Canada: Teva v Pfizer, Or The "Viagra Saga": If There Is No Quid — Proper Disclosure — There Can Be No Quo — Exclusive Monopoly Rights

Last Updated: November 27 2012
Article by Christelle Gedeon and Joanie Lapalme

Sildenafil is the active ingredient in Viagra, the blockbuster potency-enhancing drug marketed by Pfizer. The Canadian sildenafil patent saga came to an end on November 8, 2012, when the Supreme Court of Canada declared the patent void, a year and a half prior to its expiry. In doing so, the Supreme Court clarified the law on sufficient disclosure, as well as the relationship between a patent, the invention it protects, and the claims which define the patent monopoly. In its judgment, the Supreme Court also provided a few tantalizing hints about its views on disclosure and the doctrine of sound prediction, but declined to rule on that issue, as the case involved demonstrated, rather than predicted, utility.

The facts in the Pfizer decision are uncharacteristically straightforward. The patent claims were constructed using a cascading structure of claims, with the broadest independent claim, Claim 1 disclosing "formula I" – which included 260 quintillion possible compounds. This massive family of compounds was then progressively narrowed in dependant Claims 2 through 5, with Claim 5 consisting of only nine compounds. Of these nine compounds, Claims 6 and 7, described in the patent as "especially preferred embodiments" of the invention, each disclosed a single and distinct compound. Sildenafil was the compound disclosed in Claim 7.

Since sildenafil already existed at the time the patent was awarded, the inventive concept of the patent was not sildenafil itself, but rather the use of sildenafil for the treatment of erectile dysfunction. Teva argued that since the claims of the patent, as drafted, ended with two individually claimed compounds, only one of which was sildenafil, the true invention was obscured.  As such, the disclosure failed to state the invention in clear terms.

Pfizer denied the ambiguity of the patent and added that in light of case law and section 58 of the Patent Act, courts are required to consider valid and invalid claims separately. Thus, even if the patent's Claims 1 to 5 were held invalid, the invalidity of those claims would not affect Claim 7 thereby ensuring that sildenafil would remain protected by the patent monopoly.

Pfizer's arguments regarding the severability of claims succeeded in the lower courts. Despite the Federal Court's characterization of Claims 1 to 5 as "red herrings" creating ambiguity in Pfizer's patent, the patent was upheld.  Guided by existing case law, the Court examined the validity of each claim within the patent on an individual basis. Although the trial judge doubted the validity of Claims 1 to 5, when he arrived at Claim 7, he concluded that it was valid since it disclosed a single compound. As such, there could be no ambiguity and Teva's request for authorization to produce a generic version of Viagra was denied.

The Federal Court of Appeal also upheld the validity of the patent on the basis of its construction of section 58 of the Patent Act. The earlier claims were problematic because they disclosed a class of compounds without providing the reader with a mechanism to select the sole effective compound from the class. But Claim 7 disclosed a single compound thereby obviating the selection problem. The Federal Court of Appeal further held that the sufficiency of the patent's disclosure could be assessed in answering two questions: "What is the invention?" and "How does it work?" The Court of Appeal found that both requirements were met by Claim 7.

In a unanimous (7-0) decision, the Supreme Court of Canada overruled the lower courts on two grounds. First, the Supreme Court held that a patent must be examined as a whole, rejecting the claim-by-claim analysis used by the lower courts. The Supreme Court noted that while section 58 of the Patent Act provides that valid claims are not affected by invalid claims, this provision does not mandate that courts assess a patent's validity on a claim-by-claim basis. Instead, the Supreme Court explained that a patent discloses a single invention, and that it is this invention which must satisfy the validity requirements of the Patent Act. The patent's claims merely describe the scope of the economic monopoly. Thus, if the patent as a whole fails to sufficiently disclose the invention, the patent cannot be saved by inviting the judge to apply the sufficient disclosure test to a single claim, as had occurred in the lower courts.

Second, the Supreme Court held that the lower courts had misunderstood the test for sufficient disclosure. The Supreme Court clarified that the relevant test was not the simple two-question test used by the lower courts (i.e. "What is your invention? How does it work?"). Rather, the correct test was whether a skilled person could, using only the information contained in the specification, produce the invention described therein. Pfizer's patent required of users to perform experiments in order to discover whether it was Claim 6 or Claim 7 that disclosed the effective compound. Since the patent required further experimentation in order to put the invention into practice, there was insufficient disclosure. As such, the patent failed to enable the public to decipher that sildenafil, as opposed to the other compounds claimed within the class, was the active and useful compounds for the treatment of erectile dysfunction.  Consequently, the patent was void

www.fasken.com

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.

