Ikeda Food Research Co., Ltd. et al.

Patent Trials and Appeals Board

Feb 23, 2022

2021001853 (P.T.A.B. Feb. 23, 2022)

UNITED STATES PATENT AND TRADEMARK OFFICE UNITED STATES DEPARTMENT OF COMMERCE United States Patent and Trademark Office Address: COMMISSIONER FOR PATENTS P.O. Box 1450 Alexandria, Virginia 22313-1450 www.uspto.gov APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO. 16/278,025 02/15/2019 Hironori OMURA 43111/0005 8483 1912 7590 02/23/2022 AMSTER, ROTHSTEIN & EBENSTEIN LLP 90 PARK AVENUE NEW YORK, NY 10016 EXAMINER LIU, SAMUEL W ART UNIT PAPER NUMBER 1656 MAIL DATE DELIVERY MODE 02/23/2022 PAPER Please find below and/or attached an Office communication concerning this application or proceeding. The time period for reply, if any, is set in the attached communication. PTOL-90A (Rev. 04/07) UNITED STATES PATENT AND TRADEMARK OFFICE ____________ BEFORE THE PATENT TRIAL AND APPEAL BOARD ____________ Ex parte HIRONORI OMURA, HIROKAZU SANADA, TAKAKO YADA, TETSUNARI MORITA, MIKA KUYAMA, TOKUJI IKEDA, KENJI KANO, and SEIYA TSUJIMURA ____________ Appeal 2021-001853 Application 16/278,0251 Technology Center 1600 ____________ Before TAWEN CHANG, RACHEL H. TOWNSEND, and DAVID COTTA, Administrative Patent Judges. COTTA, Administrative Patent Judge. DECISION ON APPEAL This is an appeal under 35 U.S.C. § 134 involving claims to a method for producing a biosensor for measuring glucose in a sample liquid. The Examiner rejected the claims on appeal under 35 U.S.C. § 103(a) as obvious, and, provisionally, under 35 U.S.C. § 101 on the ground of double patenting. We REVERSE. 1 We use the word “Appellant” to refer to “applicant” as defined in 37 C.F.R. § 1.42. According to Appellant, the real parties in interest are Ikeda Food Research Co., Ltd, which is a subsidiary of Ikeda Tohka Industries, Co., Ltd., and PHC Corporation, a subsidiary of PHC Holdings Corporation. Appeal Br. 3. Appeal 2021-001853 Application 16/278,025 2 STATEMENT OF THE CASE The Specification teaches that the presence of glucose in blood is “an important marker for diabetes.” Spec. 1. The Specification further teaches that “a method for measuring a blood sugar and a means for controlling the blood sugar level are desired which can be utilized not only in a hospital but also at home and which is convenient.” Id. at 2. In response to this need, “an objective of the invention is to provide a novel glucose dehydrogenase which exhibits an excellent substrate-recognizing ability toward glucose and which has low activity on maltose, and also to provide a method for producing the same and a microorganism having an ability of producing the same.” Id. at 4. “Another objective of the invention is to provide [an] excellent glucose measuring method, measuring reagent and biosensor which employ the novel glucose dehydrogenase and which are capable of quantifying glucose rapidly and conveniently at a high accuracy, as well as a glucose- eliminating reagent.” Id. The Specification explains that “[t]he inventors . . . made an effort in characterizing various microorganisms producing the coenzyme-binding glucose dehydrogenase, and finally discovered a coenzyme-binding glucose dehydrogenase-producing microorganism and a coenzyme-binding glucose dehydrogenase.” Id. at 4-5. “The coenzyme-binding glucose dehydrogenase has a physicochemical ability of catalyzing a reaction for oxidizing glucose, especially a hydroxyl group in the 1st-position of glucose, in the presence of an electron acceptor.” Id. at 5. “The invention provides a biosensor employing the novel soluble coenzyme-binding glucose dehydrogenase and a biosensor capable of quantifying and/or qualifying a particular component in a sample.” Id. at 7. Appeal 2021-001853 Application 16/278,025 3 Claims 23 and 24 are on appeal. Claim 23 is representative and reads as follows: 23. A method for producing a biosensor for measuring glucose in a sample liquid comprising: (i) obtaining a soluble flavin adenine dinucleotide- binding glucose dehydrogenase (FAD-GDH) secreted from an Aspergillus fungal body, which has enzymatic activity to glucose comprising catalyzing a reaction for oxidizing glucose in the presence of an electron acceptor, and (ii) forming a biosensor comprising an electrode system and an enzymatic reaction layer on an electrode of the electrode system, the enzymatic reaction layer comprising the soluble flavin adenine dinucleotide-binding glucose dehydrogenase and an electron acceptor, wherein: (a) enzymatic activity of the FAD-GDH to maltose is 5% or less relative to the enzymatic activity of the FAD-GDH to glucose, and (b) enzymatic activity of the FAD- GDH to D-fructose is not more than the enzymatic activity of the FAD-GDH to maltose. Appeal Br. 21. The claims stand rejected as follows: Claims 23 and 24 were rejected under 35 U.S.C. § 103(a) as obvious over the combination of Senior,2 Yugawa A,3 Yukawa B.4 Claims 23 and 24 were provisionally rejected under 35 U.S.C. § 101 on the ground of double patenting over claims 23 and 24 of U.S. Patent Application No. 16/278,008 (now US Patent No. 10,988,738). 