Blog January 17, 2023
Biosimilars 2022 Year in Review
by Kenneth Darby and Rick Bisenius
This article originally appeared in Volume 18, Issue 4 of the PTAB Bar Association Law Journal in collaboration with the Chicago-Kent Journal of Intellectual Property.
Patent litigants on both sides of the docket struggle with claim limitations that do not expressly recite "means for" language yet define the scope of the invention in terms of functionality rather than structure. In the wake of Williamson v. Citrix Online, LLC,  tribunals have increasingly found that claim limitations reciting so-called nonce words overcome the legal presumption against 112, ¶ 6 (or means-plus-function) treatment. Unsurprisingly, petitioner-defendants generally prefer narrow interpretations of such nonce-word claim limitations under 112, ¶ 6 for purposes of establishing non-infringement and indefiniteness defenses in district court. Yet these same interpretations are often more difficult to address at the Patent Trial and Appeal Board ("PTAB") where infringement and indefiniteness are not at issue. Conversely, patent owners, for their part, are more apt to oppose narrowing 112, ¶ 6 constructions in district court as plaintiffs, but would often like the PTAB to hold petitioners to their district court interpretations if doing so would mean a denial of institution. These conflicting forum-specific interests of the parties raise difficult issues, which panels tend to resolve ad hoc. Trends, guidelines, and the existing rules at the PTAB only expand the cloud of uncertainty.
This Article briefly discusses the Williamson decision, its legal and practical effect, and strategic considerations for petitioners and patent owners at the PTAB.
The Federal Circuit’s En Banc Williamson Decision and the Rise of 112, ¶ 6 Interpretations for Nonce Terms
The 1952 Patent Act incorporated 112, ¶ 6 to provide a mechanism for facilitating purely functional claim limitations. Its promulgation was directly responsive to the Supreme Court's holding in Halliburton Oil Well Cementing Co. v. Walker, which prohibited functional claiming. Pre-AIA 112, Â¶ 6 reintroduced a way to include purely functional limitations, but tethered such limitations to structure(s) recited in the specification (or equivalents thereof). Interpretation of claim elements as reciting purely functional language had, prior to Williamson v. Citrix Online, LLC, traditionally only been applied to claim recitations including the terms "means of" or "means for." However, there was a growing body of law saying that "nonce words" other structureless words in addition to "means" can also sometimes invoke 112, ¶ 6.
On June 16, 2015, a majority opinion from the en banc Federal Circuit in Williamson abruptly abandoned the prior line of jurisprudence addressing the applicability of pre-AIA 35 U.S.C. 112, ¶ 6. In the Williamson majority opinion, penned by Circuit Judge Linn, the court confirmed the traditional presumption against the application of 112, ¶ 6 when a claim term lacks the word "means," but questioned its more recent development of "a heightened bar to overcoming [this] presumption."
The Federal Circuit has long held that absence of the word "means" creates a presumption against application of 112, ¶ 6. Several subsequent decisions characterized the presumption against construing non-"means" claims under 112, ¶ 6 as a strong one and had applied it vigorously. Prior to Williamson, the court had expressed repeated skepticism that non-means terms would be construed under 112, ¶ 6, repeatedly tightening the standard for doing so. For example, in Lighting World, Inc. v. Birchwood Lighting, Inc., the court stated for the first time that the negative presumption "is a strong one that is not readily overcome." In Flo Healthcare Solutions, LLC v. Kappos, the court went even further, stating that 112, Â¶ 6 would not be applied to a non-means claim term "without a showing that the limitation essentially is devoid of anything that can be construed as structure."
Sitting en banc, the Williamson court disagreed, finding that "such a heightened burden is unjustified," and "ha[d] resulted in a proliferation of functional claiming untethered to 112, ¶ 6 and free of the strictures set forth in the statute." Expressly overruling Lighting World and its progeny, the court announced a return to the standard of the presumption that had been set forth in prior decisions namely, "whether the words of the claim are understood by persons of ordinary skill in the art to have a sufficiently definite meaning as the name for structure."  Under this more flexible standard, the en banc court explained, "[w]hen a claim term lacks the word 'means,' the presumption can be overcome and 112, ¶ 6 will apply if the challenger demonstrates that the claim term fails to 'recite sufficiently definite structure' or else recites 'function without reciting sufficient structure for performing that function.'"
Applying this standard to the facts of the case, the Williamson court compared two sets of independent claims, one with the term "means" and one with the term "module," and found the non-means claim term "distributed learning control module" deserved 112, ¶ 6 treatment, reasoning that the trigger term "means" had merely been replaced by another word "module" that was equally meaningless. The court went on to broadly suggest that such generic nonce words, like "module," "mechanism," "element," and "device," are in this context "reflect[ive] [of] nothing more than verbal constructs" that "typically do not connote sufficiently definition structure and therefore may invoke 112, ¶ 6." The court left the list of which types of words might be considered nonce words open, but also did not suggest that the listed words themselves were more likely than any others to overcome the presumption.