Authors
 
In association with
Related Video
Up-coming Events Search
Tools
Print
Font Size:
Translation
Channels
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
Password
Confirm Password
Position
Mondaq Topics -- Select your Interests
 Accounting
 Anti-trust
 Commercial
 Compliance
 Consumer
 Criminal
 Employment
 Energy
 Environment
 Family
 Finance
 Government
 Healthcare
 Immigration
 Insolvency
 Insurance
 International
 IP
 Law Performance
 Law Practice
 Litigation
 Media & IT
 Privacy
 Real Estate
 Strategy
 Tax
 Technology
 Transport
 Wealth Mgt
Regions
Africa
Asia
Asia Pacific
Australasia
Canada
Caribbean
Europe
European Union
Latin America
Middle East
U.K.
United States
Worldwide Updates
Registration
Mondaq Ltd requires you to register and provide information that personally identifies you, including what sort of information you are interested in, for three primary purposes:
  • To allow you to personalize the Mondaq websites you are visiting.
  • To enable features such as password reminder, newsletter alerts, email a colleague, and linking from Mondaq (and its affiliate sites) to your website.
  • To produce demographic feedback for our information providers who provide information free for your use.
  • Mondaq (and its affiliate sites) do not sell or provide your details to third parties other than information providers. The reason we provide our information providers with this information is so that they can measure the response their articles are receiving and provide you with information about their products and services.
    If you do not want us to provide your name and email address you may opt out by clicking here
    If you do not wish to receive any future announcements of products and services offered by Mondaq you may opt out by clicking here

    Terms & Conditions and Privacy Statement

    Mondaq.com (the Website) is owned and managed by Mondaq Ltd and as a user you are granted a non-exclusive, revocable license to access the Website under its terms and conditions of use. Your use of the Website constitutes your agreement to the following terms and conditions of use. Mondaq Ltd may terminate your use of the Website if you are in breach of these terms and conditions or if Mondaq Ltd decides to terminate your license of use for whatever reason.

    Use of www.mondaq.com

    You may use the Website but are required to register as a user if you wish to read the full text of the content and articles available (the Content). 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 & conditions or with the prior written consent of Mondaq Ltd. You may not use electronic or other means to extract details or information about Mondaq.com’s content, users or contributors in order to offer them any services or products which compete directly or indirectly with Mondaq Ltd’s services and products.

    Disclaimer

    Mondaq Ltd and/or its respective suppliers make no representations about the suitability of the information contained in the documents and related graphics published on this server for any purpose. All such documents and related graphics are provided "as is" without warranty of any kind. Mondaq Ltd and/or its respective suppliers hereby disclaim all warranties and conditions with regard to this information, including all implied warranties and conditions of merchantability, fitness for a particular purpose, title and non-infringement. In no event shall Mondaq Ltd 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 or performance of information available from this server.

    The documents and related graphics published on this server could include technical inaccuracies or typographical errors. Changes are periodically added to the information herein. Mondaq Ltd and/or its respective suppliers may make improvements and/or changes in the product(s) and/or the program(s) described herein at any time.

    Registration

    Mondaq Ltd requires you to register and provide information that personally identifies you, including what sort of information you are interested in, for three primary purposes:

    • To allow you to personalize the Mondaq websites you are visiting.
    • To enable features such as password reminder, newsletter alerts, email a colleague, and linking from Mondaq (and its affiliate sites) to your website.
    • To produce demographic feedback for our information providers who provide information free for your use.

    Mondaq (and its affiliate sites) do not sell or provide your details to third parties other than information providers. The reason we provide our information providers with this information is so that they can measure the response their articles are receiving and provide you with information about their products and services.

    Information Collection and Use

    We require site users to register with Mondaq (and its affiliate sites) to view the free information on the site. We also collect information from our users at several different points on the websites: this is so that we can customise the sites according to individual usage, provide 'session-aware' functionality, and ensure that content is acquired and developed appropriately. This gives us an overall picture of our user profiles, which in turn shows to our Editorial Contributors the type of person they are reaching by posting articles on Mondaq (and its affiliate sites) – meaning more free content for registered users.

