Sanofi (Euronext: SAN) has filed two patent infringement lawsuits against Pfizer (NYSE: PFE) and Moderna (Nasdaq: MRNA), alleging that Comirnaty and Moderna’s Spikevax and mNEXSPIKE infringe lipid nanoparticle (LNP) patents held by Translate Bio, the mRNA specialist Sanofi acquired for USD 3.2 billion in 2021. Complaints filed in the US District Court for the District of New Jersey (Translate Bio Inc v. Moderna Inc, No. 2:26-cv-08690; Translate Bio Inc v. Pfizer Inc, No. 2:26-cv-08697) allege that the LNP systems used to deliver mRNA payloads in both companies’ COVID-19 vaccines rely on technology covered by Sanofi’s patent estate, as reported by Reuters. A Sanofi spokesperson said the company is “seeking fair compensation for use of its patented technology” rather than an injunction to halt sales, framing this as a royalty-seeking action rather than an attempt to disrupt vaccine supply.
Why it matters
The Sanofi patent case transforms an uncommercialized IP portfolio into an active revenue claim. Sanofi’s own mRNA COVID-19 candidate, MRT5500, was discontinued after Phase I/II, and its mRNA flu program was shelved in 2025, meaning the Translate Bio patent estate has generated no product revenue to date. By asserting these LNP claims against Comirnaty and Spikevax—both fully approved and commercially entrenched—Sanofi is attempting to extract licensing value from a platform it no longer commercializes itself, turning legacy IP into a potential royalty stream tied to Pfizer and Moderna’s tens of billions of dollars in cumulative COVID-19 vaccine sales.
Competitive context
The Sanofi lawsuits extend an already crowded field of mRNA and lipid nanoparticle patent litigation surrounding COVID-19 vaccines. Also this week, Arbutus Biopharma and Genevant Sciences expanded their own LNP patent campaign against Pfizer and BioNTech with new lawsuits in Canada and the Unified Patent Court, building on existing US litigation. GlaxoSmithKline, Bayer, and Alnylam Pharmaceuticals have each previously asserted patents covering different aspects of mRNA or delivery technologies, and Moderna and Pfizer remain locked in their own vaccine patent dispute dating to a 2022 Moderna suit that is still unresolved. Pfizer’s partner BioNTech countersued Moderna in February, arguing that mNEXSPIKE infringes a BioNTech patent—illustrating how the mRNA and LNP patent landscape has become a dense web of overlapping, cross-cutting claims among competitors rather than a single bilateral dispute.