Inter partes review (IPR) was introduced by the America Invents Act (AIA) as a counterpart to post-grant review. Together, they collectively replace inter partes reexamination with inter partes review, becoming available only after the period for post-grant review has passed.
The USPTO released the final rules for inter partes review, the trial practice guide, and the general administrative trial final rules on August 14, 2012:
Final Rules for Inter Partes Review
Final Rules for Trials before the Patent Trial and Appeal Board
Practice Guide for Final Trial Rules
Technical Corrections to the Leahy-Smith America Invents Act as to Inter Partes Review
Fish & Richardson’s IPR Snapshot Guide
Inter partes review became available on September 16, 2012, as a procedure to challenge the validity of patent claims based on patents and printed publications. Inter partes review can be initiated immediately following issuance (or reissuance) of patents examined under the first to invent rules (i.e., patents filed prior to March 16, 2013), since post-grant review is not available for these patents. For patents examined under the AIA first to file rules (i.e., patents filed on or after March 16, 2013), inter partes review can be initiated after the nine-month window of eligibility for post-grant review. In other words, for patents that were filed on or after March 16, 2013, post-grant review is the mechanism for challenging the validity during the nine-month window immediately following patent issuance while inter partes review is the mechanism for challenging the validity after the nine-month window.
Inter partes review is similar to post-grant review, but there are several significant differences between the two proceedings, described below.
1. Inter partes review became available for all patents on September 16, 2012, regardless of priority date.
2. Inter partes review is subject to an additional limitation relating to co-pending litigation involving the patent being reviewed. Both post-grant review and inter partes review need to be filed before the third party seeks a declaratory judgment challenging the validity of a claim in the patent. In addition, an inter partes review must be filed within one year of the third party being served with an infringement complaint by the patentee.
3. The standard of proof required to justify commencement of an inter partes review is also slightly different than the standard of proof required to trigger commencement of post-grant review. For an inter partes review to be commenced, a third party must establish a reasonable likelihood that they will prevail on at least one claim, as opposed to post-grant review’s requirement that at least one challenged claim is more likely than not to be deemed unpatentable. The AIA fails to specifically address this difference in standards, leading to widely varying speculation about whether there will be a significant difference in the way a request under inter partes review is treated relative to post-grant review.
4. The prior art available for inter partes review is limited relative to post-grant review. Inter partes review is akin to inter partes reexamination in that it is limited to prior art grounds based on patents and printed publications, whereas post-grant review can be based on any grounds that are available for an invalidity defense. Significantly, this constraint limits the estoppel effects of inter partes review relative to post-grant review. Post-grant review may preclude a third party from raising virtually any invalidity defense in litigation. The scope of legal estoppel for inter partes review is commensurate with current inter partes reexamination estoppel. Thus, even if it has availed itself of inter partes review, a third party should retain their ability to raise invalidity defenses in other fora based on all grounds other than patents and printed publications that were or reasonably could have been raised during the inter partes review.
The procedural schedule for IPR is included below: