Post Grant Review


Post Grant Review

Post grant review trials are heard before the U.S. Patent Trial and Appeal Board (PTAB) examining a patent’s validity. Post grant review is an opportunity for third parties to challenge the patentability of an invention without the time and expense of federal patent litigation. These trials are heard in front of a panel of three administrative law judges (ALJs) who are members of the PTAB. The procedure was created by the 2011 America Invents Act (AIA). It is designed for a swift timeline, with the entire process lasting 12 months, which can be extended for another six months for good cause.

In post grant review procedures, patent eligibility can be challenged under 35 USC §§ 101, 102, 103, and 112. Specifically, a petition can be filed under several grounds, including:

  • usefulness,
  • lack of patentable subject matter,
  • novelty,
  • obviousness,
  • indefiniteness,
  • written description,
  • lack of enablement,
  • anticipation,
  • public disclosures,
  • on-sale activities,
  • and public use.

The only grounds to challenge patent claim validity that cannot be raised through post grant review is “best mode,” which is a requirement that the inventor must disclose the best mode contemplated for carrying out the invention.

Despite this versatility of challenges available in post grant review proceedings, post grant review still has only limited availability. Specifically, third parties looking to challenge patentability via post grant review must initiate the procedure within nine months of the time the patent is granted. Once this nine-month window is expired, a third-party challenger may use inter partes review procedures, or may need to resort to challenging patent validity in federal patent litigationEx parte Reexamination is another option.

Post grant review proceedings can be instituted if a third party is facing a patent infringement lawsuit. If the patent claims are found to be invalid through post grant review in front of the PTAB, concurrent federal litigation may be dismissed. Thus, post grant review can be a useful tool for companies facing patent litigation claims.


The timeline for post grant review is the same as the timeline for inter partes review. However, they have different time frames of when the instigating petition can be filed. A post grant review trial can have the initiating petition filed as soon as a patent is granted, but it must be filed within nine months of the patent being issued or reissued. After nine months has elapsed, third parties may not raise post grant review claims. Instead, they must rely on inter partes review arguments to challenge patent validity.

Once the petition is filed, the patent owner has three months to file a preliminary response, but a response is not required. The PTAB then has another three months to decide whether or not a petition may move forward, otherwise known as instituting a trial. If the patent owner decides not to file a preliminary response, the timeline can be expedited to eliminate this three-month period.

From the time when the PTAB institutes the petition, all post grant review proceedings are expected to take 12 months. However, the Chief Administrative Patent Judge may, with good cause, extend a post grant review PTAB trial for an additional six months.

If the PTAB institutes a petition, the patent owner has a right to make a motion to amend the patent claims. The parties will also move forward with motion practice and discovery on a dual track, subject to a scheduling order. For the first three months, the patent owner will conduct discovery from the petitioner and must file a formal response. For the next three months, the petitioner may conduct discovery from the patent owner and must file its reply in support of the initial petition. Finally, the patent owner has one final month to conduct any outstanding discovery and file any remaining motions. The petitioner may file a motion to amend arguments raised in the original petition, while the patent owner may wish to amend its responses.

Discovery in post grant review trials typically consists of written documents, as well as testimony, including cross-examination, from expert witnesses. Either party may request additional discovery, which can be granted if they show good cause for their request. The parties may object to certain discovery requests or responses, and may also move to exclude certain evidence.

Either party may request an oral hearing after discovery is complete. At the oral hearing, each party is given one hour to dive between argument and rebuttal. Finally, the PTAB must enter a final written decision within one year of instituting the petition, unless the trial has been extended for an additional six months.

The final written decision may cancel some or all of the challenged patent claims, or it may leave the patent intact as issued.

From the time the petition is filed, a post grant trial can take 18 months to two years to complete. If the losing party decides to submit an appeal to the U.S. Court of Appeals for the Federal Circuit, this process can take longer. Once the time for an appeal has expired, or any appeals are terminated, the U.S. Patent Office will publish a certificate that:

  • Cancels any unpatentable claims,
  • Confirms any patentable claims, and
  • Incorporates any patentable, amended claims.


Any third party can file a post grant review petition challenging the validity of an existing patent, so long as:

  • The third party has not filed a civil action challenging the validity of the patent, and
  • The third party is not estopped from challenging the patent’s claims.

Post grant review petitions can be brought challenging:

  • Some business method patents,
  • Patents filed under the first-inventor-to-file system, and
  • Pending interferences.

If a patent was filed after March 16, 2013, and has no priority claims, the patent is considered first-inventor-to-file, and is eligible for these proceedings. First-to-invent patents are not eligible for these proceedings. As we move further away from March 2013, when the first-inventor-to-file regime was instituted, this eligibility question comes up less and less. However, if a patent does have a priority claim to an invention filed before March 2013 under the previous first-to-invent system, it may not be eligible for expedited proceedings.

