Review proceedings for challenging the validity of an issued patent were established by The America Invents Act (AIA). These proceedings include Inter Partes Review (IPR), Post Grant Review (PGR), and the Transitional Program for Covered Business Method Patents (CBM). Such reviews operate as mini trials within the U.S. Patent and Trademark Office (PTO) between the third-party petitioner and patent owner. They are conducted before Administrative Patent Judges on the Patent Trial and Appeal Board (PTAB), who are well versed in both technical and legal aspects associated with determining a patent’s validity.

The proceedings typically take place within 18 months, from the date of filing a petition for review to the date of the final decision on the merits from the PTAB. The PTAB has the option of extending that time by an additional 6 months, if there is good cause. However, the PTAB has shown dedication in keeping on the tight schedule prescribed by statute. This includes an initial 3-month period for the patent owner to file a Preliminary Response to the petition for review, and then a further 3-month period from the filing date of the Preliminary Response (or expiration for the time for submitting the same) until the PTAB is required to issue a decision on whether or not to institute the proceeding. A decision to institute may be based on all or some of the grounds of rejection proposed by the third-party petitioner. Once instituted, the final decision on the merits should issue within 12 months. During that time, there will be depositions of the petitioner’s experts, a substantive filing by the patent owner in response to the instituted grounds, depositions of the patent owner’s experts used in that response, potential claim amendments, and a reply by the petitioner to the patent owner’s positions, among other filings. As compared to a district court trial, there is limited discovery, but either side may obtain additional discovery if it can show a well-reasoned need for the same. Provided below is the PTAB’s diagram of the general timeline for a review proceeding.

For a more detailed look at the schedule, view the schedule below:

Click here to view image.

In the right circumstances, IPRs, PGRs, and CBMs provide third-party petitioners with favorable, expeditious options for contesting the validity of issued patents before PTAB judges well versed in both patent law and technology. With the exception of CBM proceedings, petitioners can be any party, regardless of whether or not the entity has been sued by the patent owner or threatened with a suit for patent infringement (as long as the entity is not subject to estoppel). The details concerning estoppel and the differences between the options are provided in the links below.

The rules and procedures for the review proceedings borrow elements from the fields of inter partes reexamination and interference practice. For instance, the use of only patents and printed publications in IPR proceedings to challenge a patent’s validity is similar to that used in the prior inter partes reexaminations. While reexamination did not involve discovery, depositions, or motions, the rules for the same in IPRs are similar to the practices long used in interference proceedings before the PTAB.


As stated above, these proceeding take place before the judges of the PTAB.