A significant difference in the new inter partes review (IPR) proceedings versus the previous inter partes and ex parte reexamination proceedings is the availability of discovery to both petitioners and patent owners in IPR proceedings. Although the America Invents Act provides for various categories of discovery, the scope of discovery in IPR proceedings is significantly less than what is typically allowed in district court litigation.

In particular, parties to an IPR may pursue additional discovery beyond certain, predefined categories only upon a showing that the requested discovery is “necessary in the interest of justice.”1 Recent decisions by the Patent Trial and Appeal Board (PTAB) confirm that such discovery will not be granted as a matter of course, and even when available, will be relatively restricted in scope. Indeed, many motions for additional discovery have been filed, but the PTAB has allowed additional discovery in only three decisions thus far. As case law continues to develop in this area, parties involved in IPR proceedings must carefully consider how to draft appropriate requests for discovery, and when challenged, demonstrate the materiality of those requests to the PTAB.

Categories of Discovery Available in Inter Partes Review

The America Invents Act limits discovery in IPRs to “the deposition of witnesses submitting affidavits or declarations” and “what is otherwise necessary in the interest of justice.”2 The U.S. Patent and Trademark Office, however, has further interpreted these provisions to cover “routine discovery” and “additional discovery.”3

Routine discovery generally refers to three categories of discovery that will always be available to a party in an IPR: (1) exhibits that are cited in filings or affidavits, (2) cross examination of individuals submitting affidavit testimony, and (3) relevant information that is inconsistent with a position being advanced by the other party.4

Additional discovery refers to any other discovery a party wishes to pursue. Although the subject matter of such requests is not explicitly restricted, if the parties cannot agree on the availability or scope of additional discovery, the PTAB will allow it only upon a showing that “such additional discovery is in the interests of justice.”5 As will be explored in greater detail below, “the interest of justice” standard has been rigorously enforced by the PTAB, and additional discovery is rarely granted.

Even when additional discovery is allowed, the requests must be narrowly tailored and the scope restricted.6 The PTAB’s guiding principle in deciding requests for additional discovery, oft repeated, is that “[g]iven the statutory deadlines imposed by Congress and with the limited nature of additional discovery in inter partes review proceedings, the Board will be conservative in authorizing additional discovery.”7 Further, “[a]s Congress intended inter partesreview to be a quick and cost effective alternative to litigation, discovery in aninter partes review is less than what is normally available in district court patent litigation.”8

Factors Impacting Whether Additional Discovery Is in The Interests of Justice

The PTAB first articulated a test for determining whether a discovery request is “in the interest of justice” in Garmin v. Cuozzo, in which the PTAB identified five factors that as being important to such an evaluation:

  1. More Than A Possibility And Mere Allegation -- The mere possibility of finding something useful, and mere allegation that something useful will be found, are insufficient to demonstrate that the requested discovery is necessary in the interest of justice. The party requesting discovery should already be in possession of evidence tending to show beyond speculation that in fact something useful will be uncovered.
  2. Litigation Positions And Underlying Basis -- Asking for the other party’s litigation positions and the underlying basis for those positions is not necessary in the interest of justice. The Board has established rules for the presentation of arguments and evidence. There is a proper time and place for each party to make its presentation. A party may not attempt to alter the Board’s trial procedures under the pretext of discovery.
  3. Ability To Generate Equivalent Information By Other Means – Information a party can reasonably figure out or assemble without a discovery request would not be in the interest of justice to have produced by the other party. In that connection, the Board would want to know the ability of the requesting party to generate the requested information without need of discovery.
  4. Easily Understandable Instructions -- The questions should be easily understandable. For example, ten pages of complex instructions for answering questions is prima facie unclear. Such instructions are counter-productive and tend to undermine the responder’s ability to answer efficiently, accurately, and confidently.
  5. Requests Not Overly Burdensome To Answer -- The requests must not be overly burdensome to answer, given the expedited nature of Inter Partes Review. The burden includes financial burden, burden on human resources, and burden on meeting the time schedule of Inter Partes Review. Requests should be sensible and responsibly tailored according to a genuine need.9

It is not entirely clear how the PTAB weighs individual factors or if any single factor can be determinative in deciding whether additional discovery is in the interest of justice. At least with respect to Factor 1, however, several decisions suggest that its dual requirements may act as a threshold requirement for further consideration.

