February 05, 2020 Feature

Tethering the Nexus: Framing the Claims for Unclaimed Features and Novelty

Scott F. Peachman

©2020. Published in Landslide, Vol. 12, No. 3, January/February 2020, by the American Bar Association. Reproduced with permission. All rights reserved. This information or any portion thereof may not be copied or disseminated in any form or by any means or stored in an electronic database or retrieval system without the express written consent of the American Bar Association or the copyright holder.

Patent litigators are often told to refrain from characterizing claim language, which defines the boundaries of the invention and should remain free from distortion. But there may come a time when claim language does not quite align with the praise for which an invention receives. For instance, claims drawn to a novel pharmaceutical formulation may only later demonstrate unexpected results in clinical trials. Alternatively, an invention may be repurposed for applications that work surprisingly well. In such situations, patent owners should consider how to frame their claim language to best support evidence of objective indicia of nonobviousness in view of controlling law.

Claim language correlates with evidence of objective indicia of nonobviousness through the doctrine of nexus. Generally, this doctrine requires the patentee to establish (1) that such evidence is commensurate in scope with the claims, and (2) that if the evidence is tied to a specific product, the product embodies the scope of the claims.1 Objective indicia lack a nexus, for example, if they exclusively relate to claim elements that were already known in the art.2 Nor can a nexus exist if objective indicia are due only to unclaimed features of an invention.3 When a proper showing is made, however, a nexus is presumed and the patent challenger must rebut it.4 This presumption is not new to patent law,5 but nonetheless its misapplication has been criticized over the years.6

The U.S. Court of Appeals for the Federal Circuit rearticulated its understanding of nexus law in WBIP, LLC v. Kohler Co. in 2016.7 In doing so, it opened up new avenues for establishing a nexus between evidence of objective indicia and claim language. With an eye toward novelty and unclaimed features, this article describes relevant findings in WBIP and recent Federal Circuit case law regarding nexus, and further elaborates on the presumption of nexus and required commensurateness. Specific cases that apply WBIP to align claim language with objective evidence are then illustrated. Together these sections provide guidance on tethering the nexus between evidence of objective indicia and claim language.

Federal Circuit Guidance on Nexus Law: WBIP and Recent Developments

At issue in WBIP were patents directed to marine engine exhaust systems that reduced the amount of carbon monoxide emissions.8 Although these patents recited elements known in the prior art and the proffered objective evidence related to an unclaimed feature, the Federal Circuit determined that substantial evidence supported a jury’s finding that a nexus existed between objective evidence of nonobviousness and the merits of the invention claimed in the patents.9 The WBIP court indicated that there “is a presumption of nexus for objective considerations when the patentee shows that the asserted objective evidence is tied to a specific product and that the product ‘is the invention disclosed and claimed in the patent.’”10 The court found the patentee’s showing that its products were embodiments of the claimed invention and that its “proffered objective evidence relates to these specific products” was sufficient to establish the presumption for all five objective indicia at issue.11 The burden then fell to the patent challenger to rebut the presumption by presenting evidence that the objective consideration was “due to extraneous factors other than the patented invention,” which include “additional unclaimed features and external factors, such as improvements in marketing.”12

Critical to the finding of nexus in WBIP was the patentee framing the “merits of the claimed invention” as a claimed combination of components that “results in a low-carbon monoxide emission marine gen-set” and that “overcame a specific problem in the marine environment.”13 Although elements of the claimed systems were known in the prior art, the Federal Circuit clarified its prior holding in Rambus Inc. v. Rea14 to find that “it is the claimed combination as a whole that serves as a nexus for the objective evidence.”15 Rambus parallels WBIP in that both cases involved a combination of claim elements that were found to possess novelty and to enable an unclaimed feature of improved performance that overcame a specific problem in the art.16 The WBIP court also cautioned that “[q]uestions of nexus are highly fact-dependent and, as such are not resolvable by appellate-created categorical rules and hierarchies as to the relative weight or significance of proffered evidence.”17

