United States: After SAS, Will Estoppel Also Apply To Grounds Not Included In Petitions For Inter Partes Review And Post-Grant Review?

Last Updated: December 13 2018
Article by Marc K. Weinstein

      Since the Supreme Court's decision in SAS Institute Inc. v. Iancu, 138 S. Ct. 1348 (2018), there has been significant discussion on SAS's expected effect on estoppel for IPRs.  Essentially universal opinion holds that estoppel will apply to all grounds raised in the IPR petition due to the all-or-nothing institution standard applied by the Patent Trial and Appeal Board ("PTAB") in response to SAS.  Post-SAS, final written decisions in IPRs will address all grounds raised in the petition if at least one ground meets the standard for institution, thus making estoppel applicable to all petition grounds as grounds "that the petitioner raised ... during that inter partes review" under 35 U.S.C. § 315(e).

      Other discussion of SAS's effect on estoppel for IPRs has addressed whether estoppel should apply to grounds not raised in the petition.  Prior to SAS, a conflict existed in district courts on this issue, with some courts finding estoppel applies and others not.  But given the PTAB's all-or-nothing institution standard, it logically follows that grounds based on any prior art known by petitioner or that could have been found by a skilled searcher's diligent search at the time the petition was filed would be a "ground that the petitioner ... reasonably could have raised during that inter partes review" under 35 U.S.C. § 315(e).  In particular, since all grounds in a petition will now be considered if the petition is instituted, the grounds considered during the IPR clearly could have included any grounds based on the prior art known by petitioner or that could have been found by a skilled searcher's diligent search at the time the petition was filed. 

      Accordingly, post-SAS, it is reasonable to conclude that estoppel should also apply to grounds not included in the IPR petition with an exception for grounds based on prior art that could not have been found by a skilled searcher's diligent search.  Other than this narrow exception, the petitioner would be estopped from raising any prior art invalidity grounds in a district court or the ITC.  The petitioner of course still retains the right to raise all other invalidity grounds including patentability under § 101, indefiniteness, lack of enablement, and lack of written description under § 112, and non-prior-art-based invalidity under § 102 and § 103, such as on-sale bar or public use.

      In contrast to IPRs, there has been much less discussion of the potential impact of SAS on post-grant reviews ("PGRs"), understandably so given the prevalence of IPRs and the relative scarcity of PGRs.  Nevertheless, it would be expected that all grounds included in the PGR petition will be subject to estoppel if any claims survive a final written decision for the same reasons as for IPRs. 

      But what will the estoppel be for grounds not included in the PGR petition?  If the same estoppel is applied to grounds not raised in a PGR petition as likely applies to IPRs, then the estoppel would apply not only to prior art invalidity, but for all other statutory invalidity bases.  In other words, a PGR petitioner may lose all right to raise an invalidity defense in a district court or the ITC based on §§ 101, 102, 103, and 112.

      The statutory language for IPRs and PGRs supports this conclusion.  The estoppel language in 35 U.S.C. § 325(e) for PGRs is essentially identical to the corresponding language in 35 U.S.C. § 315(e) for IPRs with both sections reciting the same language that the petitioner "may not assert ... that the claim is invalid on any ground that the petitioner raised or reasonably could have raised during that inter partes review."  The identity of this language strongly suggests that estoppel for IPRs should apply in the same manner as IPRs. 

      Moreover, just like invalidity grounds based on prior art known to the petitioner at the time of the IPR petition or that could have been found by a skilled searcher's diligent search, it would be reasonable to conclude that the petitioner knew or reasonably could have known about all other invalidity bases under §§ 101, 102, 103, and 112 at the time of the PGR petition, with possible exceptions for on-sale bars or prior use that might only be found through discovery in litigation. And if IPR estoppel applies to prior art invalidity under both § 102 and § 103, it makes sense that PGR estoppel should not be limited to the statutory invalidity ground or grounds raised in the PGR petition, but to all statutory invalidity grounds available in a PGR.  Accordingly, PGR estoppel for grounds not raised in the petition should apply to all invalidity grounds under §§ 101, 102, 103, and 112 with its own narrow exceptions.

      Should this scope of estoppel apply to grounds not raised in IPR and PGR petitions, IPR petitioners and especially PGR petitioners must consider all potential invalidity grounds and carefully identify which grounds to include before filing a petition.  For IPRs, petitioners with co-pending litigations have sometimes withheld one or more grounds from the petition with the hope of relying on those grounds should the IPR fail.  Such a strategy is unlikely to succeed post-SAS.  Instead, IPR petitioners should expect that, other than the narrow exception, a failed IPR will prevent the petitioner from raising any printed prior art invalidity grounds in the litigation.

