A federal judge in Delaware rejected a request on Monday from Pfizer (PFE.US), BioNTech (BNTX.US), and Moderna (MRNA.US) to dismiss a lawsuit brought against them by Monsanto, a unit of German pharmaceutical giant Bayer A.G. (BAYRY.US), over their use of a patent related to mRNA technology.

The patent at issue is U.S. Patent No. 7,741,118, which covers enhancing mRNA in crops to boost the expression of an insect-resistant protein. Monsanto alleges in the suit that the companies used the patent in their COVID-19 mRNA vaccines "to eliminate 'problem' coding sequences in the cellular building blocks, thereby improving mRNA stability and the quantity or quality of the protein produced."

Monsanto filed the lawsuit against the three pharmaceutical companies in January, along with Johnson & Johnson (JNJ.US), which is accused of infringing the patent through a DNA-based process used in vaccine production.

Monsanto, once known for agricultural technology, applied for patent protection on the related technology as early as 1989 and received formal approval in 2010. In 2016, Bayer acquired Monsanto for $66 billion, and this agricultural patent, seemingly unrelated to pharmaceuticals, has now become a powerful tool for asserting rights.

Monsanto originally developed the technology to help crops better express insect-resistant proteins, reduce pesticide use, and increase yields. It never expected that years later it would prove highly useful in the COVID-19 vaccine field. During vaccine development, scientists faced a major challenge: poor mRNA stability led to suboptimal protein expression, directly affecting vaccine immune efficacy. Monsanto's technology happened to solve this pain point by optimizing coding sequences in cellular building blocks to make mRNA more stable, thereby improving protein yield and quality.

Bayer noted in the lawsuit that Pfizer/BioNTech had already acknowledged using codon optimization technology in mRNA products, while Johnson & Johnson's vaccine, although a traditional viral vector type, also requires this technology to enhance mRNA stability and ensure protein expression. Notably, Pfizer/BioNTech's vaccine Comirnaty has generated over $93 billion in sales, drawing even more attention to Bayer's claims.

Moderna had argued that the patent involves an unpatentable "law of nature." However, Judge William Bryson said the companies failed to prove that the '118 patent is invalid or that their vaccines do not infringe it.