Court Opinion

ID: 9403595
Source: CourtListenerOpinion
Date Created: 2023-06-21 15:03:12.065584+00
Date Added: 2024-06-11T17:20:08.242379
License: Public Domain

Case: 21-2356   Document: 56     Page: 1   Filed: 05/24/2023

   United States Court of Appeals
       for the Federal Circuit
                 ______________________

    MEDTRONIC, INC., MEDTRONIC VASCULAR,
                     INC.,
                  Appellants

                            v.

         TELEFLEX INNOVATIONS S.À.R.L.,
                     Appellee
              ______________________

   2021-2356, 2021-2358, 2021-2361, 2021-2363, 21-2365
                 ______________________

     Appeals from the United States Patent and Trademark
 Office, Patent Trial and Appeal Board in Nos. IPR2020-
 00126, IPR2020-00128, IPR2020-00132, IPR2020-00135,
 IPR2020-00137.
                  ______________________

                 Decided: May 24, 2023
                 ______________________

     TASHA JOY BAHAL, Wilmer Cutler Pickering Hale and
 Dorr LLP, Boston, MA, argued for appellants. Also repre-
 sented by MARK CHRISTOPHER FLEMING, HANNAH ELISE
 GELBORT, MADELEINE C. LAUPHEIMER; BRITTANY BLUEITT
 AMADI, JENNIFER L. GRABER, Washington, DC.

     J. DEREK VANDENBURGH, Carlson, Caspers, Vanden-
 burgh & Lindquist PA, Minneapolis, MN, argued for appel-
 lee. Also represented by PETER M. KOHLHEPP, TARA
 CATHERINE NORGARD, JOSEPH W. WINKELS.
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 2             MEDTRONIC, INC.   v. TELEFLEX INNOVATIONS S.À.R.L.

                     ______________________

     Before MOORE, Chief Judge, LOURIE and DYK, Circuit
                          Judges.
     Opinion for the court filed by Circuit Judge LOURIE.
          Dissenting opinion filed by Circuit Judge DYK.
 LOURIE, Circuit Judge.
      Medtronic, Inc. and Medtronic Vascular, Inc. (collec-
 tively, “Medtronic”) appeal from five final written decisions
 of the United States Patent and Trademark Office Patent
 Trial and Appeal Board (“the Board”) finding that Itou 1
 does not qualify as prior art to related U.S. Patents
 8,048,032, RE45,380, RE45,776, RE45,760, and RE47,379
 (collectively, “the challenged patents”) under pre-AIA first-
 to-invent provisions, and Medtronic had therefore not
 shown the challenged claims to be unpatentable. Med-
 tronic, Inc. v. Teleflex Innovations S.À.R.L., IPR2020-
 00126 (P.T.A.B. Jun. 7, 2021) (“Decision”), J.A. 1–75; Med-
 tronic, Inc. v. Teleflex Innovations S.À.R.L., IPR2020-
 00128 (P.T.A.B. Jun. 7, 2021), J.A. 76–150; Medtronic, Inc.
 v. Teleflex Innovations S.ÀR.L., IPR2020-00132 (P.T.A.B.
 Jun. 7, 2021), J.A. 151–222; Medtronic, Inc. v. Teleflex In-
 novations S.À.R.L., IPR2020-00135 (P.T.A.B. Jun. 7, 2021),
 J.A. 223–98; Medtronic, Inc. v. Teleflex Innovations
 S.À.R.L., IPR2020-00137 (P.T.A.B. Jun. 7, 2021), J.A. 299–
 373. 2 For the reasons provided below, we affirm.

      1   U.S. Patent 7,736,355 to Itou et al. (“Itou”).
      2   The five final written decisions in the IPRs consol-
 idated on appeal share similar sections on conception and
 reduction to practice. The decision in Medtronic, Inc. v. Te-
 leflex Innovations S.À.R.L., IPR2020-00126 (P.T.A.B. Jun.
 7, 2021), J.A. 1–75, is representative and cited throughout
 as such.
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 MEDTRONIC, INC.   v. TELEFLEX INNOVATIONS S.À.R.L.           3

                         BACKGROUND
      The challenged patents, developed by Vascular Solu-
 tions Inc. (“VSI”) but now owned by appellee Teleflex Inno-
 vations S.À.R.L. (“Teleflex”), all descend from a common
 application filed on May 3, 2006 and share a common spec-
 ification. The challenged patents are directed to guide ex-
 tension catheters that use a tapered inner catheter that
 runs over a standard coronary guidewire to reduce the like-
 lihood that a guide catheter will dislodge from the coronary
 artery’s opening (i.e., ostium). See, e.g., ’032 patent, col. 1
 ll. 32–36, col. 2 ll. 53–59.
     According to Teleflex, VSI conceived the claimed inven-
 tion in early 2005 and then worked to develop it under the
 “GuideLiner” name. Teleflex asserts that what was known
 as the “rapid exchange” or “RX” version of the GuideLiner
 practices the challenged patents. Decision, J.A. 17. How-
 ever, in the same time period, VSI also worked on develop-
 ing an “over-the-wire” or “OTW” version of the GuideLiner,
 which was more akin to the prior art guide extension cath-
 eters and does not practice the challenged patents. Id. at
 J.A. 19. Because the over-the-wire GuideLiner was more
 similar to devices already in existence, it had fewer chal-
 lenges to overcome and work on it progressed more rapidly
 than for the rapid exchange device. Id. at J.A. 36. The
 rapid exchange GuideLiner eventually entered the market
 in 2009. Id. at J.A. 61.
     Medtronic filed thirteen petitions for inter partes re-
 view (“IPR”) of the challenged patents, eleven of which
 were instituted and five of which are consolidated in this
 appeal. These five IPR petitions asserted Itou as the pri-
 mary prior art reference under pre-AIA 35 U.S.C. § 102(e)
 (2012). Following institution, Teleflex filed a consolidated
 response addressing conception and reduction to practice,
 asserting that Itou did not qualify as prior art because the
 claimed inventions were (1) conceived prior to Itou’s filing
 date of September 23, 2005 (i.e., the critical date), and (2)
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 4           MEDTRONIC, INC.   v. TELEFLEX INNOVATIONS S.À.R.L.