The Federal Circuit more recently in Polaris Industries, Inc. v. Arctic Cat, Inc. revisited an important aspect of the presumption of nexus analysis concerning the requirement for objective evidence to be coextensive—or commensurate in scope—with the claimed invention.18 Building off its decision in WBIP, the Federal Circuit found that the Patent Trial and Appeal Board (PTAB) had erred in not presuming a nexus, as the patentee had provided “undisputed evidence” that its vehicles embodied and were coextensive with the patent claims at issue.19 The Polaris court explained that it was not a requirement for “a patentee and its expert to go further” when the “proffered evidence is not rebutted and the technology is relatively simple.”20 The Polaris court further indicated that the claims at issue “broadly cover the entire vehicle,” as opposed to “only a component of a commercially successful machine.”21

Enforcing Application of the Presumption of Nexus

WBIP has reinforced the evidentiary burden-shifting framework of the presumption of nexus and has helped to curb overly strict analyses of objective indicia. This is demonstrated, for instance, where the Federal Circuit has reversed the PTAB for imposing a “strict requirement” for nexus.22 The Federal Circuit recently found in PPC Broadband, Inc. v. Corning Optical Communications RF, LLC that the PTAB erred when it did not apply a presumption of nexus despite the patent owner presenting undisputed evidence that its product embodied the claimed invention and the PTAB did not explain why the evidence was unpersuasive.23 After remand, the Federal Circuit again reversed the PTAB, finding a “structural error” in burden shifting and stating “[t]hough the Board gave lip service to the presumption we instructed it to apply, it then ignored it.”24

Proper application of the presumption of nexus ensures that “evidentiary failure[s]” by the patent challenger are not unfairly shifted to the patentee when it is not required “to show more.”25 Establishing the presumption of nexus is also advantageous where evidence to rebut the presumption is hard to obtain, for instance when it requires running expensive experiments or conducting clinical tests. Nevertheless, what suffices to rebut the presumption of nexus once it is established is less clear. For instance, the Federal Circuit in May 2019 affirmed a finding of obviousness in BTG International Ltd. v. Amneal Pharmaceuticals LLC26 in which the PTAB acknowledged a presumption of nexus, but determined that the petitioner had rebutted the presumption since it was “not clear” whether commercial success was due to the merits of the patented method.27 The patent owner appealed, arguing that under the evidentiary framework articulated in WBIP the presumption of nexus cannot be displaced when the record is inconclusive and the petitioner has not presented sufficient rebuttal evidence to show that commercial success was due to factors other than the claimed invention.28 The Federal Circuit’s affirmance suggests that the evidentiary burden-shifting framework involved in the presumption of nexus is not overly rigid.

The Contours of the Commensurateness Requirement

Patent challengers have attempted to seize on the commensurateness requirement to argue that the presumption of nexus does not apply when there is a mismatch between the claims and the objective evidence.29 However, as articulated by the Federal Circuit in recent decisions, the presumption attaches when the patentee’s product embodies the claims, and “[t]his is true even when the product has additional, unclaimed features.”30 In other words, objective evidence need not be absolutely commensurate with the claimed invention in order to establish the presumption.31 There is a continuing debate as to how many unclaimed features can be in a product and still be coextensive with the claims, and the Federal Circuit has recently avoided providing further guidance on this issue.32

Unclaimed features in objective evidence may not be commensurate with patent claims in certain instances. One example expressly noted in Polaris is when “the patented invention is only a component of a commercially successful machine or process.”33 In another example, the District of Delaware in Cubist Pharmaceuticals, Inc. v. Hospira, Inc. found there was no nexus between proffered objective evidence of long-felt but unmet need to commercialize daptomycin through a high-yield process when this feature was not recited in the patent claims.34 The Cubist court stated that “[a]lthough the processes described in the purity patents may have ultimately lead to more efficient production, the claims themselves do not speak of yield.”35 A middle ground between these examples of limited commensurateness and absolute identity of scope with the claims is recognized in the nexus law, specifically a requirement that objective evidence of nonobviousness need only be “reasonably commensurate with the scope of the claims.”36