In the years following Williamson, Federal Circuit panels have reached similar conclusions, finding claim terms that replace the word "means" with a nonce word to be subject to interpretation under 112, ¶ 6 when the presumption against such treatment, as restated under Williamson, was overcome. For example, in Media Rights Technologies, Inc. v. Capital One Financial Corp., the term "compliance mechanism" was so construed, as was the term "symbol generator" in Advanced Ground Information Systems v. Life360, Inc., and "cheque standby unit" in Diebold Nixdorf, Inc. v. International Trade Commission. Williamson thus opened the door to many more non-"means" terms being construed as means-plus-function limitations, albeit still with a presumption to overcome against doing so.
The trickle-down effect of Williamson at the district court and post- grant level has been significant. While a detailed statistical breakdown is beyond the scope of this Article, the authors have identified more than 100 district court cases and 60 post-grant PTAB cases addressing the negative presumption as restated in Williamson far more of which found the presumption overcome than the cases that had addressed this question before Williamson. Meanwhile, the PTAB is required by regulation to address the construction of means-plus-function claim limitations differently than for other claims, which has led to complex claim construction issues prior to institution that have roiled panels and surprised some practitioners.
Seeking consistent application of the 112, ¶ 6 presumptions under Williamson, the United States Patent and Trademark Office ("USPTO") recently promulgated official guidance entitled EXAMINING COMPUTER- IMPLEMENTED FUNCTIONAL CLAIM LIMITATIONS FOR COMPLIANCE WITH 35 U.S.C. 112 ("the Guidance"). In this document, meant to guide patent examiners, the USPTO refers to a 3-prong analysis set forth in the Manual of Patent Examining Procedure for addressing the applicability of 112, Â¶ 6. Exemplary nonce words in the Williamson sense identified in the Guidance include "mechanism," "module," "device," "unit," "component," "element," "member," "apparatus," "machine," and "system." While the Guidance does not specifically mention PTAB trials, some have predicted that it will eventually play a significant role in that setting.
Thinking Through Williamson Strategies and Tactics at the PTAB
In the wake of both Williamson and the new USPTO guidance, practitioners should anticipate treatment of claim terms as purely functional under 112, ¶ 6 to increase and develop strategies for addressing such situations.
Strategy Considerations for Petitioners
In post-grant proceedings, the petitioner carries the ultimate burden of persuasion to establish unpatentability by a preponderance of the evidence. This burden never shifts to the patent owner, though in limited circumstances the burden of production may shift between the parties. The PTAB's rules require the petition to identify "[h]ow the challenged claim is to be construed" and "[h]ow the construed claim is unpatentable," but PTAB practice and Federal Circuit cases urge the PTAB only to construe claims necessary to resolve the issues before it. The rules, however, require the PTAB to address claim construction for means-plus-function limitations differently than for other limitations: "Where the claim to be construed contains a means-plus-function or step-plus-function limitation as permitted under 35 U.S.C. 112(f), the construction of the claim must identify the specific portions of the specification that describe the structure, material, or acts corresponding to each claimed function."
Owning both to the statutory burden of persuasion and to the regulatory requirements for construing these limitations, a petitioner may be forced to take a position, in the petition, on whether a non-means term including a nonce word should be interpreted under 112, ¶ 6 based on Williamson or instead given its plain meaning in view of the specification. If the former, the petition potentially must identify the corresponding structure and demonstrate its presence in the prior art to prevail.
This may be easier said than done. For example, the specification may, in the petitioner's view, not provide corresponding structure, rendering the claim indefinite, and potentially leading to a denial of institution in inter partes review ("IPR") proceedings, which are limited to anticipation and obviousness grounds. This issue can be particularly problematic in the context of computer-implemented inventions, where the corresponding structure in many instances must include a specific algorithm. And even where the specification provides the corresponding structure, the petitioner may struggle to fit its prior art to the 112, ¶ 6 interpretation. This too could lead to denial of institution or, worse, to a final written decision finding the claims not proven unpatentable. As for the opposite tactic of arguing against a 112, ¶ 6 interpretation, petitioners may find this option unpalatable for other reasons. For example, it may foreclose (or at least undermine) a non-infringement or indefiniteness defense in co-pending district court proceedings.
These difficulties may tempt petitioners to avoid specific constructions of non-means claim terms altogether. But, this may also lead them astray. For example, the PTAB has occasionally performed the Williamson analysis sua sponte and determined not to institute a trial, either because the petitioner did not construe the claim and map the prior art to the corresponding structure,  or because the claim term was indefinite for lack of corresponding structure in the specification. In other cases, the PTAB has faulted petitioners for pursuing 112, ¶ 6 interpretations in district court under Williamson and not advancing the same at the PTAB. This issue is all the more important now that the PTAB has adopted a Phillips construction standard to promote consistency between the forums. So, where it may have been once appropriate (if risky) to rely on the tenet that a broadest reasonable interpretation must necessarily encompass a patent owner's infringement allegations as justification for advancing inconsistent claim construction positions, that distinction no longer exists.
The perils of seeking review of non-means claim terms possibly subject to 112, ¶ 6 treatment under Williamson are many. Petitioners should, therefore, identify any such terms early on and develop a strategy that accounts for potential outcomes at the PTAB and in any district court proceedings well before the petition is drafted.
