Moderna sued Pfizer and its German partner BioNTech on Friday for patent infringement in the development of the first Covid-19 vaccine approved in the United States, alleging they copied technology that Moderna developed years before the pandemic.

Pfizer shares fell nearly 1 per cent, while BioNTech US-listed shares were down about 1.5pc and Moderna shares slipped 1.7pc on Friday.

The lawsuit, which seeks undetermined monetary damages, was filed in US District Court in Massachusetts. In a news release on Friday, Moderna said the lawsuit would be filed also in the Regional Court of Duesseldorf in Germany.

Contacted by Reuters, a spokesperson for the Duesseldorf court said: “I cannot currently confirm the receipt of such a claim.”

“We are filing these lawsuits to protect the innovative mRNA technology platform that we pioneered, invested billions of dollars in creating, and patented during the decade preceding the Covid-19 pandemic,” Moderna Chief Executive Stephane Bancel said in the news release.

Moderna said its lawsuit was not meant to stop people from getting vaccines.

Moderna Inc, on its own, and the partnership of Pfizer Inc and BioNTech were two of the first groups to develop a vaccine for the novel coronavirus.

In an emailed statement, a Pfizer spokesperson said: “Pfizer/BioNTech has not yet fully reviewed the complaint but we are surprised by the litigation given the Covid-19 vaccine was based on BioNTech’s proprietary mRNA technology and developed by both BioNTech and Pfizer.”

“We remain confident in our intellectual property supporting the Pfizer/BioNTech vaccine and will vigorously defend against the allegations of the lawsuit,” the spokesperson said.

BioNTech did not immediately reply to separate requests for comment.

Just a decade old, Moderna, based in Cambridge, Massachusetts, had been an innovator in the messenger RNA (mRNA) vaccine technology that enabled the unprecedented speed in developing the Covid-19 vaccine.

An approval process that previously took years was completed in months, thanks largely to the breakthrough in mRNA vaccines, which teach human cells how to make a protein that will trigger an immune response.

Germany-based BioNTech had also been working in this field when it partnered with the U.S. pharma giant Pfizer.

The US Food and Drug Administration granted emergency use authorization for the Covid-19 vaccine first to Pfizer/BioNTech in December 2020, then one week later to Moderna.

Moderna’s Covid vaccine — its lone commercial product — has brought in $10.4 billion in revenue this year while Pfizer’s vaccine brought in about $22 billion.

The lawsuit will likely take years to play out, according to Cowen & Co analyst Tyler Van Buren.

Moderna alleges Pfizer/BioNTech, without permission, copied mRNA technology that Moderna had patented between 2010 and 2016, well before Covid-19 emerged in 2019 and exploded into global consciousness in early 2020.

Early in the pandemic, Moderna said it would not enforce its Covid-19 patents to help others develop their own vaccines, particularly for low- and middle-income countries. But in March 2022 Moderna said it expected companies such as Pfizer and BioNTech to respect its intellectual property rights. It said it would not seek damages for any activity before March 8, 2022.

Patent litigation is not uncommon in the early stages of new technology.

Pfizer and BioNTech are already facing multiple lawsuits from other companies who say the partnership’s vaccine infringes on their patents. Pfizer/BioNTech have said they will defend their patents vigorously.

Germany’s CureVac, for instance, also filed a lawsuit against BioNTech in Germany in July. BioNTech responded in a statement that its work was original.

Moderna has also been sued for patent infringement in the United States and has an ongoing dispute with the U.S. National Institutes of Health over rights to mRNA technology.

In Friday’s statement, Moderna said Pfizer/BioNTech appropriated two types of intellectual property.

One involved an mRNA structure that Moderna says its scientists began developing in 2010 and were the first to validate in human trials in 2015.

“Pfizer and BioNTech took four different vaccine candidates into clinical testing, which included options that would have steered clear of Moderna’s innovative path. Pfizer and BioNTech, however, ultimately decided to proceed with a vaccine that has the same exact mRNA chemical modification to its vaccine,” Moderna said.

The second alleged infringement involves the coding of a full-length spike protein that Moderna says its scientists developed while creating a vaccine for the coronavirus that causes Middle East Respiratory Syndrome (MERS).

Although the MERS vaccine never went to market, its development helped Moderna rapidly roll out its Covid-19 vaccine.