Surviving Inter Partes Review: Good Experts Are Key

Inter partes review and covered business method review (collectively IPR) proceedings have now settled in as a new strategic tool for invalidating asserted patents. The early cases that have worked through to a final written decision have resulted in a significant patent kill-rate. Still, some claims are surviving. The final written decisions in which patent claims survive show that, for a patent owner to succeed, it is critical to win the battle of the experts. The same conclusion holds true for those final written decisions that invalidate patents. This article addresses several observations common to many of these decisions regarding the use of experts.

1. Use an expert

Preliminarily, regardless of whether a party is challenging or defending a patent, a party is usually better served by employing an expert to help explain its case. An IPR is heard by a three-judge panel, and generally the judges have technical backgrounds. However, the assigned judges may not have technical backgrounds related to the patent at issue. The judges may have difficulty with terminology used in the art. Further, a judge may not recognize a difference of terminology used in the patent specification and claims, as opposed to the prior art. Accordingly, a patent owner should use an expert to ensure that it can provide an explanation of the art beyond what may be apparent from the prior art itself. If a patent owner does not use an expert, the panel will likely use the competing petitioner’s expert to bridge any knowledge gap. In those cases, the patent holder may lose simply because the differences between the prior art and the claimed invention are not clear to the panel.

Final written decisions, and many of the Board decisions that institute an IPR, show that the Board routinely considers the testimony of experts and credits one side’s expert, particularly regarding the content of the prior art. A Board decision denying inter partes review exemplifies the importance of using experts. In Monsanto Company v. Pioneer Hi-Bred International, Inc., IPR2013-00022, Paper No. 43 (PTAB Apr. 11, 2013), the challenged patent addressed a method of enhancing the quality of maize seed by defoliating maize plants after pollination. Monsanto submitted an expert declaration supporting its petition to institute review, arguing the claims were either anticipated or obvious by several references or combinations of references. The Board did not consider the testimony of Monsanto’s expert because the testimony was conclusory. Without the expert testimony, Monsanto was left with only the attorney’s argument. In ruling against Monsanto, the Board commented:

  • Absent Dr. Burris’ declaration, Monsanto has failed to identify sufficient credible evidence to establish that the prior art meets the GDD limitation of the claims. That is, the prior art references relied upon by Monsanto do not discuss the number of GDDs between pollination and defoliation. Therefore, absent Dr. Burris’ Declaration, Monsanto has not provided sufficient evidence to demonstrate that the prior art references anticipate or render obvious the limitation.
    Id. at 7.


In short, any petitioner or patent owner who does not submit expert testimony makes the Board more likely to find in favor of the opposing expert because of the lack of an alternative presentation. Considering the patent owner’s investment in acquiring the patent, as well as the petitioner’s work instituting review, going without expert testimony is penny wise, pound foolish

2. Build your expert’s credibility

Retaining an expert to help present the case is the first step. Once retained, counsel needs to build the expert into an authority figure on the subject matter. The short-cut employed by many practitioners is relying on the expert’s curriculum vitae. In all cases an expert’s curriculum vitae is submitted with an expert’s declaration of testimony to demonstrate that the expert is qualified to opinion on the subject. Parties should consider further developing the record to improve the persuasiveness of the expert beyond what is suggested by the expert’s curriculum vitae.

An example of a patent owner improving its expert’s persuasiveness is found in ABB Inc. v. Roy-G-Biv Corp., IPR2013-00062 & IPR2013-00282, Paper No. 84 (PTAB Apr. 11, 2014). In that case the patent owner succeeding in augmenting its expert’s credibility with deposition testimony derived from the petitioner’s own experts. The Board considered competing testimony from three Ph.D. experts in the same field, all of whom worked in the same laboratory at Carnegie Mellon University. In the final written decision, the Board summarized the opinion testimony of all three experts, noting:

  • On cross-examination, Dr. Voyles [(expert for petitioner)] admitted that Dr. Stewart [(expert for patent owner)] is an intelligent man and a reliable computer scientist. … Dr. Voyles also testified that he holds Dr. Stewart in high regard as a software engineer. … Dr. Papanikolopoulos [(second expert for petitioner)] testified he has submitted “multiple” letters of recommendation for Dr. Stewart. … Thus as described in detail below, we are not persuaded that Petitioner has established, by a preponderance of the evidence, that the combination of Gertz, Stewart, and Morrow renders claims 1-4 and 8-10 unpatentable under 35 U.S.C. § 103(a).