Filed petitions must disclose any real parties in interest to the case as well as related judicial or administrative matters that may affect or be affected by the post grant review procedure.

Petitions cannot be filed if the petitioner or a real party in interest has already filed a declaratory judgment action challenging the validity of the patent’s claims. However, this prohibition does not come into play when validity challenges are raised as part of a counterclaim or affirmative defense in the face of a patent infringement case or during suits for declaratory judgment of non-infringement.

For a post grant review petition to be successfully initiated, it must meet a threshold showing that it is more likely than not that one or more claims will be found invalid. Post grant review challenges may be brought on a variety of grounds. The most common grounds are:

  • The challenged patent claims are obvious, arguing that a person having an ordinary skill in the art would be able to solve the problem the patent addresses by using the exact same mechanism.
  • The challenged patent claims are anticipated, meaning that they are too similar to a prior patent to be considered novel, and
  • The challenged patent claims consist of unpatentable subject matter, meaning that they are not a new and useful machine, manufacture, process, or composition of matter.

Successful petitions are specific in their arguments against patent claim validity, including detailed arguments and supporting arguments. The pleading standard for these petitions is generally higher than “notice pleading” required by federal courts.

Post Grant Review Statistics

Approximately half of filed petitions are instituted, meaning they go to trial. Some types of patents are more likely than others to have claims raised that merit a trial in front of the PTAB. Mechanical and business method, and electoral/computer patents are instituted 68% of the time, followed by chemical patents at 63% of the time, and bio/pharmaceutical patents 59% of the time. Only 40% of PTAB petitions based on design patents are instituted.

Differences Between Post Grant Review and Inter Partes Review

Although there are some similarities between post grant review and inter partes review trials, such as the timeline and general procedures, these are different procedures, with vital differences between the two types of actions. Inter partes review is significantly more popular than post grant review. Despite the general preference for inter partes review cases, post grant review trials often give filers more options to challenge patent validity. While inter partes review cases can only be brought on the basis of prior art or printed publications, parties challenging patent validity under post grant review can raise claims based on usefulness, subject matter, novelty, obviousness, lack of compliance with the written description, and public use. Post grant review and inter partes review are initiated on a different time schedule. For post grant review trials, a patent can be contested any time during the nine months after it was granted, while in inter partes review trials, the challenger must wait nine months or until any post grant review procedures have taken place.
The PTAB reviews all petitions and decides whether to initiate a trial. In post grant review proceedings, the petitioner must establish “that it is more likely than not that at least one of the claims challenged in the petition is unpatentable.” This is a higher standard than the inter partes review standard of “a reasonable likelihood that the petitioner will prevail with respect to at least one claim challenged in the petition.” A post grant review trial may also be instituted if the PTAB believes that the petition raises novel or unsettled legal questions that are important to other patents or applications.

Discovery in inter partes review procedures is more limited than in post grant review trials. Because post grant review trials typically cover more bases regarding patent validity, more documents will change hands. Moreover, in post grant review, the parties typically are generally allowed to seek additional discovery, which can drive up costs. In inter partes review trials on the other hand, the evidence is more limited because the issues are limited to questioning a patent’s validity based on prior art or previous publications. In inter partes review procedures, the PTAB is, in general, less likely to grant additional discovery. However, post grant review remains cheaper than traditional patent litigation in federal court.

Estoppel functions differently between the two procedures. First, estoppel created by inter partes review is applicable in later district court proceedings, but estoppel created by post grant review can come into play during later Patent Office proceedings, International Trade Center proceedings, as well as in front of the district court. Estoppel attaches in post grant review proceedings as soon as the PTAB issues its final written decision, but it only attaches in inter partes review proceedings after all appeals are exhausted.

In inter partes review proceedings, the third party bringing the challenging petition is estopped from relying on grounds that were raised or could have been raised in an earlier inter partes review proceedings, but in post grant review proceedings, the petitioner can only rely on grounds that were raised or could reasonably have been raised in earlier proceedings.

The fees for post grant proceedings are higher than those for inter partes review proceedings. To initiate a post grant proceeding with up to 20 claims, petitioners must pay a $16,000 fee. Each claim in excess of 20 claims are an additional $375. Once a petition has been instituted, there is an additional fee of $22,000 for up to 15 claims, with an additional fee of $825 for each claim in excess of 15.

The inter partes review fee, in comparison, is $15,500 to file a petition with up to 20 claims and $300 for each additional claim. Post-institution, there is an additional fee of $15,000 for up to 15 claims, and another $600 fee for each claim in excess of 15. Requests for oral hearings can cost between $325 and $1,300, depending on the size of the organization.

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