UPDATE 3-GlaxoSmithKline sues Pfizer and BioNTech over Covid-19 vaccine technology

(Adds response from BioNTech in paragraph 3)

By Blake Brittain

April 25 (Reuters) - GlaxoSmithKline sued Pfizer and BioNTech in Delaware federal court on Thursday, accusing them of infringing GSK patents related to messenger RNA (mRNA) technology in the companies' blockbuster COVID-19 vaccines.

GSK said in the lawsuit that Pfizer and BioNTech's Comirnaty vaccines violate the company's patent rights in mRNA-vaccine innovations developed "more than a decade before" the outbreak of the COVID-19 pandemic.

A Pfizer spokesperson said in a statement that the company is "confident in our IP position around Comirnaty" and intends to "vigorously defend" against GSK's claims. A BioNTech spokesperson declined to comment on the complaint.

A GSK spokesperson said the company believes its patents "provided the foundational technology used in Pfizer and BioNTech’s COVID-19 mRNA vaccines," and that it is "willing to license these patents on commercially reasonable terms and to ensure continued patient access" to the shots.

The lawsuit adds to a web of high-stakes U.S. court cases involving Pfizer, BioNTech and Moderna over patent royalties for technology used in their vaccines, including a case brought by Moderna against Pfizer in 2022.

Pfizer made $11.2 billion from sales of Comirnaty last year, while Moderna earned $6.7 billion in revenue from its vaccine Spikevax. Sales of both vaccines declined significantly last year from 2022.

London-based GSK asked the court for an unspecified amount of monetary damages from Pfizer and BioNTech that includes an ongoing patent-licensing fee.

GSK said in the complaint that its patents cover technology for transporting fragile mRNA into human cells that scientists began developing in 2008. GSK said it bought the rights to the inventions when it acquired part of Novartis' vaccines business in 2015.

GSK also sued Pfizer for patent infringement last year over technology used in Pfizer's respiratory syncytial virus (RSV) vaccine Abrysvo. Pfizer has denied GSK's claims in that case. (Reporting by Blake Brittain Editing by David Bario and Chizu Nomiyama and Franklin Paul)