Canada: Utility, Sound Prediction And Promise Of The Patent

In recent years, attacks on the lack of sound prediction and failure to meet the promise of the patent have proven to be a crushing hammer in the hands of those who challenge patents. This article considers the Canadian patent utility requirements that extend beyond mere usefulness.

Promise of the Patent

The utility of each claim is assessed against what has been called "the promise of the patent." Traditionally, utility requirements were easily met. Although courts indicated that, where no specific promise is made, the threshold required for utility is low, much ink has been spilled construing patents for specific promises that will void a patent if not met by the claimed invention.

What constitutes a promise is a question of law that courts determine at the Canadian filing date of the patent. The judge is to purposively construe the patent and its context, assisted by factual evidence and expert testimony as to the state of the art and the research conducted until the Canadian filing date, informed by objective and subjective considerations. Advantages described in support of inventive ingenuity have also been considered promises of utility (even though utility and advantages are clearly different). Construing a promise is different from claim construction but may introduce language into the claim, adding limitations.

Patents can now fail as a result of inutility where the patent promises a specific result, but does not deliver. Such attacks have become commonplace. Patents are scrutinized for words and phrases that inflate the promise of a specific result for which the utility has not been demonstrated or soundly predicted. For example, a compound claim can be transformed into a use claim as a result of construing a promise that the compound has a particular utility.

A patentee should not over-promise by suggesting utility for the claimed invention that is not inferable in interpreting the promise from the context of the research and development work that was done prior to the Canadian filing date, even where that research was done to show the claimed invention was inventive over prior art. Caution should be applied when disclosing lists of potential uses for which there is no specific support. Exclusion of such lists, however, may prejudice the patent in other jurisdictions so caution is warranted.

Demonstrated Utility

There were two lines of cases in the Courts with respect to whether or not a patentee must disclose the utility that is demonstrated. In the Viagra decision of late last year, the Supreme Court affirmed there is no requirement to disclose what is demonstrated. One also need not prove the utility conclusively; a strong suggestion of utility by the Canadian filing date is sufficient. However, one cannot rely on post-filing data for demonstrated utility.

Soundly Predicted Utility

It is also possible to have a sound prediction of utility. A sound prediction requires a prima facie reasonable inference of utility. Courts have required patentees to support predictions of utility (and advantages) with a factual basis: a line of reasoning by which predictions of that the claimed invention will meet the promise of utility and a proper disclosure. The Supreme Court of Canada in the AZT case indicated only that one needed the elements of a factual basis, sound line of reasoning and proper disclosure without explaining these requirements. Subsequent cases have interpreted this to mean the factual basis and line of reasoning needs to be disclosed, at least in part, in the patent.

Although the Supreme Court dealt with disclosure requirements for sufficiency in the Viagra case, the Court did not deal with enhanced disclosure requirements for sound prediction. Some have nonetheless argued that heightened disclosure is required. Patent drafters should consider including support for a factual basis and a sound line of reasoning by which the inventors predicted the utility of a claimed invention.

Post-filing data cannot be used to prove a prediction was soundly made or was, in fact, correct. However, a prediction need not be correct if it was soundly made as of the Canadian filing date and the claimed invention has the promised utility. If the reason for utility was subsequently discovered to be different from that disclosed in the line of reasoning, this should not be fatal to the patent since one need not explain why an invention works, only what it is and how to practice it. Hence an enhanced disclosure requirement for sound predictions of utility seems at odds with Canadian law on sufficiency. Hopefully, the Supreme Court will take the opportunity to make the law consistent on this point and indicate that disclosure requirements for sufficiency and utility are the same and no enhanced disclosure requirement exists for utility regardless of whether utility is demonstrated or soundly predicted.

What this Means for Patentees

The following are four tips for patentees:

1. To support a sound prediction of utility, consider including as much information in any application for the factual basis and line of reasoning, e.g. reference to the state of the art, hypotheses, descriptions of work done, tests and results.

2. Add additional information to the patent specification learned during the period between priority filing and the Canadian filing date. Note, however, the Canadian filing date for PCT applications is the PCT filing date and it is too late to supplement the disclosure upon National Entry in Canada.

3. Consider each claim individually and what support exists in the disclosure for it.

When claiming a broad genus, claim various preferred sub-genera and preferred species disclosed which are especially relevant to the work done. Where one is claiming new uses, have claims that mirror the actual commercial use as separate independent claims, distinct from potential uses inferable from initial research.

4. Be aware of how statements of advantage, or discussion of potential applications may be argued to be promises of the patent.

Utility in Canada is a fertile ground for invalidity attacks compared with Europe or the United States. However, where one promises more than one's claimed invention can deliver, a patentee may face jeopardy in numerous jurisdictions, not just Canada. Therefore, before including a statement of advantage or a statement of utility about the claimed invention, one must think about how that statement can be supported, either with information in the patent or with information that would be understood at the filing date of the patent.

Patentees may either draft applications specific to Canada or ensure applications are drafted in such a manner that there is support in the disclosure for any advantages described, or promises made, and subject matter claimed. Because this analysis begins and ends with the claimed invention, it is wise to review the scope of claims to ensure, where possible, narrow claims are available that cover the key aspects of the invention that are the most critical to the commercial product.

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

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

Similar Articles
Relevancy Powered by MondaqAI
In association with
Related Topics
Similar Articles
Relevancy Powered by MondaqAI
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 (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

To Use 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