    We are only able to provide the material on the Mondaq (and its affiliate sites) site free to site visitors because we can pass on information about the pages that users are viewing and the personal information users provide to us (e.g. email addresses) to reputable contributing firms such as law firms who author those pages. We do not sell or rent information to anyone else other than the authors of those pages, who may change from time to time. Should you wish us not to disclose your details to any of these parties, please tick the box above or tick the box marked "Opt out of Registration Information Disclosure" on the Your Profile page. We and our author organisations may only contact you via email or other means if you allow us to do so. Users can opt out of contact when they register on the site, or send an email to unsubscribe@mondaq.com with “no disclosure” in the subject heading

    Mondaq News Alerts

    In order to receive Mondaq News Alerts, users have to complete a separate registration form. This is a personalised service where users choose regions and topics of interest and we send it only to those users who have requested it. Users can stop receiving these Alerts by going to the Mondaq News Alerts page and deselecting all interest areas. In the same way users can amend their personal preferences to add or remove subject areas.

    Cookies

    A cookie is a small text file written to a user’s hard drive that contains an identifying user number. The cookies do not contain any personal information about users. We use the cookie so users do not have to log in every time they use the service and the cookie will automatically expire if you do not visit the Mondaq website (or its affiliate sites) for 12 months. We also use the cookie to personalise a user's experience of the site (for example to show information specific to a user's region). As the Mondaq sites are fully personalised and cookies are essential to its core technology the site will function unpredictably with browsers that do not support cookies - or where cookies are disabled (in these circumstances we advise you to attempt to locate the information you require elsewhere on the web). However if you are concerned about the presence of a Mondaq cookie on your machine you can also choose to expire the cookie immediately (remove it) by selecting the 'Log Off' menu option as the last thing you do when you use the site.

    Some of our business partners may use cookies on our site (for example, advertisers). However, we have no access to or control over these cookies and we are not aware of any at present that do so.

    Log Files

    We use IP addresses to analyse trends, administer the site, track movement, and gather broad demographic information for aggregate use. IP addresses are not linked to personally identifiable information.

    Links

    This web site contains links to other sites. Please be aware that Mondaq (or its affiliate sites) are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of these third party sites. This privacy statement applies solely to information collected by this Web site.

    Surveys & Contests

    From time-to-time our site requests information from users via surveys or contests. Participation in these surveys or contests is completely voluntary and the user therefore has a choice whether or not to disclose any information requested. Information requested may include contact information (such as name and delivery address), and demographic information (such as postcode, age level). Contact information will be used to notify the winners and award prizes. Survey information will be used for purposes of monitoring or improving the functionality of the site.

    Mail-A-Friend

    If a user elects to use our referral service for informing a friend about our site, we ask them for the friend’s name and email address. Mondaq stores this information and may contact the friend to invite them to register with Mondaq, but they will not be contacted more than once. The friend may contact Mondaq to request the removal of this information from our database.

    Emails

    From time to time Mondaq may send you emails promoting Mondaq services including new services. You may opt out of receiving such emails by clicking below.

    *** If you do not wish to receive any future announcements of services offered by Mondaq you may opt out by clicking here .

    Security

    This website takes every reasonable precaution to protect our users’ information. When users submit sensitive information via the website, your information is protected using firewalls and other security technology. If you have any questions about the security at our website, you can send an email to webmaster@mondaq.com.

    Correcting/Updating Personal Information

    If a user’s personally identifiable information changes (such as postcode), or if a user no longer desires our service, we will endeavour to provide a way to correct, update or remove that user’s personal data provided to us. This can usually be done at the “Your Profile” page or by sending an email to EditorialAdvisor@mondaq.com.

    Notification of Changes

    If we decide to change our Terms & Conditions or Privacy Policy, we will post those changes on our site so our users are always aware of what information we collect, how we use it, and under what circumstances, if any, we disclose it. If at any point we decide to use personally identifiable information in a manner different from that stated at the time it was collected, we will notify users by way of an email. Users will have a choice as to whether or not we use their information in this different manner. We will use information in accordance with the privacy policy under which the information was collected.

    How to contact Mondaq

    You can contact us with comments or queries at enquiries@mondaq.com.

    If for some reason you believe Mondaq Ltd. has not adhered to these principles, please notify us by e-mail at problems@mondaq.com and we will use commercially reasonable efforts to determine and correct the problem promptly.

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