2 Senior et al., EP 0 094 161, published Nov. 16, 1983 (“Senior”). 3 Yugawa et al., US Patent No. 6,656,702 B1, issued Dec. 2, 2003 (“Yugawa A”). 4 Yukawa et al., US Patent No. 6,059,946, issued May 9, 2000 (“Yukawa B”). Appeal 2021-001853 Application 16/278,025 4 OBVIOUSNESS Claim 23 requires that the enzymatic activity of the recited FAD-GDH with respect to maltose be 5% or less than its activity with respect to glucose and that its activity with respect to D-fructose not exceed its activity with respect to maltose. In finding claim 23 obvious, the Examiner reasons that the FAD-GDH enzyme descried in the Specification and that described in Senior are both “derived from an Aspergillus species.” Ans. 9-10. The Examiner further reasons that “both the prior art (Senior) and [the] instant invention use the identical GDH enzyme of E.C. [Enzyme Commission] 1.1.99.10 . . . and thus, the claimed property, i.e., relative enzymatic activity (relative to glucose) [substrate specificity] to maltose in the enzymatic reaction layer (claim 23, lines 7-8) even if not stated in Senior reference, would be inherent.” Ans. 5 (emphasis omitted). As support, the Examiner points to two examples of enzymes classified as EC No. 1.1.99.10 and derived from species of Aspergillus that were reported to have the claimed relative enzyme activities: 1) the teaching reported in Table 1 of the Specification, and 2) the teaching in the Sekisui Brochure5 of an enzyme derived from an unidentified Aspergillus species having the claimed relative enzyme activity. Ans. 5, 10. Appellant argues that the evidence relied upon by the Examiner does not establish that Senior’s FAD-GDH, classified as EC No. 1.1.99.10, necessarily has the claimed relative enzyme activities. See generally Appeal Br. We agree. 5 Sekisui Diagnostic, LLC, Enzymes: Glucose Dehydrogenase FAD Dependent, copyright 2017 (“Sekisui Brochure”). Appeal 2021-001853 Application 16/278,025 5 Table 1 of the Specification sets forth the substrate specificity, including secondary substrate specificity, and relative activity of one enzyme within the EC 1.1.99.10 classification, i.e., the coenzyme-binding glucose dehydrogenase derived from the Aspergillus terreus microorganism designated “97508” and deposited under FERM BP-08578. Spec. 27:8-29, 31:3-15, 39:1-2, 39:24-41:24, 42:1-4, 44:2-4, 45 (Table 1). Similarly, Sekisui sets forth the substrate specificity and relative activity of one FAD- GDH enzyme derived from an unidentified Aspergillus species and having the EC 1.1.99.10 classification. Sekisui 1-2.6 Although both of these enzymes have the same EC classification, the claimed substrate specificity for glucose, and similar relative activities for other sugars, this does not establish that the enzyme described in Senior necessarily has the claimed specificities. Indeed, Dr. Masaaki Kotera, who is a member of the committee that sets the rules by which enzymes are classified by Enzyme Commission Number, testifies that the classification of two enzymes under the same EC Number does not mean that those enzymes necessarily have the same relative activity. See generally Kotera Decl.7 More particularly, Dr. Kotera explains that EC Numbers classify enzymes by the primary reaction they catalyze. Id. ¶ 6. If two different enzymes “catalyze the same primary chemical reaction, then they will be classified in the same EC number.” Id. In the case of EC 1.1.99.10, the primary reaction 6 Sekisui is not paginated. Therefore, we refer to page numbers as if the document was numbered consecutively starting with the first page. 7 Declaration of Dr. Masaaki Kotera under 37 C.F.R. § 1.132, signed Oct. 9, 2019 (“Kotera Declaration” or “Kotera Decl.”). The Kotera Declaration was originally filed in connection with US Patent Application No. 16/278,030. It was filed in the present application with the Information Disclosure Statement filed on August 27, 2020. Appeal 2021-001853 Application 16/278,025 6 being catalyzed is “D-glucose + acceptor <=> D-Glucono-1,5-lactone + reduced acceptor.” Id. ¶ 8. However, “[c]lassification of an enzyme in EC 1.1.99.10 does not mean the enzyme is specific only for D-glucose.” Id. ¶ 9.8 Enzymes classified as EC 1.1.99.10 may have specificity for one or more secondary substrates. Id. If they do, “one cannot tell from the EC 1.1.99.10 classification (1) what the secondary substrates are or (2) the number of secondary substrates that the enzyme has specificity for.” Id. Dr. Kotera cites to Table 4 of the Amano Application,9 which is reproduced below, as an example of enzymes classified under the same EC number but having different substrate specificities. Id. Amano Application ¶ 143. Table 4 provides the specificities of FAD-GDH derived from seven different strains of Aspergillus oryzae for the following substrates: glucose, 