patent-qualityAmong the many changes to the U.S. patent system wrought by the America Invents Act of 2011 was the introduction of review options that become available to third parties after a patent is granted.

Post-grant review and inter partes review (IPR) both provide interested third parties with a relatively quick and inexpensive alternative to challenging a patent through civil litigation. Any application filed with the USPTO under the “first to file” standard on or after March 16, 2013, is eligible for post-grant review. Inter partes review, which replaced the former inter partes reexamination procedure on Sept. 16, 2012, can be instituted against any currently enforced patent, provided certain conditions are met.

Unlike IPR, which becomes available after the issued patent is nine months old, post-grant review allows a third-party petitioner to challenge an issued patent on virtually any grounds.

“Best Mode” Requirement

An important exception to the potential grounds for post-grant review is the “best mode requirement.” Section 112 of the U.S. Patent Act requires that an inventor disclose “the best mode” for carrying out the invention specified in the application. In the past, third parties could (and often did) take legal action against patent holders with the claim that the patent failed to disclose the best mode, i.e., that the disclosure described a watered-down version of the invention and allowed the patent holder to hide the “real” invention.

With the passage of the America Invents Act, the Section 112 requirement that an inventor disclose “the best mode” for carrying out the specified invention can no longer be used as a basis for invalidating a patent once it has been granted. Patent examiners are still instructed to evaluate whether an inventor has disclosed the best mode in the patent application, but the examiner’s findings in this regard are, in effect, no longer open to second guessing from third parties. This includes post-grant review.

Other Arguments

Aside from “failure to disclose best mode” arguments, however, a post-grant review petitioner may cite any grounds raised by the examiner or, crucially, any grounds that “reasonably could have been raised” as a basis for invalidating the patent or any of its claims.

The petitioner is required to identify each claim of the patent that it is challenging, cite the relevant grounds for each individual claim challenged and provide some kind of evidence supporting each of the challenges. As daunting as that may sound, the standard for demonstrating that an invention is unpatentable is lower in post-grant review than it is during civil litigation. A civil plaintiff must provide “clear and convincing evidence” that an invention is unpatentable. A post-grant review petitioner, by comparison, need demonstrate only “a preponderance of the evidence.”


The patent holder has three months to submit an optional, preliminary response to a post-grant review petition. The preliminary response is typically an argument against the validity of the petition. When the preliminary response is received by the USPTO, or when the deadline to file a response passes, the USPTO then has an additional three months to decide whether to initiate a review.

If post-grant review begins, it will be heard by the Patent Trial and Appeal Board (PTAB). Like all PTAB proceedings, the arguments on each side of a post-grant review are heard by a three-member panel of administrative patent judges, each of whom has equal weight in determining the outcome of the hearing. Administrative patent judges are generally very experienced intellectual property professionals and usually have a deep background in one or more technology fields. Their expertise distinguishes them from the more generalized legal background of the judges who typically hear patent cases in civil litigation.

Among the most crucial ways in which post-grant review is distinguished from civil litigation proceedings is the limited scope of the discovery phase. Post-grant review discovery is limited to factual assertions made by either the petitioner or the patent holder during the course of the review process. This differs also from inter partes review, which permits the deposition of witnesses and allows for outside parties to submit briefs or affidavits in support of either party’s contentions. As with a civil court proceeding, the petitioner and the patent holder are free to reach a settlement outside the confines of the review process.

As with any matters heard by the PTAB, either party in the hearing can appeal the outcome to the Federal Circuit of the U.S. Court of Appeals.