      For PGRs, petitioners have often limited the petition to invalidity based on § 101, particularly for software-related patents, or § 112, particularly for pharmaceutical-related patents.  Continuing this strategy for PGR petitioners after SAS may now subject the petitioner to a complete estoppel of all invalidity grounds under §§ 101, 102, 103, and 112, even if one or more of these statutory invalidity grounds was absent from the PGR.  Given the relative recency of the SAS decision and the absence of any judicial decision addressing the estoppel scope post-SAS, PGR petitioners who have subscribed to this strategy since SAS may be unaware of this potentially significant estoppel effect.

      Until district courts and ultimately the Federal Circuit address the estoppel scope for IPRs and PGRs post-SAS, it remains indeterminate if such a penal estoppel scope will apply to grounds not raised in the petition.  In the meantime, IPR and PGR petitioners would be advised to consider this possibility and prepare their petitions accordingly.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.

To print this article, all you need is to be registered on Mondaq.com.

Click to Login as an existing user or Register so you can print this article.

Similar Articles
Relevancy Powered by MondaqAI
Oblon, McClelland, Maier & Neustadt, L.L.P
Finnegan, Henderson, Farabow, Garrett & Dunner, LLP
Finnegan, Henderson, Farabow, Garrett & Dunner, LLP
In association with
Related Topics
Similar Articles
Relevancy Powered by MondaqAI
Oblon, McClelland, Maier & Neustadt, L.L.P
Finnegan, Henderson, Farabow, Garrett & Dunner, LLP
Finnegan, Henderson, Farabow, Garrett & Dunner, LLP
Related Articles
Related Video
Up-coming Events Search
Font Size:
Mondaq on Twitter
Register for Access and our Free Biweekly Alert for
This service is completely free. Access 250,000 archived articles from 100+ countries and get a personalised email twice a week covering developments (and yes, our lawyers like to think you’ve read our Disclaimer).
Email Address
Company Name
Confirm Password
Mondaq Topics -- Select your Interests
 Law Performance
 Law Practice
 Media & IT
 Real Estate
 Wealth Mgt
Asia Pacific
European Union
Latin America
Middle East
United States
Worldwide Updates
Registration (you must scroll down to set your data preferences)

Mondaq Ltd requires you to register and provide information that personally identifies you, including your content preferences, for three primary purposes (full details of Mondaq’s use of your personal data can be found in our Privacy and Cookies Notice):

  • To allow you to personalize the Mondaq websites you are visiting to show content ("Content") relevant to your interests.
  • To enable features such as password reminder, news alerts, email a colleague, and linking from Mondaq (and its affiliate sites) to your website.
  • To produce demographic feedback for our content providers ("Contributors") who contribute Content for free for your use.

Mondaq hopes that our registered users will support us in maintaining our free to view business model by consenting to our use of your personal data as described below.

Mondaq has a "free to view" business model. Our services are paid for by Contributors in exchange for Mondaq providing them with access to information about who accesses their content. Once personal data is transferred to our Contributors they become a data controller of this personal data. They use it to measure the response that their articles are receiving, as a form of market research. They may also use it to provide Mondaq users with information about their products and services.

Details of each Contributor to which your personal data will be transferred is clearly stated within the Content that you access. For full details of how this Contributor will use your personal data, you should review the Contributor’s own Privacy Notice.

Please indicate your preference below:

Yes, I am happy to support Mondaq in maintaining its free to view business model by agreeing to allow Mondaq to share my personal data with Contributors whose Content I access
No, I do not want Mondaq to share my personal data with Contributors

Also please let us know whether you are happy to receive communications promoting products and services offered by Mondaq:

Yes, I am happy to received promotional communications from Mondaq
No, please do not send me promotional communications from Mondaq
Terms & Conditions

Mondaq.com (the Website) is owned and managed by Mondaq Ltd (Mondaq). Mondaq grants you a non-exclusive, revocable licence to access the Website and associated services, such as the Mondaq News Alerts (Services), subject to and in consideration of your compliance with the following terms and conditions of use (Terms). Your use of the Website and/or Services constitutes your agreement to the Terms. Mondaq may terminate your use of the Website and Services if you are in breach of these Terms or if Mondaq decides to terminate the licence granted hereunder for any reason whatsoever.

Use of www.mondaq.com

To Use Mondaq.com you must be: eighteen (18) years old or over; legally capable of entering into binding contracts; and not in any way prohibited by the applicable law to enter into these Terms in the jurisdiction which you are currently located.

You may use the Website as an unregistered user, however, you are required to register as a user if you wish to read the full text of the Content or to receive the Services.

You may not modify, publish, transmit, transfer or sell, reproduce, create derivative works from, distribute, perform, link, display, or in any way exploit any of the Content, in whole or in part, except as expressly permitted in these Terms or with the prior written consent of Mondaq. You may not use electronic or other means to extract details or information from the Content. Nor shall you extract information about users or Contributors in order to offer them any services or products.

