As Pfizer and Moderna have tied off certain threads in their separate webs of mRNA patent litigation, Sanofi has opened a new front to challenge the companies’ blockbuster COVID-19 vaccines.
In separate complaints filed in the U.S. District Court for the District of New Jersey this week, attorneys for Sanofi took aim at the lipid nanoparticle (LNP) tech undergirding the delivery of mRNA in Pfizer’s COVID-19 shot Comirnaty, plus two versions of Moderna’s mRNA coronavirus prophylactic—Spikevax and mNexpsike—and its respiratory syncytial virus (RSV) vaccine mResvia.
LNPs have been a frequent point of contention in the mire of patent litigation that has sprung up around mRNA vaccine technology following the approvals of Pfizer’s and Moderna’s products.
Sanofi’s legal team specifically argues that Pfizer’s and Moderna’s LNP technologies have infringed related patents developed by Translate Bio. Sanofi shelled out $3.2 billion to acquire Translate Bio back in 2021, signaling continued commitment to the field despite the company’s failure to muster its vaccine expertise behind an approved mRNA COVID-19 shot.
Sanofi separately partnered with Novavax in May 2024 to help co-commercialize the Maryland biotech’s approved, protein-based COVID vaccine Nuvaxovid, and to develop potential combination vaccines.
In the complaints, Sanofi’s legal team contends that when healthcare professionals administer Pfizer’s or Moderna’s vaccines, they are ultimately violating a quartet of Sanofi- and Translate-held patents tied to the method for delivery of mRNA, with the drugmakers ultimately shouldering the blame as the vaccines’ developers.
Sanofi is now calling for a jury trial in both cases and, alongside determinations to back up its infringement allegations, the French pharma is hoping to receive damages or other monetary relief from its vaccine rivals.
“Moderna is aware of the litigation and will defend ourselves against these claims,” a spokesperson for the company told Fierce in an emailed statement Wednesday, adding that the company would not comment further.
Pfizer did not immediately respond to Fierce Pharma’s request for comment on the Sanofi court filing.
Multiple biotechs and large pharmas have been waging battle over mRNA patents, with Pfizer and Moderna often at the center, in recent years.
Earlier this year, Moderna resolved some of those disputes, putting patent battles to bed with Alnylam, plus Roivant unit Genevant and infectious disease biotech Arbutus, in that latter case agreeing to pay $950 million upfront while escaping potential future royalties to the plaintiffs on vaccine sales.
Pfizer, for its part, agreed to pay GSK $320 million upfront to settle a similar dispute with the British pharma and its partner CureVac last August.
Still, as the latest legal salvo from Sanofi shows, spats over mRNA IP continue to flare up in 2026.
Notably, Bayer in January filed lawsuits in Delaware against Moderna and Pfizer and its mRNA partner BioNTech, and it separately sued Johnson & Johnson over its non-mRNA COVID shot in New Jersey.
In that instance, Bayer’s legal team argued that Pfizer and Moderna used its tech in creating their vaccines “to eliminate ‘problem’ coding sequences in the building blocks of cells to improve mRNA stability and the amount or quality of protein produced.”
That said, most of the legal disputes over the shots have come back to similar LNP delivery concerns driving the latest action by Sanofi.