 were (a) actually reduced to practice before the critical date
 or (b) diligently pursued until their constructive reduction
 to practice through their effective filing in May 2006. In
 support of its contentions, Teleflex submitted numerous
 declarations, including from inventors and noninventors,
 as well as nearly 75 documentary exhibits including inven-
 tor lab notebooks, internal company memoranda and
 presentations, invoices and sales orders, photographs, en-
 gineering drawings, and documents from outside patent
 counsel. Decision, J.A. 13.
     The Board found that the evidence demonstrated that
 the claimed inventions were (1) conceived no later than Au-
 gust 2005, i.e., before the critical date, and (2) either (a)
 actually reduced to practice for their intended purpose in
 April and July 2005, prior to the critical date, or (b) dili-
 gently worked on toward constructive reduction to practice
 on May 3, 2006, the challenged patents’ effective filing
 date. Id. at J.A. 34, 61–62, 71. In so doing, the Board found
 that the intended purpose of the claimed inventions was
 providing improved backup support for the guide catheter,
 rejecting Medtronic’s suggestion that the intended pur-
 pose, or additional intended purpose, was providing backup
 support necessary for accessing and crossing tough or
 chronic occlusions. Id. at J.A. 53. The Board therefore de-
 termined that Itou did not qualify as prior art to the chal-
 lenged patents under pre-AIA 35 U.S.C. § 102(e), thereby
 eliminating the challenges presented in the five IPRs rele-
 vant to this appeal. The Board thus concluded that Med-
 tronic had failed to demonstrate that the challenged claims
 were unpatentable.
    Medtronic appealed.        We have jurisdiction under
 28 U.S.C. § 1295(a)(4)(A).
                         DISCUSSION
     In considering whether or not a reference qualifies as
 prior art under pre-AIA 35 U.S.C. § 102(e), we must con-
 sider whether or not “the invention was described in . . . a
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 MEDTRONIC, INC.   v. TELEFLEX INNOVATIONS S.À.R.L.           5

 patent granted on an application for patent by another filed
 in the United States before the invention by the applicant
 for patent.” A patent owner may antedate an asserted
 prior art patent by showing conception of the claimed in-
 vention prior to the critical date and either actual reduc-
 tion to practice prior to the critical date or “reasonably
 continuous diligence” in reducing the invention to practice
 until its effective filing date. See ATI Techs. v. Iancu, 920
 F.3d 1362, 1369 (Fed. Cir. 2019); Tyco Healthcare Grp. v.
 Ethicon Endo-Surgery, Inc., 774 F.3d 968, 975 (Fed. Cir.
 2014). Inventor declarations submitted to antedate a ref-
 erence must be corroborated, and corroboration is governed
 by a “rule of reason” standard. Perfect Surgical Techs., Inc.
 v. Olympus Am., Inc., 841 F.3d 1004, 1007–09 (Fed. Cir.
 2016).
     In an IPR, the petitioner bears the ultimate burden of
 persuasion on invalidity, which never shifts to the patent
 owner. Dynamic Drinkware, LLC v. Nat’l Graphics, Inc.,
 800 F.3d 1375, 1378 (Fed. Cir. 2015). However, when a pa-
 tent owner attempts to antedate an asserted prior art ref-
 erence, the patent owner takes on a temporary burden of
 production. Id. at 1378–79. Once that burden is met, the
 burden shifts back to the petitioner. Id. at 1379.
     We review the Board’s factual findings on reduction to
 practice and diligence for substantial evidence, and its le-
 gal conclusion of priority de novo. E.I. du Pont de Nemours
 & Co. v. Unifrax I LLC, 921 F.3d 1060, 1075 (Fed. Cir.
 2019). Medtronic does not challenge the Board’s findings
 of conception prior to the critical date on appeal, but chal-
 lenges both the Board’s findings on actual reduction to
 practice and reasonable diligence toward constructive re-
 duction to practice. We address each argument in turn.
                                I
      To establish actual reduction to practice before the crit-
 ical date, it must have been shown that “(1) [the inventors]
 constructed an embodiment or performed a process that
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 6           MEDTRONIC, INC.   v. TELEFLEX INNOVATIONS S.À.R.L.

