Moderna and Pfizer, the developers of COVID-19 shots Spikevax and Comirnaty, are each facing a lawsuit from biotech firm Promosome, accusing them of infringing on a patent covering its messenger RNA (mRNA) technology.

The lawsuits represent the latest legal matter embroiling the two shots. Last summer, Moderna sued Pfizer and BioNTech in Massachusetts, alleging they copied its patented mRNA technology for Comirnaty.

In separate suits filed in federal court in San Diego on Tuesday, Promosome argued that vaccine makers Moderna and Pfizer/BioNTech cloned its method for overcoming a key challenge faced by mRNA vaccines. 

That challenge involves boosting the amount of protein expressed per unit of mRNA – in this case, the coronavirus spike protein – such that an acceptably small dose of the shot can be used safely and effectively.

Promosome is bringing the suits in order to receive what it refers to in the complaints as a “rightful share” of the tens of billions in Spikevax and Comirnaty revenues. 

“Unfortunately, these big pharma companies have failed to give Promosome what it deserves,” lead lawyer Bill Carmody, of the firm Susman Godfrey, stated in a press release.

Promosome, based in San Diego and New York, was launched to bring to market technology developed by the Scripps Research Institute in La Jolla, California.

The mRNA is genetic material that instructs the body how to produce proteins, so that its natural immune system will then recognize the newly minted spike protein as foreign and attack it. Promosome says its scientists discovered a method for increasing protein expression via a small amount of mRNA.

The biotech allegedly taught its novel method to Moderna leaders, including CEO Stéphane Bancel and president Stephen Hoge, under a 2013 confidentiality agreement. Spikevax’s mRNA sequence, which has since been made public, “starkly reveals” that Moderna copied the method in the patent, according to the first suit. 

The second suit asserts that, in 2015, Promosome shared its technology with then BioNTech scientist Katalin Karikó, whose company went on to incorporate the method for Comirnaty. Neither company licensed the technology for its vaccine, however.

Pfizer and Moderna, both contacted for comment, did not respond at press time. 

Pfizer’s global Comirnaty revenues in 2022 totaled about $37.8 billion, $8.8 billion of it from the U.S. Last year Moderna’s Spikevax sales were $4.4 billion in the U.S. and $18.4 worldwide.