Patent Re-examination in Lieu of Litigation: Will They Work for Your Business
Written by David Bailey   
March 02, 2011

Los Angeles Daily Journal

Businesses are increasingly aware that patent reexaminations are a lower cost alternative to patent litigation. Less widely known is the fact that the likelihood of a patent being invalidated through reexamination is relatively low and that a poorly executed reexamination can actually strengthen a patent. The decision whether to put a patent into reexamination is best framed in terms of managing liability for patent infringement.

When executed correctly, the combination of a reexamination and a thoughtful redesign of an accused product can avoid liability for patent infringement entirely. Reexaminations are extremely effective at forcing patent owners to amend the claims of their patents, which can eliminate liability for past infringement. If the reexamination proves effective in invalidating the patent, then that is simply a bonus.

What is a reexamination?
A reexamination is a proceeding before the United States Patent Office (USPTO) in which a request is made for the USPTO to reconsider the validity of an issued patent. The reexamination process is similar to the original patent examination, with the exception that it is conducted by patent examiners that specialize in patent reexaminations.

There are two types of reexamination:
1) In an ex parte reexamination, the requestor does not participate in the reexamination of the patent. A benefit of ex parte reexamination is that the party requesting the reexamination can remain anonymous and is not prevented from revisiting the same challenges to the validity of the patent during litigation.
2) In an inter partes reexamination, the requestor can comment on the submissions made by the patent owner during the reexamination process. The party requesting the reexamination is required to identify themselves and is precluded from raising the same validity challenges during litigation.

How is a reexamination initiated?
In order to initiate a reexamination, the requestor must have prior art that calls into question the validity of a patent. The term “prior art” is typically used to refer to evidence concerning the state of the art prior to the filing date of a patent. Unlike litigation, the prior art that is considered is limited to printed publications. The reexamination is initiated by filing a request for reexamination with the USPTO that sets out in detail the reasons why the patent is invalid in view of the information contained within the prior art printed publications.

Claims can be challenged on the basis that they are anticipated by a specific piece of prior art, meaning that all of the elements of the claim are disclosed within the prior art reference. Claims can also be challenged on the basis that they are obvious, which typically involves relying on multiple pieces of prior art to demonstrate that all of the elements of the claim were present in the prior art and that it was obvious to have combined them.

The USPTO almost always grants requests for reexamination, even when the request for reexamination is based on prior art that has already been considered by the patent office. Therefore, the mere granting of a request should not be viewed as an indicator that the patent will ultimately be found invalid.

How successful are reexaminations?
Recent statistics published by the USPTO suggest that 13 percent of ex parte reexaminations requested by third parties are successful in invaliding the patent, and that claim amendments are made in an additional 63 percent of cases.

Inter partes reexaminations are more successful with 47 percent of patents invalidated and an additional 43 percent involving claim amendments. The increased likelihood of invalidating a patent through inter partes reexamination has resulted in an increase in their popularity. In the USPTO fiscal year 2010, 281 inter partes reexaminations were filed, with 100 filed between October 1 and December 31, 2010. This is compared with one inter partes reexamination filed in the USPTO fiscal year 2001.

How long does a reexamination take?
An ex parte reexamination typically takes around two years, whereas an inter partes reexamination typically takes about three years.

When will a reexamination eliminate past liability?
When the claims of a patent are substantively amended, all claims to damages for acts occurring before the issuance of a reexamination certificate are extinguished. For a claim to be substantively amended, the claim must be narrowed relative to the claims of the original patent. An amendment that simply incorporates the limitations of a dependent claim into an independent claim is unlikely to be considered a substantive amendment. The likelihood that a patent owner will be forced to make a substantive amendment is highly dependent upon the quality of the prior art submitted by the requestor.

When the requestor submits prior art that anticipates the relevant claims of the patent, the USPTO will typically force the patent owner to amend the claims to differentiate the claimed invention from the prior art. When the requestor submits prior art that renders the relevant claims obvious, the patent owner can overcome the rejections without amending the claims. In the event that the only prior art available renders the relevant claims obvious, then the additional cost of an inter partes reexamination is advisable so the requestor can respond to attempts by the patent owner to overcome the prior art without amending the claims.

Will litigation be stayed during a reexamination?
There is no guarantee that litigation will be stayed when a reexamination request is filed. The factors the court will consider include whether (1) the stay will prejudice the nonmoving party; (2) a stay will simplify the issues and trial of the case; and (3) discovery is complete and a trial date has been set.

The sooner the reexamination is filed the greater the likelihood that litigation will be stayed. If the patent office has already determined that a substantial question of patentability has been raised by the reexamination request, then the likelihood of a stay is increased. In addition, agreeing not to raise the same issues at trial in an ex parte reexamination can also increase the likelihood that a stay will be granted.

When can reexamination strengthen a patent?
Requesting reexamination provides the patent owner with an opportunity to strengthen the patent. The main way a patent can be strengthened during reexamination is that the patent owner can add additional claims, often targeting the accused product and drafted in light of the known prior art. The patent owner can also submit additional prior art.

Given that the patent is likely to emerge from reexamination, the patent that emerges will enjoy a presumption of validity over all the cited art and may include claims that are significantly harder to invalidate during litigation. Furthermore, the patent that emerges from reexamination may be perceived as having “survived” a validity challenge and a court or jury may be reluctant to invalidate the patent during subsequent litigation.

The best way to manage the risk that a patent will be strengthened through the reexamination process is to redesign the accused product during the pendency of the reexamination so that the redesigned product clearly does not infringe the patent.

When is a reexamination a bad idea?
Another danger of launching a reexamination is that the patent owner is provided with an opportunity to correct a flawed patent. Careful consideration should be given with respect to the filing of a reexamination where the patent in question is a business method patent or may have been procured through inequitable conduct.

The patent owner could use the reexamination as an opportunity to respond to the recent In re Bilski decision by adding limitations that increase the likelihood that the claims will be found to relate to statutory subject matter. Where the patent may have been procured through inequitable conduct related to a patent owner’s failure to cite relevant prior art, a reexamination may present an opening for the patent owner to cite the prior art minimizing the importance of its failure to do so in the past.

Overall, reexaminations can be an effective tool for managing liability for patent infringement. However, care should be taken to ensure that initiating a reexamination does not increase the likelihood that the patent owner will prevail during litigation.

David Bailey is a partner of KPPB, LLP an intellectual property law firm located in Irvine, California. David is one of the most highly sought after attorneys in the high technology sector due to his deep technical knowledge of digital signal processing and the online distribution of digital media. He can be reached at

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