Using the PTAB as part of a successful defensive strategy

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Approximately 85% of patents challenged in a post-grant review proceeding at the USPTO PTAB are involved in co-pending litigation. With litigation potentially occurring across more than one forum – the PTAB, a US district court or the US International Trade Commission (ITC) – often in parallel, the value of a PTAB trial, pending or instituted, cannot be understated.

Stay of litigation

The America Invents Act created new post-grant review proceedings – inter partes review and post-grant review – to replace the older inter partes re-examination procedures. The America Invents Act proceedings are intended to “create a timely, cost-effective alternative to litigation”. The concurrent nature of the act’s proceedings provides a strategic advantage but may also increase the total cost of the overall litigation to the parties.

Seeking a stay of litigation outside the PTAB is one approach to streamline the litigation and control costs. A court weighing a motion to stay litigation pending resolution of a PTAB trial will normally consider:

  • the status of the case, including whether it is close to trial;
  • whether a stay will simplify the issues before the court; and
  • whether a stay would unduly prejudice or disadvantage the plaintiff (or patent owner).

The analysis, however, is not limited to these factors and must be based on “the totality of the circumstances”.

The decision on when to file a motion to stay is important, given the competing case schedules at the PTAB and other forums. On the one hand, a defendant PTAB petitioner may want to move to stay as soon as practicable to maximise the reduction in the cost of litigation. Waiting too long to seek a stay may also lead to the court denying the request altogether. On the other hand, moving for a stay prematurely (ie, before a PTAB trial is instituted) is generally less likely to be successful.

The timing of a stay motion is also important because it may affect what substantive issues are considered by the district court and how the court’s decisions may interact with the PTAB case. For example, a claim construction order by the district court will likely affect the pending PTAB case, and vice versa. If the district court order comes out before a PTAB trial is instituted, the PTAB may, by operation of its discretion, elect not to institute the trial in the first place. Even if the trial is instituted, the PTAB may consider the district court’s claim construction order and may change its own view of the validity challenge.

The most advisable course of action for a defendant PTAB petitioner who wishes to stay a related co-pending case in a district court is to move quickly to file a PTAB challenge. Filing early is likely to give a party the highest chance of success in securing a stay. Filing a request for a PTAB trial early, of course, raises another concern: which claims should be challenged at the PTAB to further increase the likelihood of a stay? A plaintiff PTAB patent owner does not generally need to disclose asserted claims until several months into a district court case. This requires the defendant PTAB petitioner to decide whether to challenge all claims of the patent or a subset of those claims. Filing a PTAB challenge early, however, may help to address this concern, at least in part. A defendant PTAB petitioner that challenges only a subset of the patent’s claims has good arguments for later filing additional challenges. Covering less than all asserted claims, however, may have an impact on the success of a stay motion filed in the district court. As a result, the timing of a request for a PTAB trial and the filing of a stay motion become key considerations.

Litigation position preview

A PTAB challenge may allow parties to get an early preview into the other side’s district court case. But before a preview can be secured, the parties will often engage in a dance to establish that an instituted PTAB trial is an efficient use of the parties’ and the PTAB’s finite resources. In Apple Inc v Fintiv Inc (IPR2020-00019, Paper 11, 20 March 2020), the PTAB concluded that not all requests for a PTAB trial should be granted because doing so would be inefficient. This inefficiency is made clear where, for example, a related co-pending district court case will go to trial before the PTAB is expected to finally resolve its case and the district court trial will address the same validity issues pending before the PTAB.

To combat this potential for inefficiency, the PTAB has enumerated six factors that it considers when deciding whether to institute a PTAB trial:

  • whether the district court granted a stay or evidence exists that one may be granted if a proceeding is instituted;
  • the proximity of the court’s trial date to the PTAB’s projected statutory deadline for a final written decision;
  • the investment in the parallel proceeding by the court and the parties;
  • overlap between issues raised in the petition and in the parallel proceeding;
  • whether the petitioner and the defendant in the parallel proceeding are the same party; and
  • other circumstances that affect the PTAB’s exercise of discretion, including the merits.

The PTAB analyses these factors on a sliding scale and takes a holistic view of the specific circumstances of each case. While the PTAB’s application of these factors has been criticised recently, parties seeking a PTAB trial must address them.

Efficiency aside, a request for a PTAB trial requires the defendant PTAB petitioner to identify its prior art, which claims it is challenging, any claim constructions that it deems important and a disclosure of the full set of evidence that will support the challenge. The request is the defendant PTAB petitioner’s case in chief and should be as complete as possible. A defendant PTAB petitioner cannot hold back its best arguments and disclose them later ‘when the time is right’.

This requirement for full disclosure usually quickly highlights to the plaintiff PTAB patent owner what prior art the defendant PTAB petitioner considers to be the strongest. The plaintiff PTAB patent owner can then better formulate its litigation strategy across multiple forums.

The request for a PTAB trial, then, has the further potential to disclose to the plaintiff PTAB patent owner what claims the defendant PTAB petitioner is most concerned about. If a defendant PTAB petitioner challenges fewer than all claims of a patent, and files its challenge before the plaintiff PTAB patent owner identifies its asserted claims in the district court, the plaintiff PTAB patent owner can glean what claims the defendant PTAB petitioner is most concerned about. This presents the plaintiff PTAB patent owner with an option to better construct its case in the district court or assert additional claims that are not being challenged. While the former can help streamline the case, the latter may cause the district court to deny a pending stay motion and negate or neutralise any benefit that a defendant PTAB petitioner can gain through filing itsrequest.

After the defendant PTAB petitioner files its request, the plaintiff PTAB patent owner may file a preliminary response. This brief is intended to identify reasons why the PTAB should not institute a trial on the request. An important factor turns out to be claim construction. A defendant PTAB petitioner may not request the PTAB to construe any terms recited in the challenged claims or may propose constructions for specific terms. The constructions may be proposed because they are necessary to map the asserted prior art to the claims or the defendant PTAB petitioner may, for example, be seeking statements about claim construction from the plaintiff PTAB patent owner or the PTAB that it can use in the district court litigation. A plaintiff PTAB patent owner can either respond to the proposed constructions or propose constructions of its own, which may potentially create a basis for the PTAB to deny review altogether. In either case, the request and preliminary response usually highlight early a disputed issue, one that likely would not become apparent in district court litigation until the case was fairly well developed later in the proceeding.

Improve settlement position

Filing a request for a PTAB trial usually crystalises issues in dispute between a patent owner and an accused infringer. As a result, it also helps resolve the dispute itself. If the PTAB finds that the challenged claims are unpatentable, the underlying dispute relating to the claims will become moot, assuming it is upheld on any appeal. This is a big positive for a defendant PTAB petitioner, especially in view of the significantly lower cost of a PTAB trial.

The existence of a request for a PTAB trial can add leverage. If a PTAB trial is not instituted, the plaintiff PTAB patent owner has gained leverage in the overall dispute because it can argue that the defendant PTAB petitioner’s case is weak and has been rejected by the very entity that issued the patent in the first place. While it is possible that the PTAB’s decision not to institute a trial will be kept from a district court jury in limine, it can still affect the overall case. If, on the other hand, a PTAB trial is instituted, the defendant PTAB petitioner’s case is strengthened and its settlement position has been improved. Of course, there are no guarantees that an instituted PTAB trial will result in claim cancellation, but the institution adds additional risk to the calculus of the case.


Validity challenges at the PTAB are now a key component of most patent infringement disputes. The forum does not inherently favour any one party and, as a result, it affords the possibility of leverage by either party to improve their litigation position overall.

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