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Overlapping Ranges Give Rise to Presumption of Obviousness in IPRs

Addressing obviousness in inter partes reviews (IPRs), the US Court of Appeals for the Federal Circuit reversed the Patent Trial and Appeal Board (PTAB) and held a patent invalid for obviousness where claim limitations reciting ranges overlapped with ranges disclosed in the prior art. E.I. DuPont de Nemours & Co. v. Synvina C.V.Case No. 17-1977 (Fed. Cir. Sep. 17, 2018) (Lourie, J).

Synvina holds a patent on a method for preparing a certain chemical that has been recognized as having great potential in the “green” chemical industry. The claimed method recites four relevant reaction conditions:

  • A temperature between 140°C and 200°C

  • An oxygen partial pressure (PO2) of 1 to 10 bar

  • A solvent comprising acetic acid

  • A catalyst comprising cobalt, manganese and bromine

The reaction and its product were known in the prior art, but the three asserted prior art references disclosing the reaction use slightly different reaction conditions. Nonetheless, the prior art discloses ranges that include the claimed ranges and, in some instances, preferred ranges that include, or are about, the claimed ranges.

DuPont challenged the patent in an IPR, and the PTAB concluded in its final written decision that the claims of Synvina’s patent were not invalid for obviousness. The PTAB rejected DuPont’s contention that a burden-shifting framework applied because of the overlap between the claimed and prior-art ranges. The PTAB also found that DuPont had failed to show that temperature and PO2 were result-effective variables. Consequently, the PTAB concluded that a person of ordinary skill would not have been motivated to experiment with temperature and PO2 in order to optimize the yield of the reaction. Finally, although it found the claims not obvious, the PTAB found that Synvina’s evidence of secondary considerations was unpersuasive because the allegedly unexpected results arising from the claimed reaction conditions were found using one specific set of conditions that did not adequately address the full scope of the claimed ranges. DuPont appealed.

In the appeal, Synvina raised the issue of DuPont’s Art. III standing. Although DuPont had not been accused of infringement, the Federal Circuit, citing its recent JTEKT decision (IP Update, Vol. 21, No. 9) found the injury-in-fact requirement satisfied because DuPont had set up a commercial plant capable of operating in an infringing manner, and Synvina had rejected DuPont’s request for a covenant not to sue. 

On the merits, the Federal Circuit explained that where patent claims recite ranges that overlap with ranges disclosed in the prior art, the burden-shifting framework that applies in district court litigation and patent examination also applies in IPRs. Although DuPont retained the ultimate burden of persuasion, Synvina had the burden to produce evidence supporting either criticality of the claimed range or that the prior art taught away from the claimed range. The Court found that Synvina had failed to carry that burden. Further, the Court took a broad view of what constitutes recognition in the prior art that a variable is result-effective. It explained that the prior art in this case did disclose that temperature and PO2 were result-effective and that the PTAB had erred in concluding otherwise. Accordingly, the Court also found error in the PTAB’s holding regarding motivation to combine; because temperature and PO2 are result-effective variables, persons of ordinary skill would naturally be motivated to optimize them.

Finally, the Federal Circuit found that the PTAB’s conclusions regarding secondary consideration were supported by substantial evidence. On those bases, the Court held that the claims at issue were obvious.

Practice Note: Validity analysis applied in IPRs should conform to the analysis used in other contexts. Practitioners should read any cases that appear to create special rules for America Invents Act reviews narrowly.

© 2020 McDermott Will & Emery


About this Author


David Mlaver* is an associate in the law firm of McDermott Will & Emery LLP and is based in the Firm’s Washington, D.C. office.  He focuses his practice on intellectual property litigation matters.

David received his J.D., cum laude, from the Georgetown University Law Center, where he was a senior editor of The Tax Lawyer.  He earned his A.B. in chemistry and B.S. in biology, with high distinction, from Duke University. David is admitted to practice in Maryland.

*Not admitted to practice in the District of Columbia...

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