Examples from pharmaceutical patent case law provide further clarity on the contours of the commensurateness requirement. For instance, the District of Delaware in Cephalon Inc. v. Mylan Pharmaceuticals Inc. found that objective evidence relating to a single tested formulation had a nexus with broader claims that encompassed many other embodiments.37 The asserted claims in Cephalon recited mannitol in “an amount between about 10% and about 80%” and sodium starch glycolate (SSG) in “an amount of about 0.25% to 20%.”38 Mylan argued that Cephalon’s assertion of unexpected results based on a single pharmacodynamics study related to a single formulation containing 3 percent SSG and 47–49 percent mannitol was disproportionate in scope to the asserted patent claims.39 Cephalon in rebuttal argued that its objective evidence of unexpected results supported the conclusion that “unexpected results occur over the claimed ranges of SSG and mannitol because those ranges cover typical and reasonable amounts of mannitol and SSG for use in tablet formulations.”40 The court agreed with Cephalon and cited Genetics Institute, LLC v. Novartis Vaccines & Diagnostics, Inc.41 for the proposition that “‘absolute identity of scope’ is not required; rather, unexpected results are rejected ‘where the evidence is plainly disproportionate to the scope of the claim.’”42 The Cephalon court further noted that Mylan had presented no contrary evidence that unexpected results may not occur for higher or lower amounts of mannitol or SSG, and that attorney argument alone was not persuasive for rebuttal.43

A nexus between evidence of commercial success related to a single embodiment and a claim covering multiple embodiments has been found before.44 Other cases involving evidence of unexpected results and broad claims have reached different outcomes;45 however, these examples stem from ex parte proceedings which, unlike inter partes review and district court proceedings, do not involve a presumption of validity or burden-shifting framework. In another district court example, the District of New Jersey in AstraZeneca LP v. Breath Ltd. found that objective evidence of long-felt, unmet need was “not reasonably commensurate with the scope of the claims as it goes to only a single embodiment of the claims.”46 The court went on to explain that “[n]one of the asserted claims are directed to a nebulized inhalation product that is used in the long-term treatment of asthma in young children. Rather, they are much broader in scope.”47 Since AstraZeneca’s evidence of long-felt, unmet need “relates in large part to limitations or elements that do not form part of the asserted claims, there is no evidence to infer that other embodiments of the asserted claims would satisfy that long-felt, unmet need.”48

As expected, tethering evidence of objective indicia to broad claim language can be more difficult to achieve when seeking to establish a nexus. While objective evidence directed to a single embodiment can be sufficient, as shown in Cephalon, other instances such as in AstraZeneca and Cubist reached different outcomes. The District Court for the District of Columbia in Dome Patent, L.P. v. Rea has explained the rationales underlying the commensurateness requirement, stating that a claim must be “nonobvious throughout the range of the patent claim. Evidence of nonobviousness of one embodiment in a broad claim is of limited value, as it leaves open the question of whether other embodiments were obvious.”49 The Dome Patent court further noted that providing “an adequate basis to support the conclusion that other embodiments falling within the claim will behave in the same manner” will generally establish commensurateness.50

A finding of nexus is fortunately not an all or nothing proposal, and evidentiary weight will depend on the facts of the case. For instance, the Federal Circuit in ClassCo, Inc. v. Apple, Inc. found that the PTAB improperly dismissed objective evidence based on an alleged lack of commensurateness between the scope of the claims and praised features in the objective evidence.51 In particular, the patentee’s objective evidence of industry praise related to a single speaker embodiment that was expressly recited in one dependent claim and fell within the scope of two broader claims that encompassed additional embodiments.52 Citing both Rambus and WBIP, the ClassCo court concluded that the PTAB “should have afforded ClassCo’s evidence some weight, taking into account the degree of the connection between the features presented in evidence and the elements recited in the claims.”53 The ClassCo court went on to state that because the two broader claims “are considerably broader than the particular features praised in the articles, it would be reasonable for the Board to assign this evidence little weight. But, contrary to the finding of the Board, the evidence is due at least some weight.”54

Framing the “Merits of the Claimed Invention” to Establish Nexus

Considering the impact of WBIP in nexus jurisprudence and practice over the past three years, it is to the advantage of patentees to best align their claims with the objective evidence and the theories of the case that they seek to advance at trial. As illustrated in WBIP and before in Rambus, correlating evidence of objective indicia to claim elements that collectively are novel over the prior art, and framing this collection of claim elements as overcoming problems in the art that may not be expressly recited in the claims, is a viable strategy for establishing a nexus.

