Challenging and Defending Validity of U.S. Patent Claims before the Patent Trial and Appeal Board (PTAB) of the U.S. Patent and Trademark Office

As a result of the American Invents Act (AIA) signed into law on September 16, 2011, persons wishing to challenge the validity of claims in U.S. patents are now able to institute new inter partes actions in the U.S. Patent and Trademark Office (PTO), instead of resorting to much more costly litigation before a U.S. district court.

Although ex parte reexaminations and inter partes reexaminations have for some time been available as tools to challenge the validity of patent claims, these procedures were not viewed as favorable mechanisms. Ex parte reexamination procedures are still available today, although they have a major downside for the petitioner, as petitioners cannot participate in the proceeding once the reexamination is instituted. Inter partes reexamination was viewed as a more balanced approach, which allowed the requester and patent owner to participate in the reexamination process. Inter partes reexamination, however, did not provide for any discovery, so the hands of the parties were tied to challenge their opponent's proffered evidence.



Inter Parties Review(IPR) and Post Grant Review (PGR)

As of September 16, 2012, the AIA made available inter partes review (IPR), which replaces inter partes reexamination. The IPR procedure enables any person to contest the validity of patent claims using prior art patents and printed publications. This procedure is available for original patents and reissued patents filed under both the first-to-invent law and first-to-file law. For first-to-file patents, an IPR can only be filed after 9 months after the grant of the patent or the date of termination of a post grant review (PGR) of the patent. For first-to-invent patents, an IPR may be filed upon grant of the patent. PGR is anther validity challenge procedure available for first-to-file patents, if filed within 9 months of issuance. The PGR process can be used to challenge patent validity on an any statutory basis, not just prior art patents and publications. Those challenging the validity of patent claims typically will do so in response to allegations of patent infringement, an impasse in licensing negotiations or after a law suit has been filed. As a result, the decision to challenge the validity of an asserted patent claim will more often present itself well after nine months from the date the patent issued. For this reason, IPR challenges are the most common process being used by requesters.

A third party filing an IPR must meet a legal standard of proof. The legal standard of proof to successfully commence an IPR is a "reasonable likelihood" that the third party will prevail on at least one claim. In a PGR, on the other hand, the standard of proof is that at least one challenged claim is more likely than not to be considered unpatentable.

Although for first-to-invent patents an IPR can be filed at any time after a patent or reissue grants, those thinking of filing an IPR must consider the limitations presented by co-pending litigation involving the patent claims. For example, if the patent to be challenged is the subject of litigation, an IPR must be filed within one (1) year of the third party being served with a complaint involving the patent at issue. Additionally, a third party cannot file an IPR if that third party first files a declaratory judgment (i.e., civil action) challenging the validity of the patent claims. Further, those contemplating filing an IPR or a PGR should understand potential estoppel effects. That is, if a third party loses an IPR or PGR, the third party may be estopped from later raising the same validity grounds in court (or grounds that reasonable could have been raised).

Patent Strategy


Responding to Inter Partes Reviews (IPR)

PO receives an IPR

PO must file mandatory notice w/in 21 days of Petition filing

Is asserted art a patent or printed publication?

Is art valid prior art?

File continuations covering different subject matter and/or varying scope

Consider Reissue: broadening and/or Narrowing

Line-up expert evidence

Coordinate claim construction with or for litigation

PO Preliminary Response

Prioritize arguments

Identify technical defects in Request

Suggest elimination of duplicative grounds of rejection

Contest claim construction and suggest new construction

Identify inconsistencies in Petitioner positions

Determine if amendment will be needed if IPR is instituted

IPR is Instituted

Prepare PO Response

Board will provide preliminary opinion on claim construction

Prepare declarations:
(a) supporting claims, and (b) traversing Petitioner's experts

Arrange evidence, intrinsic and extrinsic supporting claim construction and traversing Petitioner's construction

Motion to Amend and substitute claims and depose Petitioner declarants

File PO Response timely

Petitioner Reply

Petitioner will take depositions of PO's experts, so experts should be selected accordingly

Petitioner will oppose PO's motion to amend

Consider updating claims in pending continuations and using Track One to expedite

Should reissue be filed?