Id. at 22 (citations to the record omitted). In finding that the challenged patents were not unpatentable, the Board more easily credited patent owner’s expert given that petitioner’s expert conceded his credentials.

3. Ask the expert for detail, not just conclusions

The expert opinion should be crafted to specifically address the detail and basis for the opinions presented. A party who presents expert testimony consisting of conclusory statements, or to omit information (whether purposefully or not), risks a finding that the expert’s opinion deserves little weight. The regulations governing IPR warn “expert testimony that does not disclose the underlying facts or data on which the opinion is based is entitled to little or no weight.” See 37 C.F.R. § 42.65. Accordingly, an expert should explain and support the argument, not just provide conclusory statements regarding the state of the art, the existence of a limitation in the prior art, or why the prior art may teach away from the combination of prior art asserted.

The Monsanto and Roy-G-Biv decisions provide useful examples of how a lack of expert testimony may affect the case result. In Monsanto,patent challenger Monsanto purportedly offered expert testimony on whether the prior art disclosed the number of growing degree days for maize between pollination and defoliation, and why a person of ordinary skill in the art would have expected enhanced seed vigor in plants subject to defoliation. The Board rejected the testimony on this critical issue because the declaration lacked explanation of the underlying data supporting the expert’s conclusions. With the expert testimony eliminated, Monsanto could only rely on attorney argument and the prior art itself. Without more, the Board denied Monsanto’s petition to institute inter partes review.

Similarly, in Roy-G-Biv the petitioner lost in part because its expert testimony failed to provide supporting detail. A central issue in the cases was whether a person of ordinary skill in the art would consider “software code” and “downloaded configuration files” the same or different structures. The Board noted that one of petitioner’s experts did not directly address the issue in his declaration. Instead, the expert merely opined, “I feel it is far too restrictive to a person of ordinary skill to say there is a distinction between ‘software code’ and ‘downloaded configuration files’ in reference to that which Onika produces.” IPR2013-00062 & IPR2013-00282, Paper No. 84, at 20. The Board considered the expert’s testimony unpersuasive and conclusory.

Both decisions illustration the importance of having an expert address the who, what, where, when, and why surrounding the art and the invention in question. Absent this level of detail, the money spent on the expert will be wasted.

4. Keep the expert focused on points in contention

In mustering expert evidence to attack the challenged claims, line up testimony and argument to address each argument of the opposing side. Expert testimony will only win the day if it addresses disputed issues. Ensuring that there is expert testimony that covers each disputed issue can be overlooked. Roy-G-Biv provides a brief and potent example of what happens if expert testimony does not rebut opposing expert testimony. In that case, the petitioner only submitted opposition expert testimony to the expert testimony submitted by the patent owner. But when providing opposing expert testimony, the petitioner failed to address the patent owner’s arguments distinguishing that prior art. This oversight allowed the Board to make quick work of the arguments presented. The Board found that the petitioner failed to carry its burden and held that the challenged claims were not unpatentable.  

Nearly every IPR features expert testimony. Board decisions illustrate the importance of key practices:

  • Use an expert
  • Build your expert’s credibility
  • Ask experts to provide support for their conclusions
  • Make sure the expert addresses the relevant points in contention

With careful planning and attention to detail, you maximize the chances that the Board will be comfortable crediting your expert in its final written decision.

The articles on our Website include some of the publications and papers authored by our attorneys, both before and after they joined our firm. The content of these articles should not be taken as legal advice.