In an inter partes review proceeding decided on the heels of WBIP, the patent owner prevailed using a strategy that tied objective evidence to unclaimed features.55 It took the position that its commercial drug was the first once-daily, controlled-release formulation of mesalamine and that these features were not suggested by the prior art references.56 The patent owner admitted that its proffered objective evidence for three different objective indicia included a feature that was not recited in the claims, specifically a once-daily dose of mesalamine.57 The patent owner explained that it nonetheless was entitled to a presumption of nexus and that objective indicia does not lack a nexus simply because it relates to unclaimed features, with specific reference to both WBIP and Rambus.58

Responding to allegations that its objective indicia related to unclaimed features, the patent owner explained that it was the high content of drug recited in the patent claims and certain aspects of the claimed formulation that enabled once-daily administration.59 The PTAB sided with the patent owner, noting that while certain features of the objective evidence were not recited in the claims, the patent owner had persuasively argued that a claimed feature “leads to” fewer pills per day.60 Despite claims of relatively broad scope61 and objective evidence related to a single embodiment out of numerous potential embodiments within the scope of the claims, the PTAB found that objective indicia of commercial success and industry praise was “relevant and favorable” and of long-felt but unsolved need was “compelling.”62

The PTAB more recently issued its final written decision in Fox Factory, Inc. v. SRAM, LLC, where it found that the instituted patent claims were not obvious.63 At issue in Fox Factory were patent claims directed to bicycle chainrings, as well as bicycle cranksets and drivetrain systems that include chainrings.64 The patent owner submitted evidence that 12 families of its products were covered by the patent claims and related to five objective indicia.65 The petitioner argued that the products included “hundreds of features” that were not claimed in the patent at issue, including features covered by other patents held by the patent owner.66 The PTAB nonetheless found that the patent owner was entitled to a presumption of nexus under WBIP and that the petitioner failed to present rebuttal evidence establishing that objective indicia of nonobviousness was due to “extraneous factors” such as “additional unclaimed factors.”67 The PTAB also relied on Polaris for the concept that claims which broadly cover an entire vehicle, rather than only a component of a successful machine, may receive the presumption of nexus.68 The patent owner argued at the oral hearing that the merits of the claimed invention related to “something special to keep that chainring on” and that was “what all the press is about.”69 The final written decision endorsed the patent owner’s evidence that the claimed chainring itself was what enables unclaimed features of the patent owner’s products.70 This case is on appeal to the Federal Circuit and new developments should be considered.71

Additionally, the District Court of Oregon when deciding a motion for summary judgment in Skedco, Inc. v. Strategic Operations, Inc. reasoned that an unclaimed feature of “portability” was not an “extraneous factor” that disqualified a finding of nexus with objective evidence under WBIP, as the claims read in view of the specification supported the existence of the unclaimed feature.72 The defendant argued that commercial success was due only to the unclaimed portable and concealable nature of the plaintiff’s product.73 The plaintiff successfully argued in rebuttal that portability is one of the merits of the claimed invention contemplated in the specification that results from practicing the claimed invention as a whole.74

Lessons Learned

Federal Circuit precedent in WBIP has provided new avenues to establish a nexus between claim language and objective indicia of nonobviousness. Combined with case law illustrating the presumption of nexus and the contours of the commensurability requirement, patentees and patent challengers have certain considerations for their upcoming patent disputes.

Patentees should consider identifying a combination of claim elements which enable the results seen in evidence of objective indicia and thereby recast the “merits of the claimed invention” as necessary. This may assist in tethering unclaimed features in evidence of objective indicia to claim language and in establishing the presumption of nexus. It should be easier to show that objective evidence is reasonably commensurate with a combination of claimed elements, as opposed to showing that increased sales or unexpected results are related to a single claim element. Moreover, this strategy should also make it more difficult for patent challengers to rebut the presumption of nexus by showing that a combination of claim elements as a whole are disclosed in a single prior art reference and therefore not novel.

Patentees should consider what combinations of claimed features solve unclaimed problems described in evidence of objective indicia. Additionally, patentees should consider pursuing strategic claim constructions and positions that align with evidence of objective indicia and provide the best chance to frame the claim language in order to obtain a presumption of nexus. Patentees should also consider the commensurateness requirement by anticipating the likely challenges and planning to meet them with argument and potentially evidence.

