N OTE : This disposition is nonprecedential. 

# United States **Court of Appeals**  **for the Federal Circuit**

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IN RE: IKEDA FOOD R ESEARCH CO., LTD., Appellant

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2017

- 2624

______________________ Appeal from the United States Patent and Trademark Office, Patent Trial and Appeal Board in No. 12/851,668.

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Decided: January 29, 2019

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T HOMAS H. J ENKINS , Finnegan, Henderson, Farabow, Garrett & Dunner, LLP, Washington, DC, argued for appellant. Also represented by M ICHAEL P AUL B ARKER , M ICHAEL L IU S U , Palo Alto, CA.

S ARAH E. C RAVEN , Office of the Solicitor, United States Patent and Trade mark Office, Alexandria, VA, argued for appellee Andrei Iancu. Also represented by T HOMAS W. K RAUSE , K AKOLI C APRIHAN

.

______________________
Before W ALLACH , T ARANTO , and H UGHES , Circuit Judges.

W ALLACH , Circuit Judge

. Appellant Ikeda Food Research Co., Ltd. (“Ikeda”) a ppeals a decision on appeal of the U.S. Patent and Trad e-IN RE : I KEDA F OOD RESEARCH CO ., LTD

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mark Office’s (“ US PTO”) Patent Trial and Appeal Board (“PTAB”) in an ex parte reexamination affirming an examiner’s rejection of, inter alia, claims 22−23 (“the C hallen ged Claims”) of U.S. Patent Application No. 12/851,668 (“the ’668 application” ) (J.A. 837

– 99 ) as obv ious pursuant to 35 U.S.C. § 103(a) (2006). 1 See In re I

keda Food Research Co. , No. 2015

- 002637 (P.T.A.B. July 28, 2017) (J.A. 2– 17). We have jurisdiction pursuant to 28 U.S.C. § 1295(a)(4)(A) (2012). We affirm.

B ACKGROUND
I. The ’ 668 Application

Entitled “ Coenzyme

- Binding Glucose Dehydrogenase ,” the ’668 a pplication generally relates to a “ convenient ” method for patients to reg ularly measur e and monitor their blood glucose , i.e., blood sugar, “ and a means for controlling the blood sugar level

. . . which can be utilized not only in a hospital but also at home .” J.A. 839. The enzymatic method employs blood glucose “biosensors,” 2

1 Congress amended § 103 when it enacted the Leahy

- Smith America Invents Act (“ AIA ”) . Pub. L. No. 112

- 29, § 3(c), 125 Stat. 284, 287 (2011)

. However, b ecause the ’668 application never contained a claim having an effective filing date on or after March 16, 2013 (the effective date of the statutory changes enacted in 2011), or a reference under 35 U.S.C. §§ 120, 121, or 365(c) to any patent or application that ever contained such a claim, the pre

- AIA § 103 applies. See id. § 3(n)(1), 125 Stat. at 293.

2 Biosensors co mmonly rely on enzymes, with the most commonly used enzymes being those that catalyze (cause or accelerate) oxidation

- reduction reactions. See J. A. 356. Such enzymes include glucose oxidases (“GOx”) and glucose dehydrogenases (“GDH”), the latter of which includes enzymes that use nicotinamide adenine dinucle o-IN RE : I KEDA F OOD RESEARCH CO ., LTD

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J.A. 839, as “an important marker for diabetes ,” J.A. 838. The ’668 application describe s prior art methods that use “a biosensor employing a [GDH] ” and exhibit various disadvantages

, such as “high background noise” that leads to erratic readings “due to a level of residual ox ygen,” and “a complicated reaction system” that is “ expe ns ive .” J.A. 839

– 40

. T he ’668 application purports to improve upon the prior art by claiming use of , inter alia, a specific enzyme : a “f lavin ”- dependent GDH (“FAD

- GDH”) designated as Enzyme Commission (“ E.C. ”) 3 1.1.99.10, J.A. 890, whose “ relativ e reactivity ” (or “substrate spec ificity”)

, was found to exhibit “high activity” on glucose, and “low activity” on the seventeen other substrates tested, including ma ltose

, see J.A. 864 −65

. The “objective of the invention is to provide a novel [GDH] which exhibits an excellent substrate

- recognizing ability toward glucose and which has low activity on maltose

, [ 4 ] and also to provide a method for producing the same and a microorganism having an ability of producing the same.” J.A. 841. T he newly

- discovered “ coenzyme

binding [GDH] has [the] ability of catalyzing a reaction for oxidizing glucose, especially a hydroxyl group in the

tide (“ NAD (P) + ”) or pyrroloquinoline quinone (“PQQ”) as an expensive and unstable cofactor s

. See J.A. 356, 838−40, 843.

