Patent Basics: Practice Tips for Achieving Success in Inter Partes Reviews

“In the intricate landscape of inter partes review proceedings, meticulous attention to detail and strategic thinking are key.”

inter partes reviewInter partes review (IPR) is a legal process conducted before the Patent Trial and Appeal Board (PTAB) to assess patentability based on anticipation or obviousness using prior art publications and patents. Congress established IPR to offer an efficient alternative to litigating patent disputes before the district courts. This article discusses some practice tips for both challenging and defending patents in IPRs before the PTAB.

  1. Petition

The petition represents the linchpin of an IPR, with the petitioner carrying the burden of demonstrating with precision why the challenged patent claims lack patentability. See Harmonic Inc v. Avid Tech., Inc., 815 F.3d 1356, 1363 (Fed. Cir. 2016). Unlike notice pleading, where general statements may suffice, an IPR petition requires technically focused arguments rooted in facts and case law. Given the PTAB judges’ expertise in patent law and technology, your petition must have detailed arguments that satisfy all the legal requirements for establishing unpatentability. Any gap in your presentation is likely to result in the denial of institution of your petition.

Every claim limitation of the challenged claims should be addressed, including those in the dependent claims. It would be ill advised to rely on the general knowledge of a person skilled in the art (POSA) to supply missing limitations. Instead, to the extent necessary, explain how a POSA, based on their knowledge, would understand that the prior art teaches the claimed limitations. See Samsung Elec. Co. v. Lynk Labs, Inc., IPR2022-00100, Paper 30 at 34-35 (PTAB June 7, 2023) (finding that the petitioner appropriately used the “background knowledge possessed by” a POSA to explain that a POSA would understand prior art teachings to disclose a claim limitation).

  1. Crafting Arguments for Obviousness

Arguments regarding obviousness require meticulous articulation, particularly concerning motivation to combine. A statement that there was anticipated success in combining references is insufficient to establish that a POSA would have been motivated to combine them. See Hulu, LLC v. Soundview Innovations, LLC, IPR2018-00582, Paper 34 at 22 (PTAB Aug. 5, 2019) (informative). A bald statement that an element was “an obvious design choice” rarely works. See FanDuel Inc. v. Interactive Games LLC, IPR2017-01491, Paper 38 at 40-42 (PTAB Nov. 20, 2018). Similarly, conclusory statements that it would have taken routine experimentation to achieve the claimed invention would not be persuasive. See Hulu, IPR2018-00582, Paper 34 at 22. Instead, you must present evidence based on prior art and/or expert technical reasoning detailing why a skilled artisan would have been motivated to make the proposed combinations or modifications.

The petitioner must also not forget to present evidence establishing a reasonable expectation of success. This is a crucial element for establishing obviousness that is often overlooked.

  1. Secondary Considerations

While in district court litigations the patent owner usually bears the burden of producing evidence of secondary considerations, in an IPR proceeding, the petitioner must address “known” evidence of secondary considerations, such as evidence presented in the specification, prosecution history, reexamination, or parallel or prior litigations. See Stryker Corp. v. KFX Medical, LLC, IPR2019-00817, Paper 10 at 28 (PTAB Sep. 16, 2019). Ignoring such evidence in your petition risks denial of institution. Id.

For patent owners, establishing secondary considerations may also be challenging. PTAB judges are known to dismiss evidence of secondary considerations when the legal criteria are not strictly satisfied. Evidence presented must be tied to and “reasonably commensurate with the scope of the claims.” Lectrosonics, Inc. v. Zaxcom, Inc., IPR2018-01129, Paper 33 at 32 (PTAB Jan. 24, 2020) (precedential). Further, proving unexpected results requires a comparison with the closest prior art. See Eli Lilly and Co. v. Teva Pharms. Int’l, GmbH, IPR2018-01422, IPR2018-01423, IPR2018-01425, 2020 WL 806932 *57 (PTAB Feb. 18, 2020). And the unexpected difference must not just be matter of degree but a difference in kind. See Valeo North America, Inc. v. Schaeffler Tech. AG & Co. KG, IPR2016-00502, Paper 37 at 62 (PTAB June 20, 2017).

  1. Expert Declaration

The petition (as well as the patent owner’s response) should be accompanied by an expert declaration, offering supporting evidence and technical detail and explanation. See Xerox Corp. v. Bytemark, Inc., IPR2022-00624, Paper 9 at 15 (PTAB Aug. 24, 2022) (precedential). Avoid making conclusory and unsupported assertions. These add nothing to the petition, but instead may undermine your credibility. Id. Also, try to avoid repeating the petition’s content; instead, give the declaration some flavor by using charts, illustrations, and analogies. Have the experts prepare drafts of at least parts of their declarations. Doing so helps to ensure that the declaration does not look like a copy of the petition. Merely parroting the language of the petition without more may result in having the expert declaration deemed conclusory and dismissed as being entitled to little or no weight. See Xerox Corp. v. Bytemark, Inc., IPR2022-00624, Paper 12 at 5 (Director Review Feb. 10, 2023); Motorola Mobility LLC v. Maxell, Ltd., IPR2023-00110, Paper 7 at 34-35 (PTAB June 15, 2023).