To that end, the requesting party must both (1) possess evidence tending to show that the requested discovery will lead to further evidence and (2) demonstrate how that further evidence will materially impact its position(s) in the IPR proceedings.10 The first requirement comes directly from the language of Factor 1, and the second relates to the requirement that “something useful” will be discovered. “In the context of Factor (1), ‘useful’ means favorable in substantive value to a contention of the party moving for discovery.”11

Similarly, the PTAB has refused to address whether poorly drafted or badly argued discovery requests would otherwise be allowed. In order to be considered, discovery requests must be clearly articulated and specifically drawn.12 And when moving for additional discovery, the requesting party “must explain with specificity the discovery requested and why each item requested is necessary.”13 Absent such explanation, the request will be denied without further consideration.

It has been more than a year since the PTAB provided its guidance regarding requests for additional discovery in Garmin, and although several motions have been decided in the interim, the PTAB has allowed additional discovery only three times.14 It is therefore instructive to examine the PTAB’s analysis in those decisions when considering future requests for additional discovery in IPR proceedings.

Successful Motions for Additional Discovery

The PTAB first allowed additional discovery in connection with an IPR instituted by Corning Inc. in which Corning alleged that certain compositions were unpatentable over the prior art based on inherent properties of prior art compositions.15 In support of its position, Corning prepared compositions according to the teachings of the prior art and tested them; and DSM IP Assets, the patent owner, sought discovery related to the creation of the compositions. Interestingly, the PTAB determined that laboratory notebooks describing the manufacture were not “routine discovery” because the PTAB “d[id] not agree that any reference to experiments in a paper requires that all the underlying data and lab notebooks be produced with the paper.”16Regardless, the PTAB determined that DSM made adequate showings under Factor 1 of the Garmin test because the laboratory notebooks clearly existed and because the patent owner pointed to specific missing evidence related to the creation of the compositions that impacted whether or not the compositions had truly been prepared according to the teachings of the prior art. The otherGarmin factors were all neutral, so the PTAB allowed discovery of the laboratory notebooks.17

Reiterating the strict standard for additional discovery, however, the PTAB denied DSM’s additional requests for actual samples of the compositions and evidence of test results that were inconsistent with Corning’s inherency argument.18 The request for samples was denied at least in part because it was deemed overly broad in that DSM’s motion for additional discovery alleged only that some, not necessarily all, of the samples would be difficult for DSM to manufacture.19 And DSM’s request for inconsistent test results was denied on the theory that such evidence, if it existed, should have been produced in connection with “routine discovery.”20

In the second decision in which the PTAB allowed additional discovery, Apple was successful because it sought very limited discovery and because it waited to move for additional discovery until after securing evidence that the sought-after discovery existed and directly impacted positions adopted by the patent owner in the IPR.21 Apple sought discovery only of specific emails that had been identified in deposition testimony as pertaining to and helping to form the basis of opinions expressed by the patent owner’s expert witnesses (who had been communicating directly with one another in said emails).22 The PTAB found that “the factual basis for a declarant’s opinions is a proper inquiry during discovery” and therefore ordered the emails produced.23

Finally, on April 23, 2014, the PTAB granted in part a request for additional discovery by the patent owner in an IPR proceeding involving Atlanta Gas Light Co. and Bennett Regulator Guards.24 Once again, the PTAB’s analysis focused largely on Factor 1 of the Garmin test. The PTAB allowed additional limited discovery as to the real parties-in-interest based on a specific indemnity dispute referenced in a sworn affidavit, but only as to documents and things concerning “[t]he character of the dispute and any resolution of or failure to resolve the dispute.”25 Additionally, the PTAB refused to allow discovery seeking evidence of possible explanations for or implications of the dispute, because according to the PTAB, “such inferential allegations amount to a ‘mere possibility of finding something useful, and mere allegation that something useful will be found,’” and therefore do not satisfy Factor 1.26


The PTAB’s treatment of motions for additional discovery continues to evolve, but it is clear that such requests must be limited in scope in order to succeed. Parties should draft their discovery requests clearly and narrowly. And while parties should pay attention to all five Garmin factors when moving for additional discovery, satisfying Factor 1 appears to be a threshold issue. Therefore, parties must demonstrate not only that the sought-after information likely exists, but also that it materially affects their position(s) in the IPR.