3 E.C. numbers are promulgated by the Enzyme Commission, J.A. 176, and provide a common classific ation scheme for enzymes based on the chemical reactions they catalyze

, s ee J.A. 7− 8.

4 Maltose is “a sugar produced by the b reakdown of starch,” and enzymes that have intrinsic enzymatic activity towards maltose, such as PQQ

- GDH, were later reported to pose high risks for patients on infusion drugs. J.A. 269; see J.A. 840−41 (excerpts from another utility patent application).IN RE : I KEDA F OOD RESEARCH CO ., LTD

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[first] position of glucose, in the presence of an electron

accep tor. ” J.A. 842. To obtain the FAD

- GDH enzyme, a microorganism (or microbe) containing the enzyme is first

“ cultured ,” and the enzyme is “recovered from the culture by means of an ordinary protein purification method .” J.A. 8 64, 86 9. T he ’668 application recounts the purified enzyme’s activity to maltose as 1.4%
, relat ive to its activ ity to glucose , which is regarded as 100%. See J.A. 882 (Table 1) ; see also J.A. 845 (descri bing the graphical data quantifying various activity of the coenzyme

- binding GDHs )

. According ly, the purified FAD

- GDH enzyme is

use d in prior

- art biosensors that comprise “ an action electrode, a counter electrode, ” and “ an enzymatic rea ction layer. ” J.A. 8 74

. Independent c laim 22 is representative of the Cha llenged Claims, and recites : 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 cou nter electrode, the enzymatic reaction layer comprising an electron acceptor and a so luble [f]lavin compound

- binding glucose dehydrogenase, which has enzymatic a ctivity to glucose comprising catalyzing a reaction for oxidizing glucose in the pre sence of the electron acceptor,

wherein enzymatic activity to maltose in the enzymatic reaction layer is 5% or less relative to the enzymatic activity to gl ucose ; wherein the biosensor can quantify gl ucose concentrations ranging from 4.5 mM to 30 mM



### .IN RE : I KEDA F OOD RESEARCH CO ., LTD

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J.A. 230 (emphasis added)

. II. The Prior Art References

A. Senior

Entitled “ Method for Determin in g Glucose Content of Fluid,” European Patent Application Publication No. 0094161 (“Senior”) (J.A. 283−300) discloses a qualit ative procedure for determining blood glucose concentr ation

, preferably using either a FAD

- GDH enzyme derived from a strain of A . orzyae, which is a different microo rganism than the ’668 application’s FAD

- GDH enzyme yet similarly designated E.C. 1.1.99.10
, or a PQQ

- GDH
enzyme which is designated E.C. 1.1.99.17. See J.A

. 283 (“A method for determining glucose present in a fluid wherein a sample of a glucose

- containing fluid is contac ted with an assay mixture com prising .

. . flavin

- dependent glucose dehydrogenase enzyme E.C. 1.1.99.10 and a reducible compound, reduction of which can produce changes in electro

- magnetic radiation absorbance chara cteristics and/or electrical changes .”)

, 287 ( discussing “ a preferred source of E.C. 1.1.99.17 ” as the second enzyme)

. Senior states that the FAD

- GDH enzyme it employs “need not be purified to an excessively high standard” and that the P QQ

- GDH has some “lesser activity on other sugars. ” J.A. 289.

