The European Patent Office (EPO) has declared an mRNA patent held by US biotech company BioNTech invalid in a patent dispute with Moderna, the other major coronavirus vaccine manufacturer. In response to the decision, Moderna announced on Tuesday that it will appeal the ruling.

Moderna disagrees with the EPO’s decision regarding the ‘565 patent and believes it remains valid. Shares of Moderna fell more than 2% in premarket trading on Wall Street after the news was announced.

BioNTech welcomed the decision, stating that it believes that Moderna patents do not meet the requirements for grant and should never have been granted. The EPO said that a written decision on the matter would be published in the coming weeks or months.

Moderna had filed a lawsuit against BioNTech and its US partner Pfizer earlier this year, alleging that their Covid-19 vaccine violated patents registered before the pandemic. CureVac, another Tübingen rival, also filed a lawsuit against BioNTech over similar claims. BioNTech and Pfizer denied any wrongdoing and filed a countersuit against Moderna and CureVac.