 met all the limitations of the [claimed invention]; and (2)
 [the inventors] determined that the invention would work
 for its intended purpose.” Cooper v. Goldfarb, 154 F.3d
 1321, 1327 (Fed. Cir. 1998). Medtronic challenges the
 Board’s determinations regarding both of these elements
 on three grounds. First, Medtronic argues that the Board
 erred in identifying the intended purpose of the claimed in-
 ventions. Second, Medtronic argues that, even if the
 Board’s finding of the intended purpose was correct, the
 Board erred in not requiring comparative testing to demon-
 strate that the invention worked for that purpose. Third,
 Medtronic argues that the Board erred in relying solely on
 uncorroborated inventor testimony as evidence of actual
 reduction to practice. We disagree for the reasons provided
 below.
                               A
      Medtronic argues that the intended purpose should be
 both, as the Board found, providing increased backup sup-
 port as compared with a guide catheter alone and facilitat-
 ing the delivery of interventional devices through tough or
 chronic occlusions. Medtronic faults the Board for relying
 on extrinsic evidence to determine the intended purpose
 when the patents’ specifications and claims are the proper
 source of information. Medtronic further argues that had
 the Board correctly determined the intended purpose, it
 could not have found that Teleflex proved that the proto-
 types functioned for that purpose. Teleflex argues that
 Medtronic waived the argument that the Board erred by
 considering extrinsic evidence in determining the intended
 purpose when it repeatedly urged the Board to consider ex-
 trinsic evidence and failed to point the Board to any intrin-
 sic evidence, and the Board’s determination of the intended
 purpose is correct.
    Similar to claim construction, a determination of an in-
 vention’s intended purposes is a legal issue, reviewed de
 novo. See z4 Techs., Inc. v. Microsoft Corp., 507 F.3d 1340,
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 MEDTRONIC, INC.   v. TELEFLEX INNOVATIONS S.À.R.L.            7

 1352 (Fed. Cir. 2007) (affording no deference to district
 court’s reading of patents’ language to “define[] the ‘in-
 tended purpose’ of the invention”). Because we evaluate
 the intended purpose without deference to the Board’s de-
 termination, it is of no consequence whether the Board re-
 lied on extrinsic evidence or whether Medtronic waived the
 argument that doing so would have been in error. Regard-
 less, although the patents themselves are the most im-
 portant and, indeed, most persuasive evidence of the
 patents’ intended purpose, we find it is appropriate to con-
 sider extrinsic evidence, particularly when it does not con-
 tradict the patents themselves. Medtronic cites no case
 showing otherwise.
      We, like the Board, find Medtronic’s proposed intended
 purpose to be overly narrow. See Decision, J.A. 52–53. Alt-
 hough the challenged patents do mention crossing “tough”
 or “chronic” occlusions, we find that to be a specific example
 within a broader general purpose. Indeed, as the Board
 found, the challenged patent specification itself recognizes
 a broader purpose when discussing the field and back-
 ground of the invention. See, e.g., ’032 patent at col. 1 ll. 8–
 11 (“More particularly the present invention relates to
 methods and apparatus for increasing backup support for
 catheters inserted into the coronary arteries from the
 aorta.”), col. 2 ll. 45–49 (“Thus, the interventional cardiol-
 ogy art would benefit from the availability of a system that
 would be deliverable through standard guide catheters for
 providing backup support by providing the ability to effec-
 tively create deep seating in the ostium of the coronary ar-
 tery.”). Although that intrinsic evidence is sufficient, a
 broader purpose than that urged by Medtronic is further
 supported by both expert and inventor testimony. See De-
 cision, J.A. 54–55 (citing J.A. 12012; J.A. 11815–16; J.A.
 11834).
    Moreover, the evidence suggests a broader intended
 purpose than the Board found may even be appropriate.
 The challenged patents are titled “Coaxial Guide Catheter
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 8           MEDTRONIC, INC.   v. TELEFLEX INNOVATIONS S.À.R.L.