Patent challengers should dispute the presumption of nexus and, if it is established, meet their burden in rebutting the presumption by submitting evidence. Along these lines, patent challengers should anticipate and be prepared to submit appropriate rebuttal evidence. Patent challengers should also be aware of the general argument strategy under WBIP and prepare to undermine such tactics. For instance, patent challengers should identify the areas where patentees are likely to rely on unclaimed features and plan to attenuate any connection with the patent claims with both rebuttal evidence and strategically obtained claim constructions. Patent challengers should also continue to emphasize the absence of unclaimed features in the claims.


1. See, e.g., Polaris Indus., Inc. v. Arctic Cat, Inc., 882 F.3d 1056, 1072 (Fed. Cir. 2018).

2. See Rambus Inc. v. Rea, 731 F.3d 1248, 1257 (Fed. Cir. 2013); Ormco Corp. v. Align Tech., Inc., 463 F.3d 1299, 1312–13 (Fed. Cir. 2006).

3. See WBIP, LLC v. Kohler Co., 829 F.3d 1317, 1329 (Fed. Cir. 2016); Ormco, 463 F.3d at 1312–13.

4. See, e.g., Brown & Williamson Tobacco Corp. v. Philip Morris Inc., 229 F.3d 1120, 1130 (Fed. Cir. 2000).

5. See, e.g., Phillip Morris, 229 F.3d at 1130; Demaco Corp. v. F. Von Langsdorff Licensing Ltd., 851 F.2d 1387, 1392 (Fed. Cir. 1988).

6. See, e.g., Wm. Wrigley Jr. Co. v. Cadbury Adamas USA LLC, 683 F.3d 1356 (Fed. Cir. 2012); id. at 1369–70 (Newman, J., dissenting).

7. 829 F.3d 1317.

8. Id. at 1324–25.

9. Id. at 1324–25, 1329–32.

10. Id. at 1329.

11. Id. at 1329–30.

12. Id. at 1329.

13. Id. at 1331.

14. 731 F.3d 1248 (Fed. Cir. 2013).

15. WBIP, 829 F.3d at 1330–31.

16. Compare WBIP, 829 F.3d at 1329–32, with Rambus, 731 F.3d at 1256–58.

17. WBIP, 829 F.3d at 1331.

18. 882 F.3d 1056, 1072–73 (Fed. Cir. 2018).

19. Id.

20. Id. at 1073.

21. Id.

22. See, e.g., Rambus Inc. v. Rea, 731 F.3d 1248, 1257 (Fed. Cir. 2013); see also Institut Pasteur & Universite Pierre et Marie Curie v. Focarino, 738 F.3d 1337, 1346 (Fed. Cir. 2013).

23. PPC I, 815 F.3d 734, 746–47 (Fed. Cir. 2016).

24. PPC Broadband, Inc. v. Iancu (PPC II), 739 F. App’x 615, 626 (Fed. Cir. 2018).

25. Id.

26. 923 F.3d 1063 (Fed. Cir. 2019).

27. Wockhardt Bio AG v. Janssen Oncology, Inc., No. IPR2016-01582, Paper No. 72, at 42–44 (P.T.A.B. Jan. 17, 2018), aff’d, BTG, 923 F.3d at 1077.

28. Corrected Non-Confidential Opening Brief of Plaintiffs-Appellants at 41–42, BTG, 923 F.3d 1063 (Fed. Cir. filed Jan. 22, 2019) (No. 19-1147).

29. See, e.g., Eagle View’s Response Brief, Xactware Sols., Inc. v. Eagle View Techs., Inc., 755 F. App’x 1015 (Fed. Cir. filed June 29, 2018) (No. 2018-1053), 2018 WL 3304212, at *36–37.

30. See PPC I, 815 F.3d 734, 747 (Fed. Cir. 2016).

31. See Polaris Indus., Inc. v. Arctic Cat, Inc., 882 F.3d 1056, 1071–72 (Fed. Cir. 2018); WBIP, LLC v. Kohler Co., 829 F.3d 1317, 1329–31 (Fed. Cir. 2016); Cephalon Inc. v. Mylan Pharm. Inc., 962 F. Supp. 2d 688, 719 (D. Del. 2013).

