PureCircle USA Inc. v. SweeGen, Inc. (Fed. Cir. 2024)

May 22, 2024
Presented By
  • Whitney Remily

In PureCircle USA Inc. v. SweeGen, Inc. (Fed. Cir. 2024), the Fed. Cir. affirmed the District Court’s invalidation of the claims asserted against Defendant SweeGen as being directed to patent-ineligible subject matter under 35 U.S.C. § 101 and failure to satisfy the written description requirement of 35 U.S.C. § 112(a). PureCircle owns U.S. Patent Nos. 9,243,273 (“’273 patent”) and 10,485,257 (“’257 patent”), directed to production of sugar substitutes, which are found in stevia plants. Because plants have only trace amounts of Reb X, it is not commercially viable to extract from the plants. PureCircle patented a method for producing Reb X using UDP-glucosyltransferases (“UGTs”), the same enzymes used in plants to synthesize the compound.  The claims functionally claimed a genus of enzymes capable of transferring a glucose unit from a uridine diphosphate glucose molecule to a steviol glycoside molecule. The court held any structural features common to the members of the genus were not sufficiently disclosed so as to allow one of skill in the art to visualize or recognize the members of the genus. Further, claims directed specifically to enzyme UGT76G1 were held to be patent-ineligible because the enzyme is naturally found in stevia plants, and naturally converts Reb D to Reb X. Although the claims recited a specific percentage conversion, this was not sufficient because the claim did not provide sufficient steps or guidance regarding how to achieve the result.


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