Case: 21-1967 Document: 59 Page: 1 Filed: 09/07/2022
`United States Court of Appeals
`for the Federal Circuit
`Appeal from the United States District Court for the
`District of Delaware in No. 1:20-cv-01483-LPS, Judge
`Leonard P. Stark.
`Decided: September 7, 2022
`KEMPER DIEHL, Susman Godfrey LLP, Seattle, WA, ar-
`gued for plaintiff-appellant. Also represented by SETH
`P.C., Washington, DC, argued for defendants-appellees.
`Also represented by STEVEN KATZ, Boston, MA.


`Case: 21-1967 Document: 59 Page: 2 Filed: 09/07/2022
`Before PROST, CHEN, and STOLL, Circuit Judges.
`PROST, Circuit Judge.
`Arendi S.A.R.L. (“Arendi”) alleged that various LG
`Electronics Inc. and LG Electronics USA, Inc. (collectively
`“LG”) products infringed its U.S. Patent No. 7,917,843
`(“the ’843 patent”). First Am. Compl., Arendi S.A.R.L. v.
`LG Elecs. Inc. (“Arendi I”), No. 1:12-cv-01595 (D. Del.
`Oct. 3, 2013), ECF No. 34; see also J.A. 144–57 (original
`complaint). After the district court struck part of Arendi’s
`infringement expert report as beyond the scope of Arendi’s
`infringement contentions, Arendi filed a second patent-in-
`fringement suit against LG in the same court, again assert-
`ing the ’843 patent. Compl. for Patent Infringement,
`Arendi S.A.R.L. v. LG Elecs. Inc. (“Arendi II”), No. 1:20-cv-
`01483 (D. Del. Nov. 3, 2020), ECF No. 1; J.A. 1583–91.
`The district court granted LG’s motion to dismiss the Ar-
`endi II complaint under the duplicative-litigation doctrine,
`determining that in both cases the same products were ac-
`cused of infringing the same patent. Arendi appeals from
`the dismissal. We affirm.
`In Arendi I, Arendi sued LG (among others) in the U.S.
`District Court for the District of Delaware for infringing
`various Arendi patents. The District of Delaware, Arendi’s
`chosen forum, has specific rules governing initial discovery
`in patent cases. Section 4(a) of those rules required Arendi
`to “specifically identify the accused products and the as-
`serted patent(s) they allegedly infringe.” D. Del. Default
`Standard for Discovery § 4(a) (cleaned up). Then, under
`Section 4(c), Arendi had to “produce . . . an initial claim
`chart relating each accused product to the asserted claims
`each product allegedly infringes” after LG provided initial
`discovery on those products. Id. § 4(c) (emphasis added);
`see id. § 4(b). As explicitly outlined in the same local rules,
`“these disclosures are ‘initial,’ [and] each party shall be
`permitted to supplement.” Id. § 4 n.3.


`Case: 21-1967 Document: 59 Page: 3 Filed: 09/07/2022
`Arendi filed its Section 4(a) Disclosure in Novem-
`ber 2018 and listed hundreds of LG products as infringing
`four claims of the ’843 patent. J.A. 1121–37 (Section 4(a)
`Disclosure). Despite this lengthy 4(a) Disclosure and Sec-
`tion 4(c)’s instruction that Arendi “relat[e] each accused
`product to the asserted claims,” Arendi’s Section 4(c) Dis-
`closure provided claim charts for only one of those prod-
`ucts—LG’s Rebel 4 phone. These charts labeled the
`Rebel 4 as “exemplary.” J.A. 1167–262 (Section 4(c) Disclo-
`In April 2019, two months after Arendi filed its Sec-
`tion 4(c) Disclosure, LG sent a letter to Arendi stating that
`the singular-product claim charts for the ’843 patent were
`insufficient under Section 4(c) and thus “LG underst[ood]
`Arendi’s infringement contentions [for the ’843 patent] to
`be limited to” the Rebel 4. J.A. 1469. LG remarked that,
`“[s]hould Arendi intend to accuse [non-Rebel 4] products,
`then Arendi must promptly provide claim charts demon-
`strating how these products infringe[] or explain why Ar-
`endi contends the current claim charts are representative
`of specific non-charted products.” J.A. 1469. Arendi did
`not respond to this letter or move to supplement its Sec-
`tion 4(c) Disclosure.
`As the litigation proceeded, Arendi and LG agreed on
`eight representative products to represent all accused
`products. Seven of the eight were non-Rebel 4 products.
`LG provided additional discovery on all eight representa-
`tive products, and Arendi still did not move to supplement
`its Section 4(c) Disclosure. So in October 2019, in response
`to an interrogatory relating to those eight products, LG re-
`iterated its “position that Arendi has only provided in-
`fringement contentions for [the Rebel 4]. . . . Arendi bears
`the burden to prove infringement and, if it so desires, to try
`to prove that” the Rebel 4 “is representative of one or more”
`of the non-Rebel 4 products. J.A. 1476. Without such a
`showing, LG continued, “Arendi has not provided suffi-
`ciently detailed contentions to know . . . its allegations of