PO Reply to Opposition
to Amend

Identify defects in Petitioner's logic

Ready to argue why amendment does not broaden

Ready to argue why PO has identified "all known prior art"

Preparing for Oral Hearing

Motions for observations

Motions to exclude evidence

File request for oral argument

Oral Hearing; present strongest points, no new arguments or evidence

Petitioner Strategy


What to file: IPR, PGR or CBM?

Considering an IPR?

Petitioner cannot have filed a
civil action to invalidate patent

Petitioner must file IPR within 1 year of being sued for infringement of patent

IPR is limited to challenge of a claim under 102 and 103, using patents and printed pubs

IPR available after 9 months of grant for first-to-file patents

IPR available immediately after grant for first-to-invent patents

PGR for first-to-file patents within 9 months of grant

IPR Filings

Petition must be no longer than 60 pages, excluding appendix
of exhibits, etc.

Filing cost: $9,000, up to 20 challenged claims

Institution Cost: $14,000, up to 15 challenged claims

Available for both first-to-invent and first-to-file patents

PGR/CBM Filings

Petition must be no longer than 80 pages, excluding appendix of exhibits, etc.

Filing cost: $12,000, up to 20 challenged claims

Institution Cost: $18,000, up to 15 challenged claims

Only available for first-to-file patents

PGR: Challenge claims under statutory sections 101, 102, 103 and 112

Expert Testimony

Petitioner may present expert testimony in the form of declarations

Declarations are filed as appendix in Petition and does not count toward page count

Use declarations to support claim construction, anticipation, and obviousness

Consider multiple experts

Claim Construction

Broadest reasonable interpretation standard, favorable to Petitioner

Support claim construction with expert testimony

Cite to specification, and prosecution history to support construction

Concurrent or Anticipated

Post grant counsel with USPTO experience is best suited to handle process before the Office

Litigation counsel and post grant counsel should define a unified plan early

Coordinate claim construction and arguments regularly

Post Grant Process


Post Grant Process

An instituted inter partes review (IPR) is litigation between the requestor and the patent owner in the PTO. As part of the patent reforms promulgated as part of the America Invents Act (AIA) of 2011, the PTO established the Patent Trial and Appeal Board (PTAB). The PTAB is staffed by administrative law judges (ALJs), who decide when requests satisfy the requisite standards to proceed, render decisions on motions, preside over oral arguments, and render final opinions on patentability. The trial procedure before the PTAB is different from the trial procedure in district court proceedings in that the trial procedure before the PTAB is limited to paper filings. Once each side has filed all of its documents during the various phases of the IPR, the ALJs will render an opinion. During the process, limited discovery is also allowed, which allows each side to challenge the substance of evidence presented and relied upon, which is most often declaration evidence.


The IPR process includes several stages, designed to expedite the overall process. In general, there are three stages in the process: (A) Petition Stage; (B) Institution and Discovery Stage; and (C) Hearing/Decision Stage.

PGR Timeline


A. Petition Stage

In the Petition Stage, a party wishing to challenge the validity of at least one claim in a U.S. patent may file a petition for inter partes review in the PTAB. The petition is a comprehensive document that outlines grounds for rejection of at least one claim based on one or more of prior art patents, prior art applications and printed publications. The petition should include a claims construction section, claim charts, exhibits and any declarations relied upon. The petition is served upon the patent owner upon filing, which starts the clock running for the patent owner's (PO's) Preliminary Response. This response is not mandatory, but it does represent the first instance where the PO can present reasons why the IPR should not be instituted. This response should include all the reasons why the Petitioner erred in applying the art, any reasons why the Petitioner has engaged in improper claims construction, any reasons why the alleged prior art is not actually prior art, and any other technical reasons why the IPR should not proceed. For a patent owner, the PO Preliminary Response should be viewed as mandatory, as a successful response may avoid the IPR all together or at least reduce the grounds upon which the IPR is instituted. The PO cannot file declarations in the PO Preliminary Response. However, patent owners should examine the substance of the Petitioner's declarations and start working with its own expert so that traversing declarations can be timely prepared if the IPR is instituted.

