthcare professionals use the patented methods when giving the shots.

How it works: Lipid nanoparticles protect fragile strands of mRNA and help transport them into cells, where the genetic instructions are used to produce a target protein and trigger an immune response. The delivery technology has become one of the most contested parts of the mRNA patent landscape.

The big picture: Pfizer and Moderna have already paid significant sums to settle related disputes.

• Moderna agreed earlier this year to pay Arbutus Biopharma and Genevant Sciences $950 million upfront to resolve litigation over lipid nanoparticle technology.
• Pfizer and BioNTech agreed in 2025 to pay GSK and CureVac $320 million upfront under a separate patent settlement.
• Bayer also sued Pfizer, BioNTech and Moderna in January, alleging that the companies used its technology to improve mRNA stability and protein production.

Yes, but: Sanofi’s claims have not been tested in court, and the filing of a patent lawsuit does not establish that infringement occurred.

The bottom line: Sanofi may have missed the commercial breakthrough of the first mRNA vaccines, but the intellectual property it acquired with Translate Bio could still give it a share of the market’s value. The acquisition also supplied mRNA and lipid nanoparticle capabilities that Sanofi is now combining with other acquired technologies to develop an in vivo CAR-T platform.