By Ryan Lynch

Law360 (November 7, 2023, 7:23 PM EST) — A Federal Circuit judge raised doubts Tuesday about the validity of PureCircle USA Inc.’s patents for non-caloric food sweeteners, suggesting the broad scope of the claims could cover thousands of unknown enzymes and might render the patent claims invalid.

U.S. Circuit Judge Timothy Dyk said PureCircle, which is trying to undo a district court’s order finding two of its patents invalid for lacking written description support, could have easily limited the scope of the claims. Instead, Judge Dyk said the company wrote them so broadly that they cover enzymes that haven’t yet been discovered.

“That’s a fairly broad claim. And that in itself, it seems to me, creates a written description problem,” Judge Dyk said.

Stanley J. Panikowski of DLA Piper, who represents PureCircle, said the future enzymes would have the “same structural features” as those covered by PureCircle’s patents.

PureCircle’s patents for using enzymes to produce chemical compounds called steviol glycosides were challenged by competitor SweeGen Inc. after PureCircle alleged patent infringement in California district court. Both companies manufacture next-generation sweeteners to reduce sugar content in foods and beverages.

Judge Dyk questioned both Panikowski and SweeGen’s attorney, John Christopher Rozendaal of Sterne Kessler Goldstein & Fox PLLC, extensively during an hourlong hearing about the commonality across the enzymes.

“There’s no evidence of what that structure is,” Rozendaal told the court. He said PureCircle’s patents are directed toward not “just one enzyme,” but rather “a whole family of enzymes.”

Judge Dyk seemed sympathetic to this view, noting that the court would need to consider not only the common structural features across enzymes, but also how many potential enzymes could be covered by PureCircle’s patent claims. In a quick calculation, Dyk estimated that PureCircle’s patents could cover roughly 7,000 possible enzymes.

Rozendaal also told the court that the patents should be invalidated because they are directed toward a natural phenomenon. There “isn’t any doubt” that PureCircle’s patented method merely replicates a process that occurs naturally, he said.

Judge Dyk and Panikowski sparred on the twin issues of written claims and whether PureCircle’s patents covered a naturally occurring process. According to Panikowski, the patented method of production could be achieved only by “going to the lab.”

Judge Dyk replied that there was nothing in the patent claims that “tells you how to do that.” In response, Panikowski said it is not required that patent claims provide detailed information about “every step” in the production process.

The patents-in-suit are U.S. Patent Nos. 10,485,257 and 9,243,273.

U.S. Circuit Judges Timothy B. Dyk, Alvin A. Schall and Leonard P. Stark heard the case for the Federal Circuit.

PureCircle is represented by Stanley J. Panikowski and Richard T. Mulloy of DLA Piper, and Stuart E. Pollack of Kilpatrick Townsend & Stockton LLP.

SweeGen is represented by John Christopher Rozendaal, Dennies Varughese, Deirdre M. Wells, Michael E. Joffre, Anna G. Phillips and Sasha S. Rao of Sterne Kessler Goldstein & Fox PLLC.

The case is PureCircle USA Inc. v. SweeGen Inc., case number 22-1946, in the U.S. Court of Appeals for the Federal Circuit.

–Editing by Scott Russell.

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