Pfizer Inc. (PFE  ) and Moderna Inc. (MRNA  ) are set for more legal battles over their rival COVID-19 vaccines after London's High Court delivered a mixed ruling on two of Moderna's patents.

This decision is likely to trigger a series of appeals in the ongoing London litigation.

Pfizer and its German partner BioNTech SE (BNTX  ) initiated the lawsuit against Moderna in London in September 2022, seeking to revoke two of Moderna's patents.

In response, Moderna accused Pfizer and BioNTech of infringing on its patents. These lawsuits are part of a global legal struggle over messenger RNA (mRNA) technology.

Moderna is seeking damages for what it alleges to be the unauthorized use of its patents by Pfizer and BioNTech's Comirnaty vaccine.

Last year, Pfizer generated $11.2 billion in sales from Comirnaty, while Moderna earned $6.7 billion from its Spikevax vaccine, highlighting the substantial financial stakes.

Pfizer and BioNTech argued that Moderna's mRNA technology developments were obvious enhancements of prior work and sought to invalidate Moderna's patents.

The High Court's ruling declared one of Moderna's mRNA technology patents invalid but upheld another, confirming that Pfizer and BioNTech's Comirnaty vaccine had infringed on it.

All three companies expressed disagreement with the parts of the decision that went against them and are expected to seek permission to appeal.

Citing a Moderna spokesperson, Reuters highlighted that the court recognized the innovation of its scientists by confirming the validity and infringement of one of its patents.

Meanwhile, Pfizer, BioNTech, and Moderna are also engaged in parallel legal proceedings in Germany, the Netherlands, Belgium, the United States, and the European Patent Office, many of which are currently on hold.

The London ruling arrives at a challenging time for Moderna, whose shares have dropped over 70% since the pandemic's peak due to declining demand and sales for Spikevax.

Pfizer's shares have also declined about 29% since mid-2021.

Price Action: MRNA shares are down 0.01% at $115.94 at the last check on Tuesday.