B. The Yugawa Patents

Related U.S. Patent No s . 6,656,702 (“Yugawa A”) and 6,059,946 (“Yugawa B”) (collectively

, “ the Yugawa p atent s ”) disclose “ a biosensor ” comprising , inter alia, an

“ electrode system ” with a “ working electrode, ” “ counter electrode,” and “ a reaction layer. ” Yugawa A col. 2 ll. 3−7;

see Yugawa B col. 2 ll. 4−8 (same)

. The enzymes used in the reaction layer specifically include GDH and PQQ

GDH. Yugawa A col . 2 ll. 8−15; Yugawa B col. 5 l. 45. The Yugawa patents also describe stability and cost advantages of their biosensor similar to those described inIN RE : I KEDA F OOD RESEARCH CO ., LTD

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the ’668 appli cation

. Compare Yugawa A col. 1 l. 63

– col. 2 l. 2

, and Yugawa B col. 1 l l . 66−67
, with J.A. 84 0– 41

. D ISCUSSION I. Standard of Review and Legal Standard “We review the PTAB’s factual findings for substa ntial evidence and its legal conclusions de novo.” Re dline Detection, LLC v. Star Envirotech, Inc. , 811 F.3d 435, 449 (Fed. Cir. 2015) (citation omitted). “Substantial evidence is something less than the weight of the evidence but more than a mere scintilla of evidence,” meaning that “[i ]t is such relevant evidence as a reasonable mind might accept as adequate to support a conclusion.” In re NuVasive

, Inc. , 842 F.3d 1376, 1379

– 80 (Fed. Cir. 2016) (inte rnal quotation marks and citations omitted). “If two inconsistent conclusions may reas onably be drawn from the evidence in record, the PTAB’s decision to favor one conclusion over the other is the epitome of a decision that must be sustained upon review for substantial evidence.” Elbit Sys. of Am., LLC v. Thales Visionix, Inc. , 881 F.3d 13 54, 1357 (Fed. Cir. 2018) (internal quotation marks, brackets, and citation omitted). A patent claim is invalid “if the differences between the subject matter sought to be patented and the prior art are such that the subject matter as a whole would have be en obvious at the time the invention was made to a person having ordinary skill in the art [ (‘ PHOSITA ’) ].” 35 U.S.C. § 103(a). Obviousness is a question of law based on underlying findings of fact. See In re Adler , 723 F.3d 1322, 1325 (Fed. Cir. 2013)

. Those underlying findings of fact include : (1) “the scope and content of the prior art,” (2) “differences between the prior art and the claims at issue,” (3) “the level of ordinary skill in the pertinent art,” and (4) the presence of objective indicia of nonobviou sness , such “as commercial success, long felt but unsolved needs, failure of others,” and unexpected results. Graham v. John Deere Co. of Kan. City , 383 U.S. 1, 17 (1966); seeIN RE : I KEDA F OOD RESEARCH CO ., LTD

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United States v. Adams , 383 U.S. 49, 50

– 52 (1966). For objective indicia of non

- obviousness, a showing that a problem was both recognized in the prior art and there existed a failure of others to provide “ a feasible solution to the long

- standing problem ” supports a finding of long

- felt need. In re Cyclobenzaprine Hydrochl oride

, 676 F.3d 1063, 1083 (Fed. Cir. 2012) (citation omitted). Further, “[a] n obviousness determination re quires finding that a [PHOSITA] would have been motivated to combine or modify the teachings in the prior art and would have had a reasonable expectation of success in doing so.” Regents of Uni v . of Cal. v. Broad Inst., Inc.

, 903 F.3d 1286
, 1291 (Fed. Cir. 201 8 ) (citation omitted).

“W e have recognized that inherency may supply a missing claim limitation in an obviousness analysis .” PAR Pharm., Inc. v. TWI Pharm., Inc., 773 F.3d 1186, 1194

– 95 (Fed. Cir. 2014) ; see id . at 1195 (collecting cases). However, “the limitation at issue necessarily must be present [] or the natural result of the combination of elements explicitly disclosed b y the prior art” to be inhe rently disclosed by the reference. Id

. ; see Southwire Co. v. Cerro Wire LLC , 870 F.3d 1306, 1311 (Fed. Cir. 2017) (requiring the PTAB to find that a reference disclosed an “identical or substantially identical” process to that claimed by the patent in order to find inheren t obviou sness ). W here “ all process limitations

. . . are expressly disclosed by [the prior art refer ence], except for the fun cti onally expressed [limitation at issue], th e [US] PTO can require an applicant to prove that the subject matter shown to be in the prior art does not possess the chara cteristic relied on.” Southwire , 870 F.3d at 1311 (internal quotation marks and citation o mitted).

