Patents are presumed valid under the law, but there are circumstances when questioning patent validity might become important. If this happens, there are two formal legal procedures through the United States Patent and Trademark Office (USPTO) available to question the validity of the claims of an issued patent. The two procedures are: 1) ex parte reexamination, and 2) inter partes reexamination. If you have reason to question the validity of the claims of a patent and your evidence (prior art) is proper (available before the patent application), you can get the claims of a patent un-patented.

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When and How to Question Patent Validity

Any person or business is permitted to write and file either a petition for an ex parte reexamination or a petition for an inter partes reexamination. If you or your business are accused of infringing on an enforceable patent, you might want to question the validity of that patent. If you already make a product, device, or software application that was patented by someone else after you were making, using, and/or selling it, you may want to question the validity of their patent. The validity of the claims of a patent can be questioned using either the ex parte reexamination or the inter partes reexamination procedures through the USPTO.

Invalidating a Patent’s Claims with Ex Parte Reexamination

The most common method to question patent validity is a petition for an ex parte reexamination. Once a patent is issued, it is legally presumed valid because the United States Patent Office (USPTO) has approved its patentability by issuing a patent. However, if a person or another business wishes to challenge the patentability of the claims of an already issued patent, they have the right to.

An ex parte reexamination is a petition to request the USPTO to reexamine an already issued patent. This is a method of reevaluating a patent’s validity outside of the patent litigation processes. Available since 1981, this method of patent validity remains available under the America Invents Act (AIA). An ex parte reexamination can be initiated by the patent owner or a third party. However, unlike the inter partes reexamination, once the ex parte reexamination is filed, if the requester is a third party, they are excluded from the reexamination process until the final decision is concluded. The patent owner can respond by submitting a statement of their patent validity assertions for all claims questioned. 

An ex parte reexamination can occur at any point after a patent has been issued to question patent validity by raising a substantial new question of patentability for any or all claims of the patent. The requester must provide all necessary evidence that any questioned claim is either not novel or is obvious based on prior art published prior to the date that the patent application for the issued patent was filed. Such prior art must be from publications, previous patents, or previous patent applications. Most importantly, the prior art must establish a substantial and new question of patentability for each claim questioned.

Important Tip: The proof (prior art) must have been published prior to a patent’s effective filing date in order to be considered valid. 

If the petition for reexamination is granted, the reexamining (patent validity analysis) process begins. A specialized unit of the USPTO, called the Central Reexamination Unit (CRU), is made up of three experienced patent examiners that will review the provided substantial new question of patentability for each claim questioned. It is up to the CRU to make a decision to uphold a patent’s validity or to overturn it. Note that, requests for continued examination (RCEs) are not available for this method of questioning patent validity. 

Ex Parte Reexamination Petition Timeline

The USPTO aims to complete an ex parte reexamination within two years of granting a reexamination petition. In the first three months after an ex parte reexamination request is filed, the CRU must make a decision on whether they will grant or reject the petition. If rejected, the requester has up to one month to petition for reconsideration of the reexamination request petition. If granted, the owner of the challenged patent has up to two months to file a statement.

The patent owner’s statement is a response to the ex parte reexamination request and counters the questions of patentability raised in the reexamination request. This statement is not mandatory to file, but it is usually submitted. If a patent owner does file a statement, the requester of the ex parte reexamination has another two months to to reply to the statement. This response is also not mandatory to file, but it is usually submitted.

Following the CRU’s decision to grant or deny a reexamination and after the patent owner’s statement and requester’s response, the CRU will docket the case and conduct a review on the merits and a first office action is issued. If any claims are found invalid, it is the responsibility of the patent owner to reply to the first office action within two months. Additionally, the patent owner has the right to request an interview of the CRU members.

Within about two months of receiving the patent owner’s reply to the first office action, the CRU will again conduct a review and examination of all the issues and send out a second office action. This second office action is intended to be the CRU’s final decision on the reexamination proceedings. If there is an invalidation of any claims, a patent owner has a period of two months to file an after-final response. If submitted, it is not mandatory for the response to be filed by the CRU. However, if the CRU does decide to file a response, the requester will be given a time period of one month to submit a response.

A final decision leaves the challenged patent owner limited options. A final rejection means the patent owner no longer has a right to further prosecute. A patent owner can overcome the rejection by filing a notice of appeal or an after-final reply that accepts allowable subject matter or proposes narrowing amendments for allowability.

If the after-final response fails to place all claims in a condition where they are patentable, the CRU will issue an advisory action to the patent owner. This advisory action allows the patent owner time to consider the action and either file a notice of appeal or a second response that places all claims in a condition where they are allowable.

The CRU has the option to refuse changing their mind after viewing an after-final response. This means the challenged patent owner would have to appeal to the USPTO Patent Trials and Appeals Board or in federal appeals court. Once the ex parte reexamination proceedings are concluded, the CRU will issue a Notice of Intent to Issue Ex Parte Reexamination Certificate (NIRC). This NIRC displays the status for each claim that was made.

Ex parte reexamination should be considered with caution. It is an expensive petition to research and write costing $5,000 – $25,000 in patent attorney fees. Further, the government filing fee is nearly $13,000.

If a reason to file an ex parte reexamination arrises within the first nine months of the issuance of a patent, there is also the inter partes reexamination petition procedure to question the validity of the claims of the issued patent.

Invalidating a Patent’s Claims with Inter Partes Reexamination

An inter partes reexamination is another form of invalidating the claims of an issued patent when questioning patent validity. Inter partes reexaminations allows a third party (the requester) the right to participate in the reexamination process. The requester of the reexamination must provide reasonable proof (evidence) that one or more claims of the challenged patent can be invalidated. However, as with ex parte reexamination, the only prior art allowed to be considered during reexamination is prior patents, patent applications, or printed publications. Note that inter partes reexaminations do not permit the scope of patent claims to be broadened by amendment during the proceeding.

Although both question patent validity, there are some differences between an inter partes reexamination and an ex parte reexamination. One key difference has to do with who facilitates the reexamination of a patent. In an inter partes reexamination, members of the Patent Trials and Appeals Board administrative patent judges will reexamine the questioned claim of the issued patent.

Timing Note: An ex parte reexamination can be filed at any time after a patent has been issued. In contrast, an inter partes reexamination can only be sought within the first nine months following the issuance of a patent to question patent validity.

Inter Partes Reexamination Timeline

Inter partes reexaminations are typically completed within one year. A patent owner has three months after a reexamination is requested to file a preliminary response. If and when the response is submitted, the USPTO will come to a decision within three months. Once the reexamination request is accepted or rejected, the patent owner has another three months to respond and motion to amend claims. In the following three more months, the petitioner will reply to the challenged patent owner response with an opposition to amendment. The patent owner then has only one month to reply to the opposition of amendment. A hearing may be requested but will prolong the inter partes reexamination proceedings.

Inter partes reexamination should be considered with caution. It is an expensive petition to research and write costing $5,000 – $25,000 in patent attorney fees. Further, there are multiple government filing fees frequently totaling $45,000 or more.

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