 for Interventional Cardiology Procedures,” and the claims
 are generally directed to a “device for use with a standard
 guide catheter.” See, e.g., ’032 patent at Title, col. 10 ll. 21;
 see also J.A. 11816 (inventor describing the intended pur-
 pose). The claims do not mandate a purpose beyond per-
 forming the functions of a guide extension catheter. This
 is not an obviousness inquiry. The very title of the patents
 themselves, “Coaxial Guide Catheter for Interventional
 Cardiology Procedures,” describes the purpose of the
 claimed inventions, and it is undisputed that the claim lan-
 guage does not impose a further purpose than this. We
 therefore reject Medtronic’s argument that the intended
 purpose of the claimed invention should be narrower than
 that determined by the Board.
                                B
      Medtronic further argues that, even assuming the
 Board’s determined intended purpose is correct, there is no
 evidence that Teleflex’s claimed device compared favorably
 with a guide catheter alone (i.e., worked for the Board’s de-
 termined intended purpose of “providing improved backup
 support for a guide catheter”). Decision, J.A. 53 (emphasis
 added). Teleflex argues that Medtronic forfeited the argu-
 ment that comparative testing was required by not raising
 it before the Board, and, regardless, testing is not required
 to confirm aspects of the invention that would have already
 been known to a person of ordinary skill in the art.
     As an initial matter, we do not find Medtronic’s argu-
 ment on this point to be forfeited. Generally, a federal ap-
 pellate court does not consider issues not raised before the
 lower tribunal. Singleton v. Wulff, 428 U.S. 106, 120
 (1976). The exact phrasing of the argument need not have
 been used below “so long as it can be said that the tribunal
 was ‘fairly put on notice as to the substance of the issue.’”
 Nike Inc. v. Adidas AG, 812 F.3d 1326, 1342 (Fed. Cir.
 2016) (citing Consolidation Coal Co. v. United States, 351
 F.3d 1374, 1378 (Fed. Cir. 2003) (quoting Nelson v. Adams,
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 529 U.S. 460, 469 (2000) (“But [issue preservation] does not
 demand the incantation of particular words; rather, it re-
 quires that the lower court be fairly put on notice as to the
 substance of the issue.”))). But even if an issue was not
 presented below, there is no absolute bar to considering
 and deciding the issue on appeal, as forfeiture is a matter
 of discretion. Harris Corp. v. Ericsson Inc., 417 F.3d 1241,
 1251 (Fed. Cir. 2005) (“An appellate court retains case-by-
 case discretion over whether to apply waiver.”).
     Here, Medtronic argued in their Reply that “Teleflex
 cannot prove VSI performed any testing, much less testing
 to confirm intended purpose.” J.A. 24495; see also J.A.
 25042 (“The Board cannot evaluate whether Teleflex’s test-
 ing ‘evidence’ proves that VSI demonstrated that [the in-
 vention] would work for its intended purpose.”). We
 consider these assertions sufficient to preserve Medtronic’s
 argument that comparative testing was required given the
 intended purpose determined by the Board. Although
 Medtronic’s statements before the Board more generally
 addressed the insufficiency of the evidence and corrobora-
 tion of testing, without a specific mention to “comparative”
 testing, they still address the same, general issue: whether
 or not the testing showed the invention worked for its in-
 tended purpose.
      Regardless, we find the testing performed to be suffi-
 cient to show that the claimed invention worked for its in-
 tended purpose as determined by the Board. Sufficiency of
 the testing required to show an invention worked for its
 intended purpose is a question of fact reviewed for substan-
 tial evidence. See z4 Techs., 507 F.3d at 1352 (“[T]he ne-
 cessity and sufficiency of such testing are factual issues.”);
 Scott v. Finney, 34 F.3d 1058, 1061–62 (Fed. Cir. 1994)
 (“[T]he testing requirement depends on the particular facts
 of each case.”). Here, the Board thoroughly reviewed and
 analyzed the evidence of testing in the record, and we de-
 cline to remake or reweigh its factual findings.
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      Namely, we find the Board’s conclusion that the
 claimed invention was determined to work for its intended
 purpose was supported by substantial evidence. As the
 Board noted, both inventors Howard Root and Gregg Sut-
 ton testified regarding testing performed on a prototype of
 the claimed invention. Decision, J.A. 44 (citing J.A. 11815,
 11834, 11971, 11982–83). Although these tests did not spe-
 cifically compare the invention prototype with a guide cath-
 eter alone, they enabled the inventors to observe the forces
 exerted on the prototype and the durability of the proto-
 type. Id. The Board determined that these tests, although
 “more qualitative than quantitative,” were sufficient to en-
 able the inventors to confirm that the prototype would
 work for its intended purpose—providing increased backup
 support as compared with a guide catheter alone. Id. We
 agree. The Board’s determined intended purpose did not
 mandate a 1:1 comparison or quantitative assessment to
 show an “increase” or “improvement” in function. Rather,
 it simply requires that an inventor, a skilled artisan, would
 observe the tests and understand that they indicate the
 prototype is more effective than a guide catheter alone.
 And that is the case here. See, e.g., J.A. 12010–12 (expert
 testimony that “actual reduction to practice of the Guide-
 Liner invention would have required little if any testing,”
 and that, to the extent it did, “qualitative testing would
 have been sufficient”).
      Because we find the Board’s finding of actual reduction
 to practice under its determined intended purpose sup-
 ported by substantial evidence, we find the same would be
 true for our suggested, broader, intended purpose of simply
 functioning as a guide extension catheter. Indeed, as coun-
 sel for Appellant conceded at oral argument, “[w]e may not
 need comparative testing if the Board had found a different
 intended purpose.” Oral Arg. at 3:18–22.
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 MEDTRONIC, INC.   v. TELEFLEX INNOVATIONS S.À.R.L.        11