`Case: 21-1967 Document: 59 Page: 4 Filed: 09/07/2022
`infringement” for the ’843 patent. J.A. 1476–77. Still, Ar-
`endi did not move to supplement its Section 4(c) Disclosure.
`Arendi provided its expert report in August 2020 after
`the close of fact discovery in December 2019. LG moved to
`strike portions of that report because it allegedly “dis-
`closed—for the first time—infringement contentions for
`five of” the seven non-Rebel 4 representative products.
`J.A. 191 (emphasis omitted); see Arendi I, ECF No. 201.
`The district court orally granted that motion in Octo-
`ber 2020 under applicable Third Circuit law. The court de-
`termined that Arendi did not timely disclose these
`infringement contentions having “failed to fulfill its discov-
`ery obligations.” J.A. 1576–77 (citing Meyers v. Pennypack
`Woods Home Ownership Ass’n, 559 F.2d 894 (3d Cir.
`1977)). In the court’s analysis, it repeated LG’s assertion
`that “LG understood Arendi was accusing only the Rebel 4”
`of infringing the asserted ’843 patent claims, J.A. 1577,
`since Arendi repeatedly failed to update its infringement
`contentions in the face of LG’s April 2019 letter and Octo-
`ber 2019 interrogatory response. Arendi still took no action
`to supplement its Section 4(c) Disclosure.
`Instead, Arendi filed its Arendi II complaint in Novem-
`ber 2020 in the District of Delaware. This complaint also
`asserted that LG’s non-Rebel 4 products infringed the ’843
`patent. LG moved to dismiss the complaint as duplicative
`since all of the non-Rebel 4 products accused in Arendi II
`were also accused in Arendi I. The district court granted
`that motion without prejudice via an oral order in
`April 2021, J.A. 3, 50–64, and Arendi appealed on May 18,
`That same day, Arendi finally moved to supplement its
`Section 4(c) Disclosure in Arendi I. In March 2022, the dis-
`trict court denied that motion and a pending LG motion for
`summary judgment of noninfringement of the non-Rebel 4
`products without prejudice “[i]n view of the potential im-
`pact of [this] pending appeal.” Arendi I, ECF No. 354. The


`Case: 21-1967 Document: 59 Page: 5 Filed: 09/07/2022
`court also noted that the motions were subject to renewal
`after a decision in this appeal. Id.
`We have jurisdiction under 28 U.S.C. § 1295(a)(1).
`For a “procedural question that is not unique to [our]
`exclusive jurisdiction,” this court applies and gives “defer-
`ence for regional circuit law on a concern for ‘consistency of
`future trial management.’” Eolas Techs., Inc. v. Microsoft
`Corp., 457 F.3d 1279, 1282 (Fed. Cir. 2006) (quoting Biodex
`Corp. v. Loredan Biomedical, Inc., 946 F.2d 850, 857–58
`(Fed. Cir. 1991)). Under the circumstances of this case, the
`question of dismissing the Arendi II complaint as duplica-
`tive of the Arendi I complaint involves a procedural issue:
`a district court’s power to dismiss a case as duplicative is
`“part of [a district court’s] general power to administer its
`docket,” Fabics v. City of New Brunswick, 629 F. App’x 196,
`198 (3d Cir. 2015) (nonprecedential), that supports “wise
`judicial administration,” Serline v. Arthur Andersen & Co.,
`3 F.3d 221, 223 (7th Cir. 1993), and “conservation of re-
`sources,” Adam v. Jacobs, 950 F.2d 89, 92 (2d Cir. 1991).
`We, therefore, apply the Third Circuit’s standard of review-
`ing dismissals of duplicative complaints for abuse of discre-
`tion. See Jenn-Ching Luo v. Owen J. Roberts Sch. Dist.,
`737 F. App’x 111, 115 n.4 (3d Cir. 2018) (nonprecedential);
`Fabics, 629 F. App’x at 198; Schneider v. United States,
`301 F. App’x 187, 190 (3d Cir. 2008) (nonprecedential). A
`district court abuses its discretion when it reaches an er-
`rant conclusion of law, improperly applies law to fact, or
`makes a clearly erroneous finding of fact. Weitzner v.
`Sanofi Pasteur Inc., 909 F.3d 604, 613 (3d Cir. 2018).
`The duplicative-litigation doctrine prevents plaintiffs
`from “maintain[ing] two separate actions involving the
`same subject matter at the same time in the same court . . .
`against the same defendant.” Walton v. Eaton Corp.,


