Canada: Methods Of Medical Treatment – A New Twist On An Old Prohibition

Last Updated: November 28 2006

Article by Santosh Chari, © 2006, Blake, Cassels & Graydon LLP

Originally published in Blakes Bulletin on Intellectual Property, November 2006

It has long been established in Canada that claims to methods of medical treatment are not patentable. However, many such claims can often be re-written as "use" or "composition" claims, which have generally been found acceptable. In Axcan Pharma Inc. v. Pharmascience Inc. (Axcan), the Federal Court has cast doubt on the viability of this approach.


In Canada, the marketing of a drug requires regulatory approval in the form of a Notice of Compliance (NOC). If someone, such as a generic manufacturer, seeks a further NOC for a patented drug, but is not the patentee or someone authorized under the patentee, the issuance of the NOC will depend upon showing that the manufacture of the drug will not infringe any patents listed on the Patent Register associated with the first NOC. In such cases, the person seeking the NOC may argue non-infringement of the listed patent or patents by showing: (1) that the relevant patents (as listed on the Patent Register) are expired; (2) that its manufacture of the drug will not infringe any listed patents; or (3) that the listed patents are invalid. Such allegations are rebuttable by the patentee by an application to the Federal Court. For further discussion on the Patented Medicines (Notice of Compliance) Regulations and the Canadian government’s recent amendments see Canada Amends Regulations Governing Drug Approval Process in this issue of Blakes Bulletin on Intellectual Property.


The "linkage" of marketing approval for a medicine to the status of its patent protection has resulted in a considerable amount of litigation in Canada. These cases have also provided a fair amount of jurisprudence on issues of the infringement and validity of patents. Axcan is an example of one such case.

Axcan obtained Canadian patent number 1,318,590 (the ’590 patent) on June 1, 1993 based on a patent application filed on November 18, 1987. The ’590 patent is directed to ursodeoxycholic acid, or Ursodiol, which is used in the treatment of primary biliary cirrhosis. The patent is listed on the Patent Register associated with the NOC for the subject drug.

The ’590 patent includes the following single claim directed to a composition containing Ursodiol:

"Pharmaceutical composition for the treatment of primary biliary cirrhosis, characterized in that it includes ursodeoxycholic acid as well as a vehicle and if necessary pharmaceutical excipients, the said composition being processed in a form allowing for the said treatment of primary biliary cirrhosis based on a dose of 13 to 15 mg/kg/day."

Pharmascience, a generic manufacturer, applied for an NOC for its version of Ursodiol alleging non-infringement of the ’590 patent on the basis that the sole claim of the patent was invalid. In particular, Pharmascience alleged that the claim lacked novelty in view of a prior publication and that the claim was invalid for being directed to non-patentable subject matter. On the latter point, Pharmascience alleged that the claim, although reciting a composition, was directed to a method of medical treatment. Axcan applied to the Federal Court for an order prohibiting the issuance of an NOC to Pharmascience and argued against the allegations.

The Axcan Decision

In forming its decision, the Court first construed the claim of the ’590 patent and found that the dosage of 13 to 15 mg/kg/ day was an essential element of the invention. The Court reasoned that the recitation in the claim of a specific dosage range, and the lack of any other claims in the patent supported such conclusion. The Court then addressed the prior art, which included prior knowledge of Ursodiol (which was known as a liver medication since 1957) and the prior publication of a dosage of 10 mg/kg/day of the drug for treating chronic liver diseases. Notwithstanding this, the Court found the claim to be novel for reciting a dosage range outside the teachings of the prior art. The Court also commented that, were it not for the dosage constituting an essential element of the claim, it would have failed for lack of novelty.

The Court then turned to Pharmascience’s allegation that the claim was directed to a method of medical treatment. Citing prior Supreme Court of Canada decisions, the Court first reiterated the prohibition in Canada against patenting methods of medical treatment. The Court pointed out that prior decisions also held that a new use for a known compound, pharmaceutical or otherwise, may comprise patentable subject matter. However, the Court went on to find that the "composition" claim of the ’590 patent comprised a "method of medical treatment" and, therefore, held the claim to be invalid.

In its reasoning, the Court stated that the essential element of a specific dosage regime (i.e., mg/kg/day) recited in the claim requires the intervention of a medical practitioner to prescribe Ursodiol at amounts that vary from one patient to another. As stated by the Court:

"It is up to the physician based on his or her knowledge of the patient’s rate of metabolism and other factors to determine the appropriate daily dosage … There is a distinction between the dosage in a capsule and a dosage range based on the patient’s weight. As I read the claim, the emphasis is on the dosage range, and a dosage range is not a vendable (sic) product."

On finding the sole claim of the ’590 patent to be invalid for claiming non-patentable subject matter, the Court found no reason to prohibit the issuance of an NOC to Pharmascience.


It is common in Canada to claim a new use of a drug or a new composition containing the drug instead of claiming a method of treatment. Quite often, such use or composition claims also recite a dosage of the drug based on the weight of the patient being treated as opposed to pre-set dosage formulations. In light of the comments made by the Court in Axcan, the viability of enforcing such claims may now be questionable.

It should be noted that the issue addressed by the Court was restricted to whether Pharmascience should be prohibited from obtaining an NOC for Ursodiol. The Court’s decision does not have any direct effect on the validity of the ’590 patent. However, the direction taken by the Court in its interpretation of the ’590 claim may have future ramifications.

In view of the Axcan decision, care should be taken when drafting claims to drug compositions or uses to avoid incorporating elements that may be construed as a treatment step.

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.

Events from this Firm
27 Oct 2016, Seminar, Toronto, Canada

Please join members of the Blakes Commercial Real Estate group as they discuss five key provisions of a commercial real estate purchase agreement that are often the subject of much negotiation but are sometimes misunderstood.

1 Nov 2016, Seminar, Toronto, Canada

What is the emotional culture of your organization?

Every organization and workplace has an emotional culture that can have an impact on everything from employee performance to customer or client satisfaction.

3 Nov 2016, Seminar, Toronto, Canada

Join leading lawyers from the Blakes Pensions, Benefits & Executive Compensation group as they discuss recent updates and legal developments in pension and employee benefits law as well as strategies to identify and minimize common risks.

In association with
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
Check to state you have read and
agree to our Terms and Conditions

Terms & Conditions and Privacy Statement (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

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’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.


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.


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 by clicking here .

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 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.


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.


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.


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.


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

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

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

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