Dow AgroSciences did not infringe on a patent owned by Bayer CropScience for genetically engineering crops to resist the 2,4-D herbicide, a federal appeals court ruled.
The inventors of Bayer’s patent were the first to isolate a gene from bacteria that can neutralize the toxicity of 2,4-D, the ruling said.
The scientists found the genetic sequence responsible for this ability by inserting strands of DNA from 2,4-D-resistant bacteria into bacteria that did not have the trait.
When some previously non-resistant bacteria were then able to withstand the herbicide, the scientists knew they had isolated the right DNA strand.
However, they still did not understand how the enzyme that deactivated 2,4-D actually works, according to the U.S. Court of Appeals for the Federal Circuit.
When Bayer wrote its patent claim, the company “got ahead of the science” by describing the enzyme’s function in a way that was later proved inaccurate, the court said.
The problem lay in Bayer’s understanding of what happened to an oxygen atom in the process of neutralizing 2,4-D, the ruling said.
Bayer described the enzyme using a term — monooxygenase — that inaccurately refers to oxygen’s role in the process, the ruling said.
The enzyme uses two oxygen atoms to “cleave” apart 2,4-D and thus neutralize the chemical.
The term “monooxygenase” indicates that the oxygen atom ends up incorporated into water after the chemical reaction, when it does not.
By the time that Bayer sued Dow over a similarly-acting enzyme in 2010, the company knew about the inaccuracy but had not altered its patent claim, the court said.
Even so, Bayer argued that its claim should be understood more broadly to encompass the cleaving function of the enzyme, regardless of what happened to the oxygen atom.
The federal appeals court has rejected this argument.
“More is needed for a term with an established scientific meaning to be redefined in the specification,” the ruling said.
Even if the enzyme’s function were to be interpreted more broadly, that would make the patent claim so general as to likely render it invalid, the court held.