II . Obviousness The PTAB affirmed the Examiner’s findings that e mploying the FAD

- GDH enzyme preparation described in Senior with the biosensor described in the Yugawa p a-IN RE : I KEDA F OOD RESEARCH CO ., LTD

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tents would have rendered the Challenged Claims obvious to a PHOSITA. See J.A . 9−10; see also J.A. 153−57 (E xaminer’s findings). In rendering its obviousness decision, the PTAB specifically determined that even though Senior did not expressly disclose the low

- maltose activity limit ation of claim 22 of the ’668 application , Senior’ s disclosed enzyme preparation inherently contain s the same enz ymatic specificity for glucose relative to maltose as the Challenged Claim s

. See J.A. 10; see also J.A. 10−11 ( relying on the undisputed fact that both Senior and the ’668 application classify the ir respective FAD

- GDH e nzyme in their enzyme preparations as E.C. 1.1.99.10
, and concluding that it was reasonable to infer they have the same low substrate specificity for glucose relative to maltose )

. The PTAB also disagreed with Ikeda that Ikeda’s proffered extrinsic evidence of another “contam inated” GDH preparation somehow established that Se nior’s enzyme preparation was likewise contaminated . J.A. 11− 12. Ikeda contends that “the PTAB erred in its prima facie case” by (1) relying upon inherency to supply the necessary low

- maltose activity claim element in making its obviousness determi nation, see Appellant ’ s Br. 30
, and (2) improperly shifting the evidentiary burden to Ikeda

, see id . at 33 . Ikeda also asserts that “the [PTAB] erred in discounting the objective indicia of nonobviousness,” especially that of a long

- felt need. Id . at 42 (capitalization modified). We address each argument in turn.

A

. Substantial Evidence Supports the PTAB’s Determin ation that t he Challenged Claims Would Have Been Obv ious o ver Senior and t he Yugawa Patents

Ikeda contests the PTAB’s determination that Se nior’s E.C. 1.1.99.10 FAD

- GDH enzyme preparation inhe rently discloses the Challenged Claims ’ limitation of a reaction layer with low reactivity toward maltose relative to glucose

, id . at 30
, but does not contest that each of theIN RE : I KEDA F OOD RESEARCH CO ., LTD

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other limitations are taught by this combination

, s ee generally id

. 5 Specifically, Ikeda argues that because “Senior’s enzyme preparation was contaminated with about 7,000 times more prot ein than the [’668 applic ation ]’s preparation,” these impurities cause Senior ’s preparation to “differ[] vastly” from the ’668 application’s preparation in how it react s with maltose. Appellant’ s Br. 31

. We disagree. Substantial evidence supports the PTAB’s conclusion that Senior’s FAD

- GDH enzyme preparation inherently discloses the Challenged Claims’ low

- maltose activity limitation

. Table 1 of t he ’668 application discloses that the E.C. 1.1.99.10 enzyme’s activity for maltose is 1.4% relative to its activity for glucose

. S ee J.A. 882 (reporting testing results in Table 1 that state that the FAD

- GDH enzyme preparation’s activity towards “maltose” is “1.4%” relative to its 100% activity towards glucose)

. Senior discloses an assay for determining blood glucose conce ntration and teaches , in relevant part, purifying a n FAD

GDH enzyme from a crude cellular extract. See J.A. 287

. Although Senior does not directly address glucos e specifi city or maltose

, s ee J.A. 283−300 , 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
, ” c ompare J .A. 2 87, 2 93
, with J.A. 843

. E.C. classification numbers are based on enzyme reactivity, s ee J.A. 176 (describing, in a scientific journal, the known

5 Ikeda also does not dispute the PTAB’s finding that the Yugawa patents ’ biosensor (compris ing “an insulating plate (layer), electrode system, and a reaction layer ,” J.A. 9), could be combined with Senior’s FAD

- GDH E.C. 1.1.99.10 enzyme to arrive at the C hallenged Claims’ biosensor, see generally Appellant’s Br

.IN RE : I KEDA F OOD RESEARCH CO ., LTD

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“genomics” and “chemical information” represented by E.C. classification number s ), and Ikeda’s counsel does not dispute that enzymes with the same E.C. number have the same substrate specificity “fo r purposes of this appeal,” Oral. Arg. at 6 :32 −: 47
, http://oralarguments.cafc.uscourts. gov/default.aspx?fl=2017