2-deoxyglucose, xylose, fructose, mannose, and maltose. Id. As can be seen, the substrate specificities for the seven FAD-GDH 8 Dr. Kotera distinguishes between enzyme specificity and enzyme activity. “Specificity of an enzyme refers to how restrictive the enzyme is in its choice of substrate.” Kotera Decl. ¶ 5. “Activity, on the other hand, is a quantitative measure of the catalytic action of an enzyme on a given substrate.” Id. 9 US Patent Publication No. 2009/0181408 A1, published July 16, 2009 (“Amano Application”). Appeal 2021-001853 Application 16/278,025 7 enzymes are not identical. Id. Accordingly, we agree with Dr. Kotera that “Table 4 of the Amano Application is a good example showing that enzymes from different sources classified in EC 1.1.99.10 can have different [specificity for different] secondary substrates with different activities.” Kotera Decl. ¶ 9. Further, according to Dr. Kotera, “[c]lassification of an enzyme in EC 1.1.99.10 does not mean that the enzyme has the same level of activity on D- glucose as any other enzyme classified in EC 1.1.99.10.” Id. ¶ 10. Thus, although “all enzymes classified in EC 1.1.99.10 will catalyze the glucose dehydrogenating reaction, the activity level of each enzyme may be different.” Id. In sum, according to Dr. Kotera, “the classification of an enzyme in EC 1.1.99.10 provides no information about the enzyme’s possible specificity for any secondary substrate and no information about the enzyme’s activity level on any possible secondary substrates.” Id. ¶ 11. Particularly in view of Dr. Kotera’s testimony, the Examiner has not persuaded us that every enzyme classified as EC 1.1.99.10 and derived from an Aspergillus species will have the claimed relative activity to glucose, maltose, and D-fructose. Accordingly, although it is possible that Senior’s FAD-GDH has the claimed relative activity to these substrates, the Examiner has not persuasively established that it necessarily has these properties, as is required to support the Examiner’s position that such activities are inherently present in Senior’s enzyme. See In re Robertson, 169 F.3d 743, 745 (Fed. Cir. 1999) (“Inherency, however, may not be established by probabilities or possibilities. The mere fact that a certain thing may result from a given set of circumstances is not sufficient.”). Appeal 2021-001853 Application 16/278,025 8 We recognize that we found, in an appeal involving a related application, that Senior’s classification of its enzyme as EC 1.1.99.10 provided “a reasonable basis for expecting Senior’s GDH to have the same properties as the claimed GDH.” Ex parte Hironori Omura et al., Appeal No. 2015-002637, at 10 (PTAB July 28, 2017). In that case, however, Appellant did not dispute the Examiner’s finding that enzymes having the same EC Number had the same relative activities. See id. at 6 (“The Examiner finds, and Appellants do not dispute that ‘[t]wo enzymes having [the] identical EC number necessarily possess identical enzymatic activity including ‘substrate specificity.’”); see also In re Ikeda Food Research Co., Ltd., 758 F. App’x 952, 957 (Fed. Cir. 2019) (affirming Board’s decision, noting 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’”). Here, not only does Appellant dispute that enzymes with the same EC number have the same substrate specificity, Appellant provides persuasive evidence to the contrary. Accordingly, we reverse the Examiner’s rejection of claims 23 and 24 as obvious. DOUBLE PATENTING Claims 23 and 24 were provisionally rejected under 35 U.S.C. § 101 as claiming the same invention as that of claims 23 and 24 of copending Application No. 16/278,008 (“the ’008 application”) now US Patent No. 10,988,738). In rejecting these claims , the Examiner found that the only difference between independent claim 23 and the reference claim was that the reference claim recites that the “enzymatic activity of the FAD-GDH to D-fructose is not more than the enzymatic activity of the FAD-GDH to D- mannose” while claim 23 recites that the “enzymatic activity to D-fructose Appeal 2021-001853 Application 16/278,025 9 is not more than enzymatic activity of the FAD-GDH to maltose.” Ans. 8. The Examiner finds that the claims recite the same enzyme based on the premise that “enzymes with EC 1.1.99.10 inherently have[] identical enzymatic activity and substrate specificity.” Ans. 13. For the reasons discussed above, the evidence of record does not support that all enzymes classified as EC 1.1.99.10 have the same specificity or activity level with respect to secondary substrates like maltose and D-mannose. Accordingly, we reverse the Examiner’s provisional rejection of claims 23 and 24 on the ground of double patenting. CONCLUSION In summary: Claims Rejected 35 U.S.C. § Reference(s)/Basis Affirmed Reversed 23, 24 103(a) Senior, Yugawa A, Yukawa B 23, 24 23, 24 101 Provisional Statutory Double Patenting Application No. 16/278,008 23, 24 Overall Outcome 23, 24 REVERSED