32. See Xactware, 755 F. App’x at 1016; Appellant Brief, Xactware, 755 F. App’x 1015 (Fed. Cir. filed Mar. 5, 2018), 2018 WL 1364004, at *21–24, *30–35; Eagle View’s Response Brief, supra note 29, at *1–2, *34–43.

33. Polaris, 882 F.3d at 1072.

34. 75 F. Supp. 3d 641, 672 (D. Del. 2014), aff’d, 805 F.3d 1112, 1130 (Fed. Cir. 2015).

35. Id.

36. Rambus Inc. v. Rea, 731 F.3d 1248, 1257 (Fed. Cir. 2013).

37. 962 F. Supp. 2d 688, 718–20 (D. Del. 2013).

38. Id. at 718.

39. Id. at 720.

40. Id. at 719–20.

41. 655 F.3d 1291 (Fed. Cir. 2011).

42. See Cephalon, 962 F. Supp. 2d at 719 (alterations omitted) (emphasis added); Genetics Inst., 655 F.3d at 1308–09 (finding that the district court did not err in considering objective evidence of unexpected results when asserted claims permitted substitution of up to 10 percent of amino acids in a protein described in the objective evidence, despite opposing counsel providing rebuttal evidence that one embodiment within the scope of the asserted claims did not provide unexpected results).

43. Cephalon, 962 F. Supp. 2d at 720.

44. See, e.g., In re Glatt Air Techniques, Inc., 630 F.3d 1026, 1030 (Fed. Cir. 2011).

45. See, e.g., In re Peterson, 315 F.3d 1325, 1331 (Fed. Cir. 2003); In re Grasselli, 713 F.2d 731, 743 (Fed. Cir. 1983); In re Greenfield, 571 F.2d 1185, 1189 (C.C.P.A. 1978).

46. 88 F. Supp. 3d 326, 389 (D.N.J.), aff’d, 603 F. App’x 999, 1004 (Fed. Cir. 2015).

47. Id.

48. Id.

49. 59 F. Supp. 3d 52, 86 (D.D.C. 2014).

50. Id. at 87 (emphasis omitted).

51. 838 F.3d 1214, 1221–22, 1224 (Fed. Cir. 2016).

52. Id. at 1221.

53. Id.

54. Id. at 1221–22 (emphasis added) (footnote omitted).

55. Coal. for Affordable Drugs II LLC v. Cosmo Techs. Ltd., No. IPR2015-00988, Paper No. 57, at 23–24 (P.T.A.B. Oct. 5, 2016).

56. See Record of Oral Hearing at 49:20–51:20, Cosmo Techs., No. IPR2015-00988, Paper No. 54 (P.T.A.B. Sept. 28, 2016).

57. Id. at 50:7–18.

58. Id. at 49:20–51:20.

59. Id. at 50:7–52:20, 66:24–68:2.

60. Cosmo Techs., No. IPR2015-00988, Paper No. 57, at 23.

61. See U.S. Patent No. 6,773,720 (filed June 8, 2000).

62. Cosmo Techs., No. IPR2015-00988, Paper No. 57, at 23–24.

63. No. IPR2016-01876, Paper No. 59, at 68 (P.T.A.B. Apr. 2, 2018), appeal filed, No. 2018-2024 (Fed. Cir. May 31, 2018).

64. Id. at 3–6, 26–27.

65. Id. at 23–24.

66. Id. at 24–26.

67. Id. at 23–34.

68. Id. at 27.

69. See Record of Oral Hearing at 51:14–52:3, Fox Factory, No. IPR2016-01876, Paper No. 58 (P.T.A.B. Feb. 9, 2018).

70. See Fox Factory, No. IPR2016-01876, Paper No. 59, at 31, 38–39.

71. Fox Factory, Inc. v. SRAM, LLC, No. 2018-2024 (Fed. Cir. filed May 31, 2018).

72. 287 F. Supp. 3d 1100, 1133–35 (D. Or. 2018).

73. Id. at 1133.

74. Id. at 1133–34.


Scott F. Peachman is a senior associate in Paul Hastings’s Life Sciences IP Litigation practice. His practice focuses on high-stakes patent litigation matters in the chemical and pharmaceutical arts.