- 2624.mp3

. Therefore, it was reasonable for the PTAB to conclude that both Senior and the ’668 application character ize their m i crobe

- derived
prepara tions as having identical enzymatic activity

, which necessarily includes having the same substrate specificity

. S ee J.A. 7−8, 11; cf. Butamax (TM) Advanced Biofuels LLC v. Gevo, Inc ., 746 F. 3d 1302, 1306 (Fed. Cir. 2014) (acknowledging that assignment “of differ ent E [.] C [.] numbers to the same enzyme ” indicate s that “ the diffe rence between the nu m bers is the identity of the cofactor named ”)

, judgment vacated sub nom

. on other grounds Gevo, Inc. v. Butamax Advanced Biofuel s LLC , 135 S. Ct. 1173 (2015)

. T he PTAB had a reasonable basis to co nclude that because Senior disclose s the use of the FAD

GDH enzyme de scribed 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 inherent ly disclosed in Senior ’s enzyme preparation

. See J.A. 11; see also PAR Pharm

. , 773 F.3d at 1194

– 95 ( co ncluding that “[t]he claimed

. . . parameters . . . [were] inherent properties of the obvious . . . formulation ,” and thus “[t] he reduced food effect was an inherent result of [a composition] even if it was previously not known in the prior art that a food effect existed” ( internal quotation marks and citation omitted) ).

The PTAB properly adhered to our precedent regar ding the prima facie framework to conclude that Ikeda failed to present sufficient evidence to rebut the substa ntial evidence supporting that Senior’s FAD

- GDH enzyme preparation inherently disclos es the ’668 application’s claimed low maltose activity relative to glucose

. See In re Spada , 911 F.2d 705, 708 (Fed. Cir. 1990) (“[W] hen theIN RE : I KEDA F OOD RESEARCH CO ., LTD

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[US] PTO shows sound basis for believing that the pro ducts of the applicant and the prior art are the same, the applicant has the burden of s howing that they are not .” (emphasis added) (citation omitted) ). Ikeda did not pr esent evidence of test ing any of the enzyme preparations found in the prior art, such as by replicating Senior’s described process of creating its preparation, to support its argu ment that the purity of Senior’s preparation must have differed from the ’668 application because it co ntained maltose hydrolyzing contaminants (or impurities)

. See J.A. 11 0−25 (Reply Brief), J.A. 249− 447 (Reply to Final Action)

. Instead, Ikeda presented evidence in the form of U.S. Patent No. 7,655,130 (“Tsuji”) in support of its contention that because Tsuji’s purified FAD

- GDH E.C. 1.1.99.10 enzyme preparation “AOGDH” 6 has high maltose reactivity even after purification, there must likewi se be maltose

- hydrolyzing contaminant s in Senior’s FAD

- GDH preparation that would cause the preparation to exhibit more than 5% activity toward maltose relative to glucose

. See J.A. 110−25 (Ikeda Reply Brief); see also J.A. 432 (stating, in Tsuji’s Exampl e 1, that “[i] n the AOGDH purified prepara tion,

. . . 90% of maltose was already degraded into glucose, and after reacting for ten minutes, nearly 100% maltose was degraded ”). 7 The

6 Tsuji refers to its GDH enzyme preparation as “AOGDH” because it is recovered from native fungus Aspergillus oryzae. See J.A. 431.

7 The parties do not dispute that Tsuji, J.A. 426−48, which i ssued in 20 10 , qualifies as extrinsic evidence that may be relevant in determining what was inherently present in the prior art. See generally Appellant’s Br.; Appellee’s Br . Therefore, we deem it appropriate to consider Tsuji’s teachings here. See ASM Am., Inc. v. Genus, Inc.