Because there is no page limit for expert declarations, I have seen tendencies for expert declarations to be unduly long. You should avoid wordiness and redundancy in preparing expert declarations. Say what is necessary to establish your case without more. Remember the axiom that less is more. A long-winded expert declaration will water down your persuasive arguments and may come back to haunt you with unintended admissions and internal inconsistencies.

  1. Preliminary Response

Consideration should be given to whether the filing a preliminary response is in the patent owner’s strategic interest. Filing a preliminary response with detailed arguments on the merits of the challenged claims may prematurely show your hand and provide a roadmap for the petitioner to prepare its experts for their depositions. Remember that the element of surprise may be pivotal in getting admissions or concessions from your opponent’s experts.

It is important to note that the goal of the preliminary response is to persuade the PTAB to deny institution. Do what is necessary to achieve that objective, such as attack the petition on sufficiency or procedural grounds. These may include presenting arguments on discretionary denial, arguing that the petitioner failed to meet its burden or satisfy the necessary legal criteria, pouncing on claim limitations not adequately addressed in the petition, pointing out that the opponent’s expert opinions are conclusory, and seeking out any inconsistent positions. At this stage, making technical arguments without a supporting expert declaration is usually insufficient to tip the scale in your favor. Of course, each IPR petition presents its own unique challenges. There may be instances where a more detailed merit-based preliminary response is warranted.

  1. Depositions

In district court litigations, depositions are focused on gathering facts and preparing for impeachment at trial. Deposition testimony in an IPR, however, serves as actual trial testimony. Unlike district court litigations, there is no opportunity to cross examine the expert witness later at trial. The goal of depositions in an IPR is to confirm the opposing experts’ opinions to preclude them from changing positions in their reply declarations, expose inconsistencies or flaws, and seek admissions and concessions. You also want to avoid giving opposing experts opportunities to fill in gaps in their declarations.

  1. Patent Owner’s Response

Just as the petitioner, the patent owner needs to make arguments that are supported by the law, facts, and technical reasoning. You need to establish trust and credibility with the Board, and the best way to do so is to make well-supported and consistent arguments. Remember there is typically no live testimony before the PTAB, where the judges may be able to observe witnesses’ demeanor to assess credibility. Instead, the PTAB judges assess credibility based on the arguments you make on paper. Avoid making conclusory and inconsistent statements and weak arguments. Research patent owner’s other patents and publications in the pertinent field. I have seen situations where the patent owners made technical arguments that were contradicted by their own patents, damaging their credibility.

  1. Demonstrative Exhibits

At the oral hearing, you will have an opportunity to present demonstrative exhibits, which are typically provided to the PTAB judges days before the hearing. The judges will have reviewed your demonstratives before the hearing. Treat the demonstratives as another opportunity to tell a story as to why you should win. Your demonstrative exhibits should serve a roadmap for the PTAB judges to write a winning opinion for your client. You should focus on your key arguments, preferably with citations to any admissions or concessions you may have elicited from your opponent’s experts. Do not be afraid to use bullet points to explain your positions.

Stand Up to PTAB Scrutiny

In the intricate landscape of IPR proceedings, meticulous attention to detail and strategic thinking are key. This article highlights some practice tips for both challenging and defending patents before the PTAB. Presenting arguments supported by the law and technical reasoning, crafting effective expert declarations, conducting laser-focused depositions, and establishing trust with the Board are the cornerstones of success. By following these guidelines, practitioners can navigate IPR proceedings effectively, ensuring a compelling defense or challenge that stands the test of PTAB scrutiny.

*Special thanks to Justine Kawa, Venable 2023 summer associate, for her assistance in preparing this article.

Image Source: Deposit Photos
Author: gustavofrazao
Image ID: 84032870 


Warning & Disclaimer: The pages, articles and comments on do not constitute legal advice, nor do they create any attorney-client relationship. The articles published express the personal opinion and views of the author as of the time of publication and should not be attributed to the author’s employer, clients or the sponsors of

Join the Discussion

2 comments so far.

  • [Avatar for Pro Say]
    Pro Say
    October 26, 2023 04:16 pm

    Great advice Ben — thank you.

    That said, it really does boggle the mind that America — America for gosh sakes — actually runs a patent-killing . . . third-world-like . . . China-loving . . . alternative-universe adjudicatory process for innovation-key patents.

    Sick. Just plain sick.

  • [Avatar for Anon]
    October 25, 2023 03:03 pm

    Thank you for an excellent article.