In your use of the Website and/or Services you shall: comply with all applicable laws, regulations, directives and legislations which apply to your Use of the Website and/or Services in whatever country you are physically located including without limitation any and all consumer law, export control laws and regulations; provide to us true, correct and accurate information and promptly inform us in the event that any information that you have provided to us changes or becomes inaccurate; notify Mondaq immediately of any circumstances where you have reason to believe that any Intellectual Property Rights or any other rights of any third party may have been infringed; co-operate with reasonable security or other checks or requests for information made by Mondaq from time to time; and at all times be fully liable for the breach of any of these Terms by a third party using your login details to access the Website and/or Services

however, you shall not: do anything likely to impair, interfere with or damage or cause harm or distress to any persons, or the network; do anything that will infringe any Intellectual Property Rights or other rights of Mondaq or any third party; or use the Website, Services and/or Content otherwise than in accordance with these Terms; use any trade marks or service marks of Mondaq or the Contributors, or do anything which may be seen to take unfair advantage of the reputation and goodwill of Mondaq or the Contributors, or the Website, Services and/or Content.

Mondaq reserves the right, in its sole discretion, to take any action that it deems necessary and appropriate in the event it considers that there is a breach or threatened breach of the Terms.

Mondaq’s Rights and Obligations

Unless otherwise expressly set out to the contrary, nothing in these Terms shall serve to transfer from Mondaq to you, any Intellectual Property Rights owned by and/or licensed to Mondaq and all rights, title and interest in and to such Intellectual Property Rights will remain exclusively with Mondaq and/or its licensors.

Mondaq shall use its reasonable endeavours to make the Website and Services available to you at all times, but we cannot guarantee an uninterrupted and fault free service.

Mondaq reserves the right to make changes to the services and/or the Website or part thereof, from time to time, and we may add, remove, modify and/or vary any elements of features and functionalities of the Website or the services.

Mondaq also reserves the right from time to time to monitor your Use of the Website and/or services.


The Content is general information only. It is not intended to constitute legal advice or seek to be the complete and comprehensive statement of the law, nor is it intended to address your specific requirements or provide advice on which reliance should be placed. Mondaq and/or its Contributors and other suppliers make no representations about the suitability of the information contained in the Content for any purpose. All Content provided "as is" without warranty of any kind. Mondaq and/or its Contributors and other suppliers hereby exclude and disclaim all representations, warranties or guarantees with regard to the Content, including all implied warranties and conditions of merchantability, fitness for a particular purpose, title and non-infringement. To the maximum extent permitted by law, Mondaq expressly excludes all representations, warranties, obligations, and liabilities arising out of or in connection with all Content. In no event shall Mondaq and/or its respective suppliers be liable for any special, indirect or consequential damages or any damages whatsoever resulting from loss of use, data or profits, whether in an action of contract, negligence or other tortious action, arising out of or in connection with the use of the Content or performance of Mondaq’s Services.


Mondaq may alter or amend these Terms by amending them on the Website. By continuing to Use the Services and/or the Website after such amendment, you will be deemed to have accepted any amendment to these Terms.

These Terms shall be governed by and construed in accordance with the laws of England and Wales and you irrevocably submit to the exclusive jurisdiction of the courts of England and Wales to settle any dispute which may arise out of or in connection with these Terms. If you live outside the United Kingdom, English law shall apply only to the extent that English law shall not deprive you of any legal protection accorded in accordance with the law of the place where you are habitually resident ("Local Law"). In the event English law deprives you of any legal protection which is accorded to you under Local Law, then these terms shall be governed by Local Law and any dispute or claim arising out of or in connection with these Terms shall be subject to the non-exclusive jurisdiction of the courts where you are habitually resident.

You may print and keep a copy of these Terms, which form the entire agreement between you and Mondaq and supersede any other communications or advertising in respect of the Service and/or the Website.

No delay in exercising or non-exercise by you and/or Mondaq of any of its rights under or in connection with these Terms shall operate as a waiver or release of each of your or Mondaq’s right. Rather, any such waiver or release must be specifically granted in writing signed by the party granting it.

If any part of these Terms is held unenforceable, that part shall be enforced to the maximum extent permissible so as to give effect to the intent of the parties, and the Terms shall continue in full force and effect.

Mondaq shall not incur any liability to you on account of any loss or damage resulting from any delay or failure to perform all or any part of these Terms if such delay or failure is caused, in whole or in part, by events, occurrences, or causes beyond the control of Mondaq. Such events, occurrences or causes will include, without limitation, acts of God, strikes, lockouts, server and network failure, riots, acts of war, earthquakes, fire and explosions.

By clicking Register you state you have read and agree to our Terms and Conditions