A recent Federal Circuit case exemplifies the importance of adequately describing inventions in patent applications. PureCircle, and its related entities sued SweeGen and related companies for infringement of U.S. Patent Nos. 9,243,273 (Pat. ‘273) and 10,485,257 (Pat. ‘257).[i]
The two patents are directed to methods of producing non-caloric sweetener molecules found in stevia in miniscule amounts through an enzymatic process relying on UDP-glucosyltransferases.[ii] The claims were drafted broadly, as seen by claim 1 from Pat. ’273;
1. A method for making Rebaudioside X comprising a step of converting Rebaudioside D to Rebaudioside X using a UDP-glucosyltransferase, wherein the conversion of Rebaudioside D to Rebaudioside X is at least about 50% complete.[iii]
A specific UDP-glucosyltransferase (UGT) was disclosed and claimed, naturally-occurring UGT76G1.[iv] The specification shows the process of conversion of rebsudioside from stevioside;[v]
The claims were challenged for lack of written description and unpatentable subject matter.[vi] The court noted that to claim a genus, i.e. more than one variant, U.S. law “requires the disclosure of either a representative number of species falling within the scope of the genus or structural features common to the members of the genus so that one of skill in the art can ‘visualize or recognize’ the members of the genus.”[vii] PureCircle, and SweeGen stipulated that the UGTs were defined by their function, i.e. transferring glucose units from uridine diphosphate glucose to steviol glycosides, but SweeGen subsequently challenged the definition for lacking a representative number of species or common structure.[viii] PureCircle countered that there are 5 known enzymes that have known ability to steviol synthesis, and homology mutation modeling can identify variations with reasonable certainty.[ix] Further, it was argued that a single enzyme can meet the written description requirement, but the court noted that this is the case only where there exists blaze marks to identify the requirements for inclusion in a genus.[x] In response to arguments that the active site of the disclosed enzyme is sufficient to support a genus of enzymes, the court found no structural features identified in the patent to allow determination of the genus members, that the specification lacked an information on the homology modeling, and even if homology modeling is known by the art, extensive trial and error testing would be required after the modeling to identify potential active candidates.[xi] The court then noted a difference between the specification enabling one in the field on identifying variations, and whether the variants were disclosed to one of ordinary skill in the field, i.e. identifying to him or her what was invented.[xii] The court also noted there is a possibility of unknown enzymes that may function to convert molecules, which would not necessarily share a common structure with the disclosed UGT enzyme, and the specification did not identify the amino acid sequences that are critical to the function of the enzyme.[xiii] Further, homology modeling alone is insufficient to determine any enzyme capable for producing the stevia molecule; only to identify common structures.[xiv]
The court found the “claims merely recite a description of the problem to be solved while claiming all solutions to it and . . . cover any compound later actually invented and determined to fall within the claim’s functional boundaries—leaving it to the pharmaceutical industry to complete an unfinished invention.”[xv] Furthermore, the specific enzyme, UGT76G1 was not shown to be typical of the entire genus of UGTs claimed.[xvi]
The court also noted that UGT76G1, a naturally occurring enzyme, renders any claims dependent upon that enzyme to be unpatentable under § 101.[xvii] PureCircle argued the amount of rebsudioside produced naturally is very small, whereas the claims recite that conversion of rebsudioside D to rebsudioside X of at least 50% and such levels of conversion would not be attained naturally.[xviii] The court countered that the recitation to 50% completion is an abstract idea, and found “[t]o be eligible under § 101, an invention must have the ‘specificity required to transform a claim from one claiming only a result to one claiming a way of achieving it.’” [xix] Here, the court found the claim failed to provide steps or guidance to achieve the 50% conversion rate, other than using the natural enzyme.[xx]
As illustrated from the court in PureCircle v. SweeGen, written description[xxi] is plaguing patent owners, and a strong defensive mechanism for defendants. Disclosing multiple examples of claimed subject matter, identifying critical components for a genus, and determining how the subject matter functions can support written description, as well as broader claims. In pharmaceutical cases, structure activity relationship (SAR) testing, mechanism of action, and a select representation of chemical classes are extremely helpful in showing use of different variations of the invention and support for a broader genus. In biotechnology cases, such as the PureCircle v. SweeGen, identification of the active site and any cofactor or coenzyme sites are important, as well as identification of the interaction between the substrate and enzyme to identify interactions critical to activity.
[i] PureCircle USA Inc. v. SweeGen, Inc., et al., No. 2022-1946, slip opinion at 1 (Fed. Cir., Jan. 2, 2024).
[ii] Id. at 2.
[iii] Id. at 2-3.
[iv] Id. at 3.
[v] Markosyan, et al., (U.S. Pat. 9,243,273), Fig. 3.
[vi] PureCircle USA Inc. No. 2022-1946 at 3.
[vii] Id. at 4 (citing Ariad Pharms., Inc. v. Eli Lilly & Co., 598 F.3d 1336, 1350 (Fed. Cir. 2010)).
[viii] Id. at 5.
[ix] Id. at 6.
[x] Id. at 7.
[xi] Id. at 7-8.
[xii] Id. at 8.
[xiii] Id. at 9.
[xiv] Id. at 10.
[xv] Id. at 11 (citing Ariad Pharms., Inc., 598 F.3d at 1353).
[xvi] Id. at 11, 13.
[xvii] Id. at 13
[xviii] Id. at 14
[xix] Id. at 14 (citing SAP Am., Inc. v. InvestPic, LLC, 898 F.3d 1161, 1167 (Fed Cir. 2018)). See, also, Id. at 14-15 (“[I]n the context of claims to results, we have explained that claims that ‘simply demand[] the production of a desired result . . . without any limitation on how to produce that result’ are directed to an abstract idea.” In re Killian, 45 F.4th 1373, 1382 (Fed. Cir. 2022) (quoting Interval Licensing LLC v. AOL, Inc., 896 F.3d 1335, 1345 (Fed. Cir. 2018)); see also Am. Axle & Mfg., Inc. v. Neapco Holdings LLC, 967 F.3d 1285, 1292 (Fed. Cir. 2020)).
[xx] Id. at 15. See also, Natural Alternatives Int’l, Inc. v. Creative Compounds, LLC, 918 F.3d 1338, 1343–44 (Fed. Cir. 2019) (“treatment claims . . . cover using a natural product in unnatural quantities to alter a patient’s natural state, to treat a patient with specific dosages outlined in the patents”).
[xxi] 35 U.S.C. §112(a).