`Case: 21-1967 Document: 59 Page: 6 Filed: 09/07/2022
`563 F.2d 66, 70 (3d Cir. 1977) (en banc). Whether the Ar-
`endi I and Arendi II patent-infringement complaints in-
`volve the same subject matter is determined under Federal
`Circuit law. Senju Pharm. Co. v. Apotex Inc., 746 F.3d
`1344, 1348 (Fed. Cir. 2014).1 “[A] cause of action is defined
`by the transactional facts from which it arises[] and the ex-
`tent of the factual overlap.” Id. at 1349. There are two
`primary “areas of factual overlap” to consider in this anal-
`ysis: (1) “the overlap of the product[s] . . . accused in the in-
`stant action with the product[s] . . . accused in the prior
`action”; and (2) the overlap of the patents in both suits. Id.
`1 Senju Pharmaceutical involved an issue of claim
`preclusion—also known as res judicata—a doctrine that
`precludes later “repetitious suits involving the same cause
`of action” after a prior suit has reached a final judgment.
`Senju Pharm., 746 F.3d at 1348 (quoting C.I.R. v. Sunnen,
`333 U.S. 591, 597 (1948)). The duplicative-litigation doc-
`trine does not require a final judgment to bar a later com-
`plaint, but it does involve a similar inquiry in that it also
`looks to whether the later complaint is, essentially, repeti-
`tious. See Adams v. Cal. Dep’t of Health Servs., 487 F.3d
`684, 688–89 (9th Cir. 2007) (“To determine whether a suit
`is duplicative, we borrow from the test for claim preclu-
`sion.”); Hartsel Springs Ranch of Colo., Inc. v. Bluegreen
`Corp., 296 F.3d 982, 987 n.1 (10th Cir. 2002) (“[I]n the [du-
`plicative-litigation] context, the appropriate inquiry is
`whether, assuming that the first suit were already final,
`the second suit could be precluded pursuant to claim pre-
`Given the particular facts of this case, though, we also
`recognize an argument can be made that whether the Ar-
`endi II complaint is duplicative of the Arendi I complaint
`concerns an understanding of the case’s procedural history
`and the application of local rules rather than an issue pe-
`culiar to patent law. But we need not explore this further
`because the result would be the same either way.


