Sweegen, Inv. v. PureCircle USA Inc., et al.
IPR2019-01017 (US 9,243,273B2)
October 24, 2019
Decision not to institute IPR
Brief Summary: Petition for IPR denied as PTAB determined Sweegen did not present a reasonable likelihood of prevailing on obviousness or anticipation grounds.
Summary: Sweegen petitioned for IPR of PureCircle’s US 9,243,273B2 directed to methods for preparing steviol glycosides from other steviol glycosides (i.e., Revaudioside X (“Reb X”) from Revaudioside D (“Reb D”) using a UDP-glycosyltransferase (“UGT”) enzyme (e.g., UGT76G1) where “the conversion…is at least about 50% complete”). The Reb D to Reb X conversion occurs “through the addition of a glucose unit to the disaccharide at the C19 position of Reb D” (illustrated on p. 4 of decision and Fig. 2 of the ‘273 patent). Sweegen alleged obviousness over Ohta (a non-patent publication) in view of WO378 (WO 2011/153378A1) and over WO227 (WO 2014/122227A2). Sweegen argued the Ohta disclosed C19 is “essential for sweetness”, that RebX “possesses [a] superior taste profile”, a reasonable expectation of success in using a UGT enzyme to convert Reb D to Reb X (from WO378), and that “increasing the conversion” (to “at least about 50% complete”) “would have required only routine optimization.” PureCircle argued (with expert testimony) that “at the time of the invention, Reb X was not a compound of interest because Ohta showed that Reb X was only present in small amounts in” the plants studied, Ohta’s observed “slightly latent sweetness’…is a negative characteristic because rapid onset sweetness (as in natural sugars) is preferred”, Sweegen’s “calculated conversion rate of Reb D to Reb X as disclosed in Ohta is incorrect”, “it was an ‘open question’ as to whether the UDP-glycosyltransferases would be efficient at the C-19 position and, thus, ‘there was no reasonable expectation of success’”, and the claimed reaction “is an entirely different reaction from the reactions disclosed in WO378”. The PTAB concluded that Sweegen did not “present[] sufficient information to show that there was a motivation to combine Ohta with WO378” (InTouch Techs., FC 2014) or a reasonable expectation of success (e.g., “We are not persuaded that Dr. Walter’s calculated 32.3% conversion rate…is correct.”) The PTAB was also “not persuaded…that achieving at least about 50% conversion…would have required only routine experimentation and optimization” (e.g., WO378 shows UGT testing with different compounds, “not for converting Reb D to Reb X”). Sweegen also alleged obviousness in view of WO227, arguing that “WO227 is entitled to the effective filing date of its provisional application, and the ‘272 patent is not entitled to the effective filing date of its provisional application.” The PTAB explained that “[a] threshold issue” here was whether Sweegen had “met its initial burden to show that WO227 is prior art”, and the PTAB agreed regarding WO227 (“provisional provides a sufficiently enabling written description”) but not the ‘272 patent (e.g., “provisional describes the invention in ‘sufficient detail’ such that ‘one skilled in the art can clearly conclude that the inventor invented the claimed invention as of the filing date sought” (Tech. Licensing, FC 2008; Dynamic Drinkware, FC 2015; In re Gosteli, FC 1989). As WO227 was concluded not to be prior art, the PTAB also found no anticipation by WO227.