, 401 F.3d 1340, 1347 (Fed. Cir. 2005) (conclu ding that extrinsic evidence that post

- dated the patent filing date nonetheless was helpful in determining how aIN RE : I KEDA F OOD RESEARCH CO ., LTD

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PTAB found that “Tsuji’s example of a contaminated preparation [did not] establish the presence of such co ntaminants in Senior.” J.A. 11. In addition , there is no specific evidence in Tsuji or of record that any contam inant in Tsuji results in a greater than 5% maltose activity relative to glucose. See Tsuji col. 1 l. 28−col. 14 l. 8

. To the contrary, Tsuji’s AOGDH preparation Table 1 shows low, i.e., “0.4%,” enzymatic reactivity to maltose relative to “100.0%” reactivity to glucose. Id . col. 12 ll. 1−43

. The PTAB could reasonably find that Tsuji does not persu asively rebut the prima facie finding of inherency. Moreover, simply because Senior never quantified maltose activity achieved by its disclosed embodiments does not preclude the PTAB’s evidentiary finding that Senior’s enzyme preparation process necessarily achieved th e low activity of 5% or less relative to glucose claimed in the Challenged Claims

, see J .A. 230 ; J.A. 11−12, especia lly since Senior’s enzyme’s stated E.C. classification was the same as the ’668 application’s enzyme, compare J.A. 293 with J.A. 843. “ In t he absence of any evidence that the claimed [ low activity ] would have been unexpected in light of [ Senior ’s] disclosure, there is no indication that the limitation is anything other than mere quantification of the results of a known process. ” Southwire

, 870 F.3d at 1311 . As our predecessor court explained, the fairness of shifting the burden “is evidenced by the [US] PTO’s inabi lity to manufacture products or to obtain and compare prior art products.” In re B est , 562 F.2d 1252, 1255 (CCPA 1997)

. Therefo re, we see no reason to call into question the PTAB’s finding “that the ‘ possible presence of contami nants’ in Senior’ s enzyme preparation [does not] render the claimed biosensor non -obvious.” J.A. 11;

see Elbit , 881 F.3d at 1537 (“If two inconsistent con cl u-

PHOSITA would have understood the claim term at the time it was filed).IN RE : I KEDA F OOD RESEARCH CO ., LTD

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sions may reasonably be drawn from the evidence in record, the PTAB’s decision to favor one conclusion over the other is the epitome of a decision that must be su stained upon review for substantial evidence.” (internal quotation marks and citation omitt ed) ). Ikeda’s evidence does not show that the PTAB lacked a reasonable basis for finding that Senior, as the operative prior art, nece ssarily possess es the ’668 application’s claimed low maltose activity relative to glucose

. See In re Spada , 911 F.2d at 709 (determining that an appellant “ showed no error, in science or in law

, in the [ PTAB ] ’s holding that

. . . the products [at issue] appeared to be the same and thus that [the appellant’s] products were not new”)

. Ikeda’s counterarguments lack merit. Fir st, Ikeda a rgues that the PTAB improperly “conflat[ed] Senior’s enzyme preparation with the enzyme per se ,” Appellant’s Br. 30, such that the E.C. 1.1.99.10 “designation does not mean that the enzyme preparation possesses only that single enzymat ic activit y, ” id

. at 32. However, Ikeda ’s logic misses the mark. The Challenged Claims do not require such exclusivity ; the only disputed limitation is that they require a low maltose relative to glucose

. See J.A

. 230. Thus, Ikeda’s contention that an E.C. design ation does not refer to a single enzymatic activity does not contradict the evidence supporting the PTAB’s finding that the E.C. 1.1.99.10 designation means that the prep aration has identical or similar substrate specificity for glu cose

. Second, Ikeda avers that the PTAB “ ignored [Ikeda]’s evidence when deciding whether there exists a reason able basis for inherency. ” Appellant’s Br. 36 (emphasis added)

. However , as we determine above, the PTAB expressly considered

, and found unpersua sive

, Ikeda’s evidence in support of its argument that the purity of Senior’s enzyme

prepara tion differed from the ’668 application and thus did not inherently possess low activity against maltose. See, e.g ., J.A. 11 ( stating that, “ [a] s an initial matter

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[Ikeda’s] speculation about the possibility that Sen ior’ s preparation may contain contaminants does not establish that Sen ior’ s preparation in fact had such contaminants

, ” and that while the PTAB “ agree[d] with [Ikeda] that the claims are directed to the activity of the enzyme layer and not just of GDH ,” it “d[id] not agree that the ‘ possible

presence of contaminants’ in Senior’s enzyme preparation renders the claimed biosensor non -obv ious” (emphases added) ), 12 (“[Ikeda’s] example relied on a different p reparation method than was used in Senior

. ”). Accordingly, the PTAB properly considered the record evidence in affirming the Examiner’s obviousness findings

