Three top names in the fight against the coronavirus and the COVID-19 disease that can result from it have been sued for patent infringement. The trio includes Regeneron Pharmaceuticals (REGN -0.09%), Pfizer (PFE -0.19%), and BioNTech (BNTX -0.45%). The plaintiff is privately held Allele Biotechnology and Pharmaceuticals.

Allele alleges that the three all used its mNeonGreen fluorescent protein to develop their COVID-19 products without paying royalties for the substance. Medical researchers inject fluorescent proteins into cells to track reactions within those bodies. This tracking is used to help determine the effect of medicines and vaccines on the body.

A researcher studying a sample in a petri dish.

Image source: Getty Images.

Regeneron is currently developing REGN-COV2, an experimental cocktail of two antibodies to treat COVID-19. The company became a hot topic last week when it was revealed President Donald Trump was administered REGN-COV2 as part of his treatment for COVID-19.

Pfizer and BioNTech have teamed up to develop a coronavirus vaccine; their candidate, BNT162b2, is considered one of the front-runners in the race to bring a vaccine to market.

mNeonGreen was allegedly used in both programs. Allele said in its complaint, filed in a California federal court, that "only through the use of mNeonGreen" were the companies able to develop their products with relative speed.

This, in turn, allowed them to be awarded "an immediate $400 million in grants and over $4 billion in sales of the vaccine to date," although BNT162b2 has, like other candidates, not yet been approved for use by any major pharmaceutical regulator. Allele is seeking to recover the royalties for its product, although it wasn't immediately clear how much it is requesting.

Regeneron said it disagreed with Allele's complaint and would "vigorously defend" its position in court. Neither Pfizer nor BioNTech has formally reacted to the lawsuit.