There are several strategies a petitioner could employ. For example, if the prior art will not adequately address the challenged claims under a 112, ¶ 6 construction, or if the underlying specification lacks corresponding structure, then the petitioner could forego an IPR challenge. This is particularly apt when a 112, ¶ 6 construction is necessary to support an essential non-infringement or indefiniteness defense in a co-pending district court proceeding, as it relieves the petitioner from having to play both sides of the Williamson issue. Moreover, under the PTAB's new all-or-nothing institution procedure in view of SAS Institute, Inc. v. Iancu, 138 S. Ct. 1348 (2018), removing claims from the petition that are vulnerable to denial can serve to protect other unaffected claims or at least prevent those claims from being found not unpatentable in a final written decision. When a petitioner does not view a 112, ¶ 6 construction as mission-critical to a district court defense, it may be advisable to affirmatively argue and present evidence that preempts a rebuttal of the negative Williamson presumption. Several petitioners have done so and earned institution.
If the prior art clearly demonstrates unpatentability even under a 112, ¶ 6 construction then the petitioner could include at least one ground directed to such a construction. It is permissible (and generally prudent) to advance multiple grounds or arguments based on potential alternative constructions.
If the prior art is defensible but significantly weaker when applied against a 112, ¶ 6 construction, or if there is some uncertainty as to whether the negative Williamson presumption can be overcome, then the petitioner could forego an express construction, while mapping the prior art to structures recited in the specification element-by-element. This approach is complex and may be vulnerable to an attack by the patent owner for failing to construe the claim properly, or fully map the prior art to the corresponding structure (or its equivalents). There is, however, a sufficient factual predicate regarding the corresponding structure in the petition for the petitioner to leverage in a reply brief, or a request for rehearing. This strategy is perhaps most likely to succeed when a petition is filed well before any claim construction briefing in co-pending district court proceedings, thus preventing or at least defusing any critiques from the patent owner about the petitioner taking inconsistent positions.
Another strategy is to argue preemptively that it would be improper for the PTAB to consider a 112, ¶ 6 construction of non-means terms absent an evidence-based challenge from the patent owner that overcomes the negative Williamson presumption. Such an argument flows from the Federal Circuit's traditional view that the presumptions concerning application of 112, ¶ 6 are rebuttable by intrinsic and extrinsic evidence advanced by a "challenger" in the form of a party in the case. This strategy does not hide from the fact that the petitioner is seeking a 112, ¶ 6 interpretation in district court as part of a defense, which undercuts any arguments from the patent owner that petitioner is taking inconsistent positions or has failed to construe the claims. In this scenario, the patent owner may be unlikely to accept the petitioner's invitation to argue in favor of a 112, ¶ 6 construction if it would undermine their infringement read in district court by narrowing the claims. This strategy was successfully employed, for example, in WhatsApp Inc. v. TriPlay Communications Ltd., where the petition was instituted after presenting plain-meaning interpretations, despite the petitioner having argued for 112, ¶ 6 constructions in its opening claim construction brief in district court several months earlier. There, the broadest reasonable claim construction standard applied, but the PTAB instituted the case based on the patent owner not presenting sufficient evidence to overcome the presumption against such a construction before the PTAB.
Strategy Considerations for Patent Owners
A few strategies based on the state of means-plus-function claim construction under Williamson may also be available to patent owners. While patent owners do not carry the burden of persuasion and need not even file a response of any kind to prevail strategic thinking and early action as to potential non-means 112, ¶ 6 claim terms can pay dividends. For example, inconsistencies between a petitioner's PTAB and district court constructions can be leveraged to argue for denial of institution. Or if a 112, ¶ 6 construction is not detrimental to its infringement case, a patent owner may advance such a construction to argue for denial of institution in view of petitioner's failure to construe a key claim term,  or to undermine petitioner's prior art analysis. On the other hand, a patent owner might affirmatively argue against application of 112, ¶ 6 to secure a plain meaning construction that is more favorable for infringement purposes. District courts may be more likely to consider claim construction rulings from the PTAB now that both forums are operating under the same claim construction standard.
As with almost any argument, the facts and context of the case will heavily influence decision-making for all parties. But with early identification of potential 112, ¶ 6 issues implicated by Williamson, petitioners can increase their chances of success, maintain consistency across district court, ITC, and PTAB proceedings, and avoid costly blunders.
The opinions expressed are those of the authors on the date noted above and do not necessarily reflect the views of Fish & Richardson P.C., any other of its lawyers, its clients, or any of its or their respective affiliates. This post is for general information purposes only and is not intended to be and should not be taken as legal advice. No attorney-client relationship is formed.
Blog January 17, 2023
Biosimilars 2022 Year in Review
Article December 22, 2022
Attorneys Dorothy Whelan, Karl Renner, and Casey Kraning, Ph.D., Author National Law Journal Article "A Look Back on a Decade of Practice at the PTAB"
Article October 20, 2022
Article October 5, 2022
Article October 5, 2022
Article October 5, 2022
Article October 5, 2022
Article October 5, 2022
Article September 29, 2022
Article September 20, 2022