                               C
     Finally, Medtronic argues that Teleflex’s evidence of
 actual reduction to practice is insufficiently corroborated.
 Inventor testimony may serve as evidence of reduction to
 practice, but it must be corroborated by independent evi-
 dence. Cooper, 154 F.3d at 1330. The sufficiency of such
 corroborating evidence is evaluated under a “rule of rea-
 son,” considering all pertinent evidence. Id. Corroboration
 can come from documentary evidence, noninventor testi-
 mony, or a combination of both. Loral Fairchild Corp. v.
 Matsushita Elec. Indus. Co., 266 F.3d 1358, 1364 (Fed. Cir.
 2001) (“Under the ‘rule of reason,’ the inventor's testimony
 must be sufficiently corroborated by independent evidence,
 but not necessarily documentary evidence.”). Corroborat-
 ing evidence may also be circumstantial. Cooper, 154 F.3d
 at 1330 (“In order to corroborate a reduction to practice, it
 is not necessary to produce an actual over-the-shoulder ob-
 server. Rather, sufficient circumstantial evidence of an in-
 dependent nature can satisfy the corroboration
 requirement.”). Nor must every individual aspect of reduc-
 tion to practice be corroborated. E.I. du Pont, 921 F.3d at
 1077. Rather, the corroborative evidence simply needs to
 be sufficient to support the credibility of the inventors’
 story. Id.
     Here, we find the inventors’ testimony of actual reduc-
 tion to practice, including that the invention worked for its
 intended purpose, sufficiently corroborated. Inventors
 Root and Sutton testified regarding the building and test-
 ing of a prototype of the claimed invention. J.A. 11815,
 11834, 11971, 11982–83. As the Board found, that testi-
 mony was supported by both documentary evidence and
 noninventor testimony. Decision, J.A. 36–51. For example,
 Steven Erb, a former Research & Development Technician
 at VSI, testified that he “worked on the early GuideLiner
 prototypes,” including the “first rapid exchange Guide-
 Liner prototypes in early 2005.” J.A. 12000. He confirmed
 that “[t]hese prototypes were then tested, including for
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 12          MEDTRONIC, INC.   v. TELEFLEX INNOVATIONS S.À.R.L.

 durability . . . and for functionality,” which informed them
 that “it would work.” J.A. 12001–02. Erb testified that he
 was both personally involved in some of the testing, and
 recalls watching the inventors perform testing on the pro-
 totypes on multiple occasions. Id. Deborah Schmalz, the
 former Vice President of Regulatory and Clinical Affairs at
 VSI, testified that she “specifically recall[ed] that a work-
 ing prototype of the rapid exchange version of GuideLiner
 was created” prior to August 24, 2005. J.A. 9878–79.
      Those findings are further supported by documentary
 evidence. For example, reports and invoices show that VSI
 ordered specialized “hypotubes” for prototypes of the rapid
 exchange GuideLiner in the first half of 2005. See, e.g., De-
 cision, J.A. 37–51; J.A. 9592–97 (project spend report); J.A.
 11468 (invoice and purchase orders); J.A. 11471 (invoice
 and purchase orders). As the Board found, the dimensions
 of that hypotubing are consistent with the dimensions pro-
 vided in the patents themselves and engineering drawings
 specific to the rapid exchange GuideLiner. See, e.g., Deci-
 sion, 38–51; ’032 patent at col. 3 ll. 30–32, 43–46, 55–59,
 col. 7 ll. 19–25; J.A. 11592–93, 11595 (engineering draw-
 ings). Even Medtronic’s expert witness acknowledged that
 it “doesn’t make a lot of sense” for VSI not to have assem-
 bled the purchased parts together once they were ordered
 and received. J.A. 13920 at 208:10–25. And Medtronic con-
 cedes that a benchtop model depicted in a July 2005 sales
 presentation could have been used to test a device like the
 rapid exchange GuideLiner. See J.A. 9725 (photograph);
 Decision, J.A. 58 (citing Medtronic, Inc. v. Teleflex Innova-
 tions S.À.R.L., IPR2020-00126, Conception and Reduction
 to Practice Reply at 17–18); see also J.A. 12011–12 (expert
 testimony regarding bench model testing). That evidence,
 taken together, is, at minimum, circumstantial evidence of
 corroboration.
    Medtronic’s main complaint is that some of the evi-
 dence in the record of corroboration is unclear as to
 whether or not it relates to the over-the-wire GuideLiner
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 MEDTRONIC, INC.   v. TELEFLEX INNOVATIONS S.À.R.L.         13

 or the rapid exchange GuideLiner. That is true, and cer-
 tain documents could only be connected to the rapid ex-
 change prototype through inventor testimony, which
 carries little to no weight in the context of corroboration;
 one cannot corroborate oneself, after all. However, when
 viewing the pertinent evidence in its entirety, we still find
 the inventors’ story corroborated. Erb’s and Schmalz’ tes-
 timony, along with that of others and numerous docu-
 ments, specifically mention the rapid exchange GuideLiner
 or can be connected to that version of the device in ways
 independent of the inventors’ testimony.
      For example, Teleflex asserts that a Computer Aided
 Design schematic from August 2005, J.A. 9751–52, corrob-
 orates the inventors’ testimony that they had moved be-
 yond prototyping and testing at that point in time.
 Medtronic challenges the Board’s reliance on inventor
 Root’s testimony to connect that document to the reduction
 to practice of the rapid exchange prototype. Although
 Root’s testimony certainly enunciates that connection, his
 testimony is not required to establish the document’s cor-
 roborative value. The document is labeled “GuideLiner
 Rapid Exchange/Preliminary Design Assumptions/Rev
 X03,” indicating that the drawing is indisputably linked to
 the rapid exchange prototype, not the over-the-wire proto-
 type, and that it is not the first, or even second, version of
 that drawing. See Decision, J.A. 42–43. The part number
 (20-0658) on the drawing is also consistent with those iden-
 tified in certain purchase documents for tubing. Compare
 J.A. 9751–52 with J.A. 9749–50, J.A. 11480–84, and J.A.
 11466–71. Moreover, the “law does not impose an impossi-
 ble standard of ‘independence’ on corroborative evidence by
 requiring that every point of a reduction to practice be cor-
 roborated by evidence having a source totally independent
 of the inventor; indeed, such a standard is the antithesis of
 the rule of reason.” Knorr v. Pearson, 671 F.2d 1368, 1374
 (CCPA 1982). We find the inventors’ testimony regarding
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 14          MEDTRONIC, INC.   v. TELEFLEX INNOVATIONS S.À.R.L.

