The Practicing the Prior Art [Self] Defense Box

by Harness, Dickey & Pierce, PLC

Harness, Dickey & Pierce, PLC

In 01 Communique, the Federal Circuit provided clear guidelines regarding the frequently raised “practicing the prior art” argument.  Quite simply, the argument that a defendant is not liable because the claimed elements existed in the prior art is an invalidity argument, not a non-infringement argument.

By way of background, 01 Communique sued Citrix alleging patent infringement relating to private communication portals.  Citrix argued that its accused products did not literally infringe the asserted claims and the asserted claims were invalid.  In a somewhat Solomon-esque decision, the jury determined that 1) Citrix did not prove that the claims were invalid, and 2) that 01 Communique failed to prove that Citrix infringed the asserted claims.

01 Communique moved for a new trial alleging that Citrix improperly resorted to a “well-known defendant’s trick” by arguing that Citrix’s products were the same as prior art products and therefore, Citrix’s products could not infringe the asserted claims.  The District Court denied O1 Communique’s motion stating that 1) the jury had properly been instructed that infringement analysis requires comparing the asserted claims to the accused product, and 2) that Citrix did not raise a “practicing the prior art” argument in its non-infringement defense.  01 Communique appealed.

In affirming the District Court, the Federal Circuit reiterated that “there is no ‘practicing the prior art’ defense to literal infringement.”  Instead, “literal infringement is determined by construing the claims and comparing them to the accused device, not by comparing the accused device to the prior art.”  Therefore, an accused infringer “cannot defeat a claim of literal infringement or establish invalidity merely by pointing to similarities between an accused product and the prior art.”  Thus, the prior art’s similarities to the accused product does not matter for infringement purposes.

It’s a different analysis when it comes to invalidity.  A frequent defense argument is that, assuming the asserted claims are valid, if the plaintiff tried to expand the scope of its claims to read on defendant’s products, then those claims are invalid in light of the prior art.  The Federal Circuit affirmed that there is “nothing improper about this argument.”  Therefore, a defendant may properly argue “that if a claim term must be broadly interpreted to read on an accused device, then this same broad construction will read on the prior art.”  Thus, in this context, the comparison of the prior art to the defendant’s accused products is relevant, but only by way of limiting the scope of the asserted claim.

That said, a “practicing the prior art” argument is still subjected to the “clear and convincing” standard for proving invalidity, not the “less stringent preponderance of the evidence standard.”  But don’t let the standard scare you — as the Federal Circuit has recognized, if the accused product actually practices the prior art and nothing more, invalidity should be easy to prove.  In fact, “when an accused product and the prior art are closely aligned, it takes exceptional linguistic dexterity to simultaneously establish infringement and evade invalidity.”

In a way, the relevance of the prior art to the asserted claims and accused products seems like procedural semantics. But, as with everything, context matters.

DISCLAIMER: Because of the generality of this update, the information provided herein may not be applicable in all situations and should not be acted upon without specific legal advice based on particular situations.

© Harness, Dickey & Pierce, PLC | Attorney Advertising

Written by:

Harness, Dickey & Pierce, PLC

Harness, Dickey & Pierce, PLC on:

Readers' Choice 2017
Reporters on Deadline

"My best business intelligence, in one easy email…"

Your first step to building a free, personalized, morning email brief covering pertinent authors and topics on JD Supra:
Sign up using*

Already signed up? Log in here

*By using the service, you signify your acceptance of JD Supra's Privacy Policy.
Custom Email Digest
Privacy Policy (Updated: October 8, 2015):

JD Supra provides users with access to its legal industry publishing services (the "Service") through its website (the "Website") as well as through other sources. Our policies with regard to data collection and use of personal information of users of the Service, regardless of the manner in which users access the Service, and visitors to the Website are set forth in this statement ("Policy"). By using the Service, you signify your acceptance of this Policy.

Information Collection and Use by JD Supra

JD Supra collects users' names, companies, titles, e-mail address and industry. JD Supra also tracks the pages that users visit, logs IP addresses and aggregates non-personally identifiable user data and browser type. This data is gathered using cookies and other technologies.

The information and data collected is used to authenticate users and to send notifications relating to the Service, including email alerts to which users have subscribed; to manage the Service and Website, to improve the Service and to customize the user's experience. This information is also provided to the authors of the content to give them insight into their readership and help them to improve their content, so that it is most useful for our users.

JD Supra does not sell, rent or otherwise provide your details to third parties, other than to the authors of the content on JD Supra.

If you prefer not to enable cookies, you may change your browser settings to disable cookies; however, please note that rejecting cookies while visiting the Website may result in certain parts of the Website not operating correctly or as efficiently as if cookies were allowed.

Email Choice/Opt-out

Users who opt in to receive emails may choose to no longer receive e-mail updates and newsletters by selecting the "opt-out of future email" option in the email they receive from JD Supra or in their JD Supra account management screen.


JD Supra takes reasonable precautions to insure that user information is kept private. We restrict access to user information to those individuals who reasonably need access to perform their job functions, such as our third party email service, customer service personnel and technical staff. However, please note that no method of transmitting or storing data is completely secure and we cannot guarantee the security of user information. Unauthorized entry or use, hardware or software failure, and other factors may compromise the security of user information at any time.

If you have reason to believe that your interaction with us is no longer secure, you must immediately notify us of the problem by contacting us at In the unlikely event that we believe that the security of your user information in our possession or control may have been compromised, we may seek to notify you of that development and, if so, will endeavor to do so as promptly as practicable under the circumstances.

Sharing and Disclosure of Information JD Supra Collects

Except as otherwise described in this privacy statement, JD Supra will not disclose personal information to any third party unless we believe that disclosure is necessary to: (1) comply with applicable laws; (2) respond to governmental inquiries or requests; (3) comply with valid legal process; (4) protect the rights, privacy, safety or property of JD Supra, users of the Service, Website visitors or the public; (5) permit us to pursue available remedies or limit the damages that we may sustain; and (6) enforce our Terms & Conditions of Use.

In the event there is a change in the corporate structure of JD Supra such as, but not limited to, merger, consolidation, sale, liquidation or transfer of substantial assets, JD Supra may, in its sole discretion, transfer, sell or assign information collected on and through the Service to one or more affiliated or unaffiliated third parties.

Links to Other Websites

This Website and the Service may contain links to other websites. The operator of such other websites may collect information about you, including through cookies or other technologies. If you are using the Service through the Website and link to another site, you will leave the Website and this Policy will not apply to your use of and activity on those other sites. We encourage you to read the legal notices posted on those sites, including their privacy policies. We shall have no responsibility or liability for your visitation to, and the data collection and use practices of, such other sites. This Policy applies solely to the information collected in connection with your use of this Website and does not apply to any practices conducted offline or in connection with any other websites.

Changes in Our Privacy Policy

We reserve the right to change this Policy at any time. Please refer to the date at the top of this page to determine when this Policy was last revised. Any changes to our privacy policy will become effective upon posting of the revised policy on the Website. By continuing to use the Service or Website following such changes, you will be deemed to have agreed to such changes. If you do not agree with the terms of this Policy, as it may be amended from time to time, in whole or part, please do not continue using the Service or the Website.

Contacting JD Supra

If you have any questions about this privacy statement, the practices of this site, your dealings with this Web site, or if you would like to change any of the information you have provided to us, please contact us at:

- hide
*With LinkedIn, you don't need to create a separate login to manage your free JD Supra account, and we can make suggestions based on your needs and interests. We will not post anything on LinkedIn in your name. Or, sign up using your email address.