B. Institution and Discovery Stage

If the PTAB decides that the Petitioner has met his burden of showing that there exists a "reasonable likelihood of success" of establishing that at least one claim is invalid, then the IPR will be instituted. Ideally, the patent owner should be preparing during the Petition Stage, in case the IPR is instituted, as the timelines for discovery move quickly. If the IPR is instituted, the PO should be ready with an outline of its case and should be ready to depose the persons that authored declarations included in the Petition. Thus, by the time the IPR is instituted, the PO should have started to prepare its response, prepare experts to provide declarations, and determine whether or not to file a motion to amend the claims. In general, discovery is limited in IPRs, and the rule of thumb is that discovery is generally curtailed to deposition examination of declarants, and securing of documents that can be identified with particularity. If the party moving for additional discovery cannot identify the materials needed with particularity, then it is likely that such motions will be denied by the PTAB. If the PO decides that claim amendments are necessary, substantial work on the part of the PO will be required to prepare the motion to amend. The motion to amend must identify the support for the amendments in the original application or priority applications, must include an identification of the closest prior art known to the PO, and must set forth reasons why the claims remain patentable over all prior art, without exceeding a 15 page limit. As shown in the above timeline, the Petitioner will get an opportunity to reply to the PO Response and oppose the motion to amend. Additionally, because in most cases the PO will file declarations supporting its position, the Petitioner is provided the opportunity to depose the PO's declarants, during a three month Petitioner discovery period. After the Petitioner's discovery, the PO is provided with a final one month shorted discovery period. During this stage, the parties can request conference calls with the ALJ's assigned to the case, wherein disagreements can be discussed and ruled upon. At this point, the record should be complete from the standpoint of both the Petitioner and the PO, and the case moves to the next stage.

C. Hearing and Decision Stage

The parties can request an oral hearing by filing a separate paper that outlines the issues to be presented. Timing allotted for the hearing is set by an order granted in response to the request. Three ALJs are assigned to hear the oral arguments by the Petitioner and the PO. The oral hearing is the only opportunity the parties have to present their case in-person, however, the PTAB does caution that the oral hearing is not the place for parties to restate their entire case. Instead, parties are urged to focus on a few of their strongest positions in their case. Further, attorneys are urged to be familiar with the entire record, as ALJs will frequently interrupt to ask questions where they need clarification. As trial before the PTAB is tried based on the paper record, no live testimony is permitted in oral proceedings. Finally, no new evidence or arguments may be presented, and exhibits used during oral proceedings must be based on the record.


The PTAB decision may be appealed to the Federal Circuit. A civil action cannot be filed in district court. However, before appeal to the Federal Circuit is contemplated, the parties can file a request for rehearing within 30 days of the PTAB decision. The request for rehearing is limited, however, to issues that are believed to have been misapprehended or overlooked. Notice of Appeal to the Federal Circuit must be filed within 63 days of the PTAB decision or a rehearing decision.

PGP Questions


Post Grant Process Questions

The Post Grant Proceedings (PGP) group at MPG has an excellent track record of handling all types of reexamination proceedings. Attorneys working in the PGP group of MPG are seasoned practioners with decades of experience handling matters before the USPTO as well as handling litigation matters. Often, patent litigation is ongoing on the same patents involved in an IPR or PGR. MPG is a strong proponent of working closely and partnering with litigation firms, as systematic coordination is required so that consistent positions can be maintained throughout a post grant process. MPG's experience with post grant matters and small firm structure further translate into substantial cost savings that are passed on to the client.

If you have questions regarding post grant matters, we invite you to contact the firm. Chairs of the PGP group include Peter B. Martine and Albert S. Penilla.