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What is inter partes review or IPR?

An inter partes review or “IPR” is a relatively new legal mechanism to challenge issued patents. It was created in 2012 by the America Invents Act (“AIA”).

It is a trial procedure conducted at the Patent Trial & Appeal Board (“PTAB”) that challenges a patent.

Challengers in an IPR are limited in the types of challenges they may raise. Challenges must be for lack of novelty or obviousness under 35 U.S.C. §§ 102 or 103, and the challenges must be based on printed publications or patents. An inter partes review will be instituted upon showing that there’s a reasonable likelihood that a petitioner will prevail on at least one challenged patent claim.

Consequently, if you’re considering an IPR, you should also be heavily vested in patent searching and literature searching to identify challenging references. Experienced attorneys, who understand the litigation objectives, should perform these searches. Contact us here: to discuss this service or email us at

Why should we consider filing an IPR?

There are a variety of reasons to consider an IPR. The procedure is an incredibly important option to consider as part of a comprehensive litigation strategy. The IPR route may ultimately be cheaper than federal litigation and it may be used to pause federal litigation in some cases. Also, the Patent Trial & Appeal Board (“PTAB”) where the disputes are handled provides a unique forum, with experts in patent law who will evaluate the merits of the challenge.

Do you want to explain complicated validity issues to experts or do you want to explain to a jury? It’s an important question to consider in deciding whether an IPR should be filed.

Are there any downsides to filing an IPR?

The filing fees for inter partes review filings are not cheap, but when weighed against the price tag on federal litigation, it might look like a bargain.

The other issue with an IPR that must be considered is that it can create an estoppel (bar from raising the issue again) on many validity issues that might otherwise be raised later in federal court, the USPTO or the International Trade Commission. Final written decisions from IPR or PGR (post grant review) proceedings at the PTAB will bar relitigation of any ground raised or that reasonably could have been raised.

When should we consider filing an IPR?

If you have been threatened by a patent holder or sued by a patent plaintiff, you should consider filing an IPR, if the threat significantly concerns your business.

The challenger may request an Inter Partes Review either 9 months after a patent is granted, or after the termination of a Post Grant Review proceeding. In litigation, upon being served with a complaint for patent infringement, a defendant has one year to file a petition for inter partes review of a patent.

Challenges utilizing the IPR are limited to only statutory requirements of novelty and non-obviousness under 35 U.S.C. §§ 102 or 103. Challengers are also limited to only printed publications and patents for prior art purposes.

Is an inter partes review the same as a reexamination?

No, but they are both mechanisms to challenge a patent. The reexamination is much less expensive, but also does not have all the benefit of the challenger staying involved in the process.

With a reexamination, a challenger must raises a “substantial new question” of patentability. The procedure is filed ex parte, meaning that there is very little opportunity to participate once the challenge is launched.

A reexamination may be raised at any time during the time when a patent is enforceable. Like an IPR, it is limited to consideration of prior art patents or printed publications.

You might find interesting the following article which our firm wrote about the time of the introduction of the new IPR and other challenges: “The Landscape of Patent Challenges at the USPTO Post AIA.”

How does inter partes review relate to a case of patent infringement in federal court?

Sun Tsu’s Art of War went to great lengths discussing the importance of Terrain in battle, and the same could be said of considering the venue for a dispute in a patent infringement battle.

It is highly probable in federal patent litigation that there will be two fronts open—one at the patent office, and the other in federal court. In other circumstances, there may be fronts open at the International Trade Commission (“ITC”).

In some cases a federal court will yield to decisions from the PTAB, or “stay” a case pending an outcome in that forum. In other cases, a federal court will not pause or “stay” a case. Whether it does or doesn’t often depends on how far along a patent is in litigation, but the strategy of if and when to make challenges at the PTAB should be carefully considered.

Ideally, you need attorneys who are familiar with patent litigation in federal court and patent prosecution at the patent office. Our firm has experience in both of these departments. For a free initial consultation, contact us here: or email us at

Is an inter partes review expensive?

Yes, it will cost tens of thousands of dollars to initiate in PTAB fees, but they are paid in increments. Also, the price of initiating a PTAB proceeding will often pale in comparison to fees you will incur with unchecked federal litigation, particularly if waged by large law firms. For a detailed assessment of the likely costs of initiating an IPR, or other challenge proceedings, do not hesitate to contact us here: or email us at

What kinds of attorneys should handle inter partes review cases? Who should we contact for IPR evaluation?

You need to contact attorneys familiar with federal litigation, and who are also patent attorneys familiar with patent prosecution at the USPTO.

Do not hesitate to contact us here: or email us at

What should we do if an IPR has been filed against us?

Defend your patent rights if it covers a technology and revenues that your business cares about protecting. If an IPR has been instituted against you, chances are the rights are important enough to your adversary or competitor to have warranted the filing and legal fees, so a robust defense should be made.

You need to contact attorneys familiar with federal litigation, and who are also patent attorneys familiar with patent prosecution at the USPTO.

Do not hesitate to contact us here: or email us at