 reduction to practice sufficiently corroborated under the
 rule of reason standard.
     Because we find the Board’s determination of actual re-
 duction prior to the critical date supported by substantial
 evidence, we affirm the Board’s finding that Itou does not
 qualify as prior art to the challenged patents under
 35 U.S.C. § 102(e). Because Itou does not qualify as prior
 art, we likewise affirm the Board’s holding that Medtronic
 did not demonstrate by a preponderance of the evidence
 that the challenged claims of the challenged patents are
 unpatentable.
                               II
      Medtronic additionally argues that the Board erred in
 finding that there was reasonably continuous diligence in
 reducing the invention to practice during the critical pe-
 riod. Because we agree with the Board that the claimed in-
 vention was actually reduced to practice prior to the critical
 date and affirm the Board’s finding that Itou did not qual-
 ify as prior art on that basis, there is no need to reach the
 issue of whether or not reasonable diligence was exercised.
                         CONCLUSION
     We have considered Medtronic’s remaining arguments
 but find them unpersuasive. For the foregoing reasons, the
 decision of the Board is affirmed.
                         AFFIRMED
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    United States Court of Appeals
        for the Federal Circuit
                   ______________________

    MEDTRONIC, INC., MEDTRONIC VASCULAR,
                     INC.,
                  Appellants

                              v.

          TELEFLEX INNOVATIONS S.À.R.L.,
                      Appellee
               ______________________

  2021-2356, 2021-2358, 2021-2361, 2021-2363, 2021-2365
                 ______________________

     Appeals from the United States Patent and Trademark
 Office, Patent Trial and Appeal Board in Nos. IPR2020-
 00126, IPR2020-00128, IPR2020-00132, IPR2020-00135,
 IPR2020-00137.
                  ______________________

 DYK, Circuit Judge, dissenting.
     Contrary to the majority, I think that Itou 1 has been
 shown to be prior art to the patents at issue 2 and therefore
 could support a determination of anticipation or obvious-
 ness. This is so because, under the pre-America Invents

     1    U.S. Patent No. 7,736,355 to Itou et al. (“Itou”).
     2    The challenged patents claim priority to the appli-
 cation that led to U.S. Patent No. 8,048,032 (“’032 patent”),
 filed on May 3, 2006.
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 2           MEDTRONIC, INC.   v. TELEFLEX INNOVATIONS S.À.R.L.

 Act (“AIA”) 35 U.S.C. § 102(e), applicable to this case, 3 Itou
 has an earlier filing date than that of the ’032 patent, and
 the evidence in this case fails to adequately corroborate in-
 ventor testimony that the rapid exchange (“RX”) Guide-
 Liner invention had been reduced to practice before Itou’s
 filing date of September 23, 2005. I agree with the majority
 that the Board correctly identified the object of the inven-
 tion as “providing increased backup support,” 4 Panel Op. 6,
 and that the testimony and corroborating evidence support
 the Board’s finding that prototypes reflecting the invention
 were assembled before the priority date. Panel Op. 12. My
 disagreement lies with respect to the issue of testing. Spe-
 cifically, the evidence does not corroborate that testing of
 the RX GuideLiner prototypes before the critical date had
 shown them to work for their intended purpose.
                                I
    “To show reduction to practice, [a patent owner] must
 demonstrate that the invention is ‘suitable for its intended

     3    The AIA’s first-to-file provisions do not apply to the
 challenged patents, because they apply to patents with an
 effective filing date on or after March 16, 2013. See AIA,
 Pub. L. No. 112-29, § 3(n)(1), 125 Stat. 284, 293 (2011).
     4    The majority confusingly suggests the intended
 purpose of the invention may be even broader than the pur-
 pose identified by the Board and urged by Teleflex. Panel
 Op. 7–8; see also J.A. 52 (noting that Teleflex’s position was
 that the intended purpose of the invention was “to increase
 backup support” (citation omitted)). I do not understand
 the majority to rest its disposition on a purpose broader
 than that found by the Board. And reviewing the Board’s
 decision using a different standard than the Board’s own
 standard would present a problem under Securities & Ex-
 change Commission v. Chenery Corp., 332 U.S. 194, 196
 (1947).
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 MEDTRONIC, INC.   v. TELEFLEX INNOVATIONS S.À.R.L.         3

 purpose.’” Scott v. Finney, 34 F.3d 1058, 1061 (Fed. Cir.
 1994) (quoting Steinberg v. Seitz, 517 F.2d 1359, 1363
 (C.C.P.A. 1975)). This case does not involve a situation
 where the invention is “so simple and [its] purpose and ef-
 ficacy so obvious that [its] complete construction is suffi-
 cient to demonstrate workability.” Id. (citation omitted).
 Under such circumstances, testing is required to establish
 a reduction to practice. Id. at 1063 (citation omitted). As
 both the majority and the Board assumed, testing was re-
 quired to establish a reduction to practice here. See Panel
 Op. 9–10; J.A. 57 n.22. “The issue . . . is not whether it
 might be possible to reduce the invention to practice by la-
 boratory testing, but whether the particular tests made by
 [the inventor] were sufficient for that purpose.” Elmore v.
 Schmitt, 278 F.2d 510, 513 (C.C.P.A. 1960). The evidence
 must show that the “tests accurately reproduced the oper-
 ating conditions which would be encountered in any prac-
 tical use of the invention.” Id.
                               II
      The testimony of the inventors here never describes
 (1) any specific tests showing the RX GuideLiner proto-
 types would work for their intended purpose of providing
 increased backup support 5 or (2) the results of the tests

     5   The inventors do describe in general terms tests re-
 garding the simple delivery of cardiology devices in bench-
 top cardiac models, and they mention “pull tests to assess
 the durability of the prototype[s].” J.A. 11816 (Root Decl.
 ¶ 18); see also J.A. 11982 (Sutton Decl. ¶ 41). The Board
 also described the “bench-top coronary models, including
 two-dimensional (“2D”) acrylic heart models and three-di-
 mensional (“3D”) glass heart models, to simulate the native
 anatomy and environment,” in which these tests were per-
 formed. J.A. 43. On their face, these tests do not relate to
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 4           MEDTRONIC, INC.   v. TELEFLEX INNOVATIONS S.À.R.L.

 they did conduct. One inventor characterized the tests as
 “more qualitative than quantitative,” J.A. 11983 (Sutton
 Decl. ¶ 41), and both declarant inventors relied in large
 part on their own assessment that they knew that the pro-
 totypes would work. See, e.g., J.A. 11834 (Root Decl. ¶ 47)
 (testifying that, before performing any tests, the inventor
 “already had confidence that the rapid exchange Guide-
 Liner would work for its intended purpose”).
                               III
     Even if the inventors’ testimonies were sufficient to
 show relevant testing, “[i]n order to establish an actual re-
 duction to practice, an inventor’s testimony must be corrob-
 orated by independent evidence.” Cooper v. Goldfarb, 154
 F.3d 1321, 1330 (Fed. Cir. 1998). As with all “inventive
 facts,” an “inventor’s testimonial assertions” regarding
 testing “require corroboration by independent evidence.”
 Brown v. Barbacid, 276 F.3d 1327, 1335 (Fed. Cir. 2002).
     With respect to testing, the Board barely addressed the
 issue of corroboration. At best, it relied on two items. First,
 the Board referenced a July 2005 sales presentation that
 includes a picture of an over-the-wire (“OTW”) GuideLiner
 device inserted into a benchtop cardiac model. See J.A. 43;
 J.A. 58. Second, the Board may have relied on the testi-
 mony of two non-inventor witnesses, Steven Erb (a techni-
 cian and machinist at Vascular Solutions), see J.A. 58, and
 Deborah Schmalz (former Vice President of Regulatory and

 whether the prototypes provided increased backup sup-
 port. On that question, the inventors testified that they
 “observed the forces involved in navigating the GuideLiner
 prototype through such a [benchtop coronary] model,”
 J.A. 11816 (Root Decl. ¶ 18); see also J.A. 11983 (Sutton
 Decl. ¶ 41), but they did not provide any explanation of
 what the testing found and how any results indicated that
 the devices provided increased backup support.
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 MEDTRONIC, INC.   v. TELEFLEX INNOVATIONS S.À.R.L.         5

 Clinical Affairs at Vascular Solutions). See J.A. 45. Nei-
 ther the 2005 sales presentation nor the non-inventor tes-
 timony is adequate corroboration.
     As to the first—the 2005 sales presentation—even if
 the single picture of an OTW GuideLiner device could lend
 some support for testing of that OTW GuideLiner device, it
 shows nothing about testing the RX GuideLiner proto-
 types, the devices at issue here. The OTW device is quite
 different: As the majority agrees, the OTW GuideLiner
 “was more akin to the prior art guide extension catheters
 and does not practice the challenged patents,” and, as a re-
 sult, “it had fewer challenges to overcome and work on it
 progressed more rapidly than for the rapid exchange de-
 vice.” Panel Op. 3. Evidence that does not even correspond
 to an embodiment of the patented invention cannot corrob-
 orate that invention’s reduction to practice. See In re NPT,
 Inc., 654 F.3d 1279, 1292 (Fed. Cir. 2011).
     As to the second, the non-inventor testimony also does
 not offer adequate corroboration. The Board relied on Erb’s
 testimony that he “worked on the early GuideLiner proto-
 types,” including the “first rapid exchange GuideLiner pro-
 totypes in early 2005,” related to prototypes allegedly made
 in January or February 2005. J.A. 12000 (Erb Decl. ¶ 8);
 J.A. 37. But the inventor testimony of reduction to practice
 is based on later prototypes, the so-called April and July
 prototypes. See J.A. 11834 (Root Decl. ¶ 48). The early
 2005 prototypes Erb worked on are not claimed to have re-
 duced the invention to practice. See J.A. 36 n.17. Accord-
 ingly, Erb’s testimony about his work on these early
 prototypes has no corroborative value for the question of
 whether the April and July prototypes were ever tested and
 shown to work for their intended purpose, let alone that
 these later prototypes were tested and shown to work by
 the critical date.
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 6           MEDTRONIC, INC.   v. TELEFLEX INNOVATIONS S.À.R.L.

