The European Patent Office has declared an mRNA patent of the US biotech company Moderna invalid in the patent dispute with BioNTech, a German-based company. BioNTech announced on Tuesday to appeal against this decision.

“We are disappointed with the European Patent Office’s decision regarding our ’565 patent,” Moderna said. They remain convinced of the validity of the patent and are considering all options, including appealing the decision to higher courts.” Moderna shares fell more than two percent in premarket trading on Wall Street.

BioNTech welcomed the decision: “We believe that this and other Moderna patents do not meet the requirements for grant and should never have been granted.” The European Patent Office said that the written decision on the matter should be published in the coming weeks or months.

Moderna had sued BioNTech and its US partner Pfizer because it believes that their Covid-19 vaccine violated patents that were registered before the pandemic. The Tübingen rival CureVac has also filed a lawsuit against Biontech because he sees his patents infringed by BioNTech’s successful Covid-19 vaccine. Both BioNTech and Pfizer rejected these allegations and filed a countersuit.