Last week, in In re Ikeda Food Research Co., the Federal Circuit affirmed a decision by the U.S. Patent and Trademark Office Patent Trial and Appeal Board affirming the Examiner's rejection in an ex parte reexamination of claims 22 and 23 of U.S. Application No. 12/851,668 for obviousness. On appeal before the Board, the challenged claims were found obvious in view of three references: European Patent Application Publication No. 0 094 161 ("Senior") and U.S. Patent Nos. 6,656,702 ("Yugawa A") and 6,059,946 ("Yugawa B").
Claim 22 of the '668 application recites (with emphasis in the opinion):
A biosensor for measuring glucose, comprising:
an electrode system comprising an action electrode and a counter electrode; and
an enzymatic reaction layer in contact with the action electrode and/or the counter electrode, the enzymatic reaction layer comprising an electron acceptor and a soluble [f]lavin compound-binding glucose dehydrogenase, which has enzymatic activity to glucose comprising catalyzing a reaction for oxidizing glucose in the presence of the electron acceptor,
wherein enzymatic activity to maltose in the enzymatic reaction layer is 5% or less relative to the enzymatic activity to glucose;
wherein the biosensor can quantify glucose concentrations ranging from 4.5 mM to 30 mM.
According to the opinion:
The '668 application purports to improve upon the prior art by claiming use of, inter alia, a specific enzyme: a "flavin"-dependent GDH ("FAD-GDH") designated as Enzyme Commission ("E.C.") 1.1.99.10, whose "relative reactivity" (or "substrate specificity"), was found to exhibit "high activity" on glucose, and "low activity" on the seventeen other substrates tested, including maltose.
In the ex parte reexamination of the '668 application, the Examiner rejected claims 22 and 23 in view of the combination of Senior, which discloses a qualitative procedure for determining blood glucose concentration using a FAD-GDH enzyme derived from a strain of A. orzyae, which like the FAD-GDH enzyme described in the '668 application (which was isolated from a different microorganism) is designated E.C. 1.1.99.10, and Yugawa A and B, which disclose a biosensor. (The opinion explains that E.C. numbers, which are promulgated by the Enzyme Commission, provide a common classification scheme for enzymes based on the chemical reactions they catalyze, and notes that "Ikeda's counsel does not dispute that enzymes with the same E.C. number have the same substrate specificity 'for purposes of this appeal.'")
The Board affirmed the Examiner's rejection, determining that even though Senior did not expressly disclose the low-maltose activity limitation of claim 22 of the '668 application, the enzyme preparation disclosed in Senior inherently contains the same enzymatic specificity for glucose relative to maltose as the challenged claims in the '668 application. More particularly, the Board concluded that it was reasonable to infer the FAD-GDH enzymes disclosed in Senior and the '668 application have the same low substrate specificity for glucose relative to maltose because both Senior and the '668 application classify the FAD-GDH enzymes in their enzyme preparations as E.C. 1.1.99.10.
On appeal before the Federal Circuit, Ikeda argued that the Board erred by relying upon inherency to supply the necessary low-maltose activity claim element in making its obviousness determination, by improperly shifting the evidentiary burden to Ikeda, and by discounting the objective indicia of nonobviousness, specifically that of a long-felt need. With respect to its first argument, Ikeda contended that because Senior's enzyme preparation was contaminated with about 7,000 times more protein than the '668 application's preparation, those impurities caused Senior's preparation to "differ[] vastly" from the '668 application's preparation in how it reacts with maltose. The Federal Circuit, however, disagreed with Ikeda's argument, finding that "[s]ubstantial evidence supports the PTAB's conclusion that Senior's FAD-GDH enzyme preparation inherently discloses the Challenged Claims' low-maltose activity limitation." In particular, the opinion states that "[a]lthough Senior does not directly address glucose specificity or maltose, Senior's FAD-GDH enzyme, prepared from 'A[.] oryzae,' has the same 'E.C. 1.1.99.10' classification number as the '668 application's FAD-GDH enzyme, even though each FAD-GDH enzyme is produced from a different microorganism, i.e., from 'A. Terreus'" [citations omitted]. The opinion concludes that "it was reasonable for the PTAB to conclude that both Senior and the '668 application characterize their microbe-derived preparations as having identical enzymatic activity, which necessarily includes having the same substrate specificity" (emphasis in opinion), adding that:
The PTAB had a reasonable basis to conclude that because Senior discloses the use of the FAD-GDH enzyme described in the '668 application, classified under E.C. 1.1.99.10, the claimed low "5% or less" activity against maltose relative to glucose in the reaction layer is inherently disclosed in Senior's enzyme preparation.
The Federal Circuit also rejected the argument that the Board improperly shifted the evidentiary burden to Ikeda, citing In re Best, 562 F.2d 1252, 1255 (CCPA 1997), for the proposition that "the fairness of shifting the burden 'is evidenced by the [US]PTO's inability to manufacture products or to obtain and compare prior art products.'" The Court therefore concluded that "we see no reason to call into question the PTAB's finding 'that the 'possible presence of contaminants' in Senior's enzyme preparation [does not] render the claimed biosensor non-obvious.'"
Finally, with respect to Ikeda's argument that the Board discounted the objective indicia of nonobviousness, especially that of a long-felt need, the Federal Circuit disagreed that the Board erred by not crediting Ikeda's evidence of long-felt need for a GDH enzyme with no separate cofactor. The Court noted that because claim 22 employs the transitional phrase "comprising" in its preamble, the claim "does not exclude biosensors that employ a cofactor" (emphasis in opinion). Therefore, because claims 22 and 23 encompass biosensors that use cofactors, "it follows that they do not satisfy Ikeda's alleged need for dehydrogenase-based glucose sensors that do not rely on a cofactor." Rejecting all of Ikeda's arguments, the Federal Circuit therefore affirmed the decision of the Patent Trial and Appeal Board.
In re Ikeda Food Research Co. (Fed. Cir. 2019)
Nonprecedential disposition
Panel: Circuit Judges Wallach, Taranto, and Hughes
Opinion by Circuit Judge Wallach