     As for the April and July prototypes, all Erb testified is
 that “[a]dditional testing . . . was performed on these sub-
 sequent prototypes” and that “[he] recall[ed] watching [in-
 ventor] Howard Root and others working in R&D test these
 subsequent prototypes, as well.” J.A. 12002 (Erb Decl.
 ¶ 12). There is no specific description of what tests were
 performed or the results of the tests. Most significantly,
 there is no specific testimony of when the tests were per-
 formed and whether they were performed before the criti-
 cal date.
     The Board also mentioned Schmalz’s testimony that
 she “specifically recall[ed] that a working prototype of the
 rapid exchange version of GuideLiner was created” before
 August 24, 2005.” See J.A. 45 (quoting J.A. 9879 (Schmalz
 Decl. ¶ 7)). The fact a working prototype was created does
 not corroborate the inventors’ testimony of testing.
 Schmalz did not testify to witnessing any tests, much less
 testify regarding what tests were performed, when they
 were performed, or the results of the tests. We have held
 that, absent other corroborating evidence, “vague testi-
 mony” like this by non-inventors is insufficient to corrobo-
 rate    inventor’s    testimony     that   an   experiment
 demonstrated an invention had been reduced to practice.
 Brown, 276 F.3d at 1337.
     The majority relies on additional items for corrobora-
 tion not relied on by the Board to corroborate testing. The
 majority relies on documents related to the purchasing of
 parts. See Panel Op. 12 (citing J.A. 9592–97; J.A. 11468;
 J.A. 11471). This may corroborate assembly of prototypes
 but hardly corroborates testing, let alone successful testing
 by the critical date.
     The majority also relies on an August 2005 Computer
 Aided Design (“CAD”) schematic of an RX GuideLiner de-
 vice. See Panel Op. 13 (citing J.A. 9751–52). While this
 CAD schematic may corroborate the inventors’ testimony
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 MEDTRONIC, INC.   v. TELEFLEX INNOVATIONS S.À.R.L.         7

 that they had conceived of the RX GuideLiner invention be-
 fore the critical date—which is not in dispute—it says noth-
 ing about testing of an RX GuideLiner device. The only
 testimony connecting the CAD schematic to the question of
 testing of the RX GuideLiner is the conclusory testimony of
 the inventors. See J.A. 11835 (Root Decl. ¶ 49) (the sche-
 matic “reflects the fact that we had moved past the proto-
 typing phase and were getting ready to begin the formal
 quality process for bringing a completed medical device to
 market”); J.A. 11981 (Sutton Decl. ¶ 39). The majority
 agrees that the testimony of the inventors “carries little to
 no weight in the context of corroboration.” Panel Op. 12–
 13; see also Apator Miitors ApS v. Kamstrup A/S, 887 F.3d
 1293, 1296 (Fed. Cir. 2018).
                               IV
      The majority suggests that finding the evidence insuf-
 ficient here would impose an “impossible standard of ‘inde-
 pendence’ on corroborative evidence by requiring that
 every point of reduction to practice be corroborated by evi-
 dence having a source totally independent of the inventor.”
 Panel Op. 13 (quoting Knorr v. Pearson, 671 F.2d 1368,
 1374 (C.C.P.A. 1982)). That is hardly the case. Teleflex
 produced essentially no internal documents corroborating
 any testing that Vascular Solutions was doing with the RX
 GuideLiner prototypes in the critical period in 2005. See
 J.A. 11817–18 (Root Decl. ¶ 20). Common sense, and Tele-
 flex’s own testimony, 6 suggest that these documents would
 exist if testing had occurred. Teleflex’s theory is that the
 relevant documents did exist at one time but have since

     6   “In [Jim Kauphusman’s] role [as the primary engi-
 neer working on RX GuideLiner], he’s creating some level
 of work product every day, and, you know, it comes in the
 form of drawings, prototypes, test results, you know, and
 written reports.” J.A. 5244 (Sutton Dep. 36:23–37:2).
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 8           MEDTRONIC, INC.   v. TELEFLEX INNOVATIONS S.À.R.L.

 been destroyed. See J.A. 11817 (Root Decl. ¶ 20); J.A. 5197
 (Erb Dep. 29:13–19). A rule that favors the retention of
 relevant documents does not create an “impossible stand-
 ard” for inventors seeking to enforce a patent for a claimed
 invention.
                               V
     Because the corroborating evidence that the RX Guide-
 Liner prototypes had been tested and shown to work for
 their intended purpose was insufficient, I would reverse
 the Board’s holding that the invention had actually been
 reduced to practice before Itou’s priority date. 7 I respect-
 fully dissent.

     7   The Board also found that Teleflex had demon-
 strated reasonable diligence between Itou’s September 23,
 2005, filing date and the filing date of the RX GuideLiner
 patent application on May 3, 2006. The majority does not
 reach the question of reasonable diligence. I note only that,
 with the exception of two law firm invoices covering work
 for a small portion of the diligence period, the corroborating
 evidence for reasonable diligence is equally lacking during
 the vast majority of the relevant period.