LONDON (Reuters) -Pfizer ( PFE ) and its German partner BioNTech on Friday lost their bid to overturn a ruling that their COVID-19 vaccine infringed one of Moderna's ( MRNA ) patents at London's Court of Appeal.

Last year, the High Court ruled that one of Moderna's ( MRNA ) patents relating to the messenger RNA (mRNA) technology which underpinned its COVID-19 vaccine was valid and that Pfizer ( PFE ) and BioNTech's Comirnaty vaccine had infringed it, meaning Moderna ( MRNA ) is entitled to damages in relation to sales after March 2022.

The High Court also ruled that the other Moderna ( MRNA ) patent under challenge in the case was invalid. Moderna ( MRNA ) was refused permission to appeal against that decision.

But Pfizer ( PFE ) and BioNTech were granted permission to appeal in an attempt to try and invalidate Moderna's ( MRNA ) second patent and appealed earlier this month, arguing Moderna's ( MRNA ) developments of mRNA technology were obvious developments of previous work, rendering the patent invalid.

But Judge Richard Arnold rejected Pfizer ( PFE ) and BioNTech's appeal, in the latest ruling in the legal dispute between Pfizer ( PFE ), BioNTech and Moderna ( MRNA ) over their competing vaccines, which helped save millions of lives during the pandemic.

The companies have also been involved in proceedings in Germany - where a court ruled in Moderna's ( MRNA ) favour in March - the United States Patent Office, which held that two Moderna COVID-19 vaccine patents were invalid, and elsewhere.