`Case: 21-1967 Document: 59 Page: 7 Filed: 09/07/2022
`(emphasis omitted). The only issue in this appeal is
`whether the district court properly applied that law to the
`facts of this case.
`The district court determined that Arendi II was “im-
`properly duplicative of Arendi I.” J.A. 50–51 (italics added)
`(citing Walton, 563 F.2d at 70). As the district court ex-
`plained, under applicable Federal Circuit law, cases in-
`volve the same subject matter “where the same patent is
`asserted and the accused products are at least essentially
`the same or identical.” J.A. 51–52 (citing Senju Pharm.,
`746 F.3d at 1348). The district court reasoned that, since
`“[i]t’s undisputed that . . . the same products . . . are al-
`leged to infringe the same patent” in both cases, “here,
`we’re in the identical[-product] situation.” J.A. 51–52.
`Arendi challenges the district court’s determination
`that Arendi I and Arendi II involve the same subject mat-
`ter. Arendi does not contest that it asserts the same patent
`in Arendi I and Arendi II, nor could it. Arendi does, how-
`ever, dispute that the products it accused in Arendi II are
`“identical” to products it accused in Arendi I.
`Arendi tries to argue that the products accused in Ar-
`endi I and Arendi II are not identical because there is no
`overlap between the accused products. Arendi asserts that
`this lack of overlap is a consequence of the district court’s
`grant of LG’s motion to strike parts of Arendi’s expert re-
`port in Arendi I. According to Arendi, the district court de-
`termined that Arendi had not sufficiently disclosed its
`intent to accuse the non-Rebel 4 products in Arendi I such
`that those products were effectively not at issue. See Oral
`Arg. at 2:13–3:40 (citing J.A. 1576–77).2 And under this
`logic, Arendi maintains, there is no accused-product
`2 No. 21-1967, https://oralarguments.cafc.uscourts.g


`Case: 21-1967 Document: 59 Page: 8 Filed: 09/07/2022
`overlap: the non-Rebel 4 products accused in Arendi II can-
`not be identical to products accused in Arendi I because Ar-
`endi I involves only LG’s Rebel 4 phone. See Appellant’s
`Br. 21–22, 27.
`But Arendi misunderstands (if not misrepresents) the
`district court’s Arendi I order. As the district court ex-
`plained when dismissing the Arendi II complaint, although
`Arendi insists the district court “ruled” that the non-Re-
`bel 4 products “had not been accused in Arendi I,” “[t]hat is
`not correct.” J.A. 54 (italics added). The court did not grant
`LG’s motion to strike parts of Arendi’s infringement expert
`report because Arendi failed to sufficiently accuse the non-
`Rebel 4 products. The court granted the motion to strike
`because Arendi “failed to fulfill its discovery obligations”
`with respect to those products, so Arendi’s infringement al-
`legations in its expert report were procedurally untimely.
`J.A. 1576–77.
`And it’s hard to find any basis whatsoever for Arendi’s
`assertion that the non-Rebel 4 products were never “at is-
`sue” or “litigated” in Arendi I. Appellant’s Br. 22, 25. Ar-
`endi listed the non-Rebel 4 products in its Section 4(a)
`Disclosure, served interrogatories about the non-Rebel 4
`products after the parties agreed to seven non-Rebel 4 rep-
`resentative products, received discovery related to those
`products, and included non-Rebel 4 products in its expert
`report. See Oral Arg. 7:02–50 (Arendi admitting that it
`considered all products to be at issue when it served its ex-
`pert report). Indeed, those non-Rebel 4 products are the
`focus of Arendi and LG’s renewable motions in Arendi I.
`Under these circumstances, it is apparent that the non-Re-
`bel 4 products were “at issue” or “litigated” in Arendi I.
`So what’s left? It is Arendi’s argument that the non-
`Rebel 4 products are “materially different” than the Re-
`bel 4. Appellant’s Br. 21–22. But again, this argument
`fails because it does not pertain to the question at issue in
`this appeal: comparing the Rebel 4 with non-Rebel 4


`Case: 21-1967 Document: 59 Page: 9 Filed: 09/07/2022
`products says nothing about the overlap between the non-
`Rebel 4 products accused in Arendi I and the non-Rebel 4
`products accused in Arendi II. And it is this latter compar-
`ison that governs whether the Arendi II complaint is dupli-
`cative.3 Senju Pharm., 746 F.3d at 1349.
`Left with the simple and obvious fact that the non-Re-
`bel 4 products accused in Arendi II are identical to products
`accused in Arendi I, we determine that the district court
`did not err in dismissing the Arendi II complaint as im-
`properly duplicative.
` We have considered Arendi’s remaining arguments but
`find them unpersuasive. For the foregoing reasons, we af-
`firm the district court’s dismissal of the complaint.
`3 At oral argument, Arendi requested that this court
`at least opine on the former comparison to “give guidance
`to the district court” in Arendi I. Oral Arg. at 31:58–32:55.
`We consider this request unusual, to say the least, and un-
`surprisingly decline to comment on issues outside of this

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