. B

. Substantial Evidence Supports the PTAB ’s Finding that Objective Indicia of Nonobviousness D o Not Rebut the Prima Facie Case of Obviousness
The PTAB found, inter alia, that Ikeda’s “ objective i ndicia of nonobviousness ” do not “ demon strate[] the non

obviousness of the claimed biosensor” because the “scope of the [Challenged] Claims was not commensurate with the asserted need.” J.A. 15. The PTAB accorded Ikeda’s expert’s testimony little weight when he testified that

“ biosensors based on NAD

- GDH enzymes did not satisfy thi s long

- felt n eed because they require a cofactor” b ecause the Challenged Claims “encompass biosensors that use cofactors and thus do not satisfy the alleged need for dehydrogenase

- based glucose sensors that do not rely on a cofactor.” J.A. 15. Ikeda argues that “a ne ed existed since at least 1986 for improved blood glucose monitors” that

were “both specific and independent of separate cofa ctors.” Appellant’s Br. 43, 44 (capitalization modified). Ikeda also argues that the PTAB “erred by not crediting [Ikeda’s] evide nce of long

- felt need” for a GDH enzyme with no separate cofactor

. Id . at 47

. We disagree with Ikeda.

We see no error in the PTAB ’s analysis

, and ultimate rejection as unpersuasive

, of Ikeda’s evidence of secondaryIN RE : I KEDA F OOD RESEARCH CO ., LTD

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considerations relating to long

- felt ne ed. Ikeda ’s expert stated that twenty years elapsed after the publication of Senior, and seventeen years elapsed after a 1986 public ation by Ikeda’s expert document ing a “ need for a dehydr ogenase

- based glucose sensor” that “ha[d] no cofactor requirement,” before the ’668 application was filed

. J.A. 273−74 (expert declaration) ; see J.A. 1 4 (acknowled ging

, by the PTAB

, that “[a] lthough Senior does not require a cofactor, [Ikeda’s expert] contends that Sen ior’ s discl osure failed to satisfy the need for a deh ydrogenase- based glucose sensor because of the possible presence of conta minants and the low degree of purification” (internal quot ation marks and citation omitted) ). However, the PTAB considered Ikeda’s expert testimony and concluded that it did not have any substantive relevance

, see J.A. 14−15, a determination that we do not revisit, see Elbit , 881 F.3d at 1358 ( “The PTAB is entitled to weigh the credibility of the witnesses .” ( brackets and citation omitted)). Fu rther more , we recognize that c laim 22 employs the trans itional phra se “ comprising ” in the preamble

, J.A. 230, and

, therefore, does not exclude bio sensors that employ a cofac tor
, see CIAS, Inc. v. All. Gaming Corp. , 504 F.3d 1356, 1360 (Fed. Cir. 2007) (“In the patent claim context[,] the term ‘comprising’ is well understood to mean ‘inclu ding but not limited to.’ ” (citation omitted) )

. Thus, the Challenged C laims encompass biosensors that use cofa ctors
, and it follows that they do not satisfy Ikeda’s alleged need for dehydrogenase

- based glucose sensors that do not rely on a cofactor. 8

8 The PTAB found, as an alternative to its inherent obviousness analysis, that even if “Senior’s [FAD

- GDH] enzyme preparation includes contaminants, it would have been obvious for [a PHOSITA] to modify . . . Senior’s chromatographic purification to” achieve the claimed low

maltose activity of the ’668 application’s FAD

- GDH e n-IN RE : I KEDA F OOD RESEARCH CO ., LTD

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C ONCLUSION
We have considered Ikeda’s remaining arguments and find them unpersuasive. Accordingly, the Decision on Appeal of the U.S. Patent and Trademark Office’s Patent Trial and Appeal Board is

AFFIRMED

zyme. J.A. 12 (emphasis added) (internal quotation marks and citation omitted)

. Although Ikeda challenges this alternative finding on appeal

, s ee Appellant’s Br . 5, 39−41 , we need not address this alternative theory, given that we uphold the PTAB’s inherent obviousness dete rmination, see supra Section II.B; In re Gleave

, 560 F.3d 1331, 1338 (Fed. Cir. 2009) (declining to address altern ative grounds of unpatentability when we uphold one such ground).