Canada: Pharma In Brief - Canada: Federal Court Dismisses Prohibition Application For Valganciclovir Hydrochloride Tablets [VALCYTE®]

Case: Hoffmann-La Roche Limited v. Apotex Inc. et al.
Drug: Valganciclovir hydrochloride (VALCYTE®)
Nature of case: Prohibition application pursuant to PM(NOC) Regulations
Successful party: Apotex Inc.
Date of decision: July 12, 2013


Hoffmann-La Roche Limited ("Roche") brought an application pursuant to section 6 of the Patented Medicines (Notice of Compliance) Regulations for an order prohibiting the Minister of Health from issuing a Notice of Compliance to Apotex Inc. ("Apotex") in respect of its valganciclovir hydrochloride tablets (the "Apotex Product") until the expiry of Canadian Patent No. 2,154,721 (the "'721 Patent").

The '721 Patent relates to a novel antiviral drug, valganciclovir, described as the mono-L-valine ester of ganciclovir, a leading drug for the treatment of certain herpes viruses, particularly cytomegalovirus.  Ganciclovir itself exhibits low oral bioavailability, requiring slow daily intravenous infusion of the drug.

Apotex alleged that the '721 Patent was invalid on the basis of anticipation, obviousness and overbreadth, and that its Apotex Product would not infringe certain claims of the '721 Patent.  In its analysis, the Court expanded the disclosure component of the anticipation test, departing from the more stringent test set forth by the Supreme Court of Canada in Apotex Inc. v. Sanofi-Synthelabo Canada Inc. (2008 SCC 61) ("Sanofi").  The Court held that Apotex's invalidity allegations with respect to anticipation and obviousness were justified.  The Court also found that Apotex's allegation of non-infringement was justified in respect of one of the '721 Patent's claims.  As such, the Court dismissed Roche's prohibition application.

The inventive concept of the '721 Patent

The parties disagreed as to whether the '721 Patent claims that the mono-L-valine ester of ganciclovir, valganciclovir, has better oral bioavailability than other esters of ganciclovir, including the bis-valine ester, disclosed in EP '329 (European Patent) or whether it only claims that valganciclovir is better than ganciclovir itself.

The Court found that the '721 Patent does not assert that the invention is an improvement over the esters disclosed in a prior application (EP '329), but rather only asserts that the invention is an improvement over the parent compound, ganciclovir.  The Court also rejected Apotex's argument that the invention of the '721 Patent is crystalline valganciclovir and its salts, finding that crystallinity should be construed as an additional advantage rather than the only advantage.

The Court concluded that the inventive concept of the '721 Patent is the invention of valganciclovir, a stable prodrug with low toxicity and improved oral bioavailability over ganciclovir.

Is the '721 Patent a selection patent?

Roche submitted that EP '329 disclosed a class of compounds that encompassed valganciclovir and that the '721 Patent was a selection from that class.  Apotex submitted that the '721 Patent did not meet the criteria of a selection patent as it did not disclose the special advantage(s) of the selected compound, namely the oral bioavailability advantage of valganciclovir  over the esters of ganciclovir encompassed by EP '329.

The Court agreed with Apotex that no such disclosure was made and that the invention of the '721 Patent relates to a formulation of a new prodrug that is an improvement over the previously invented ganciclovir compound.  The Court concluded that the '721 Patent is not a selection patent.


The Court's approach to anticipation, which blended the test set forth by the Supreme Court of Canada in Sanofi with a number of principles set out by Justice Hughes in Abbott Laboratories v. Sandoz Canada Inc. (2008 FC 1359), can be summarized as follows:  (1) the disclosure need not be an "exact description"; (2) the disclosure need only be sufficient to be read and understood without trial and error when read by a person skilled in the art willing to understand; and (3) the disclosure must enable the skilled person to carry out what is disclosed based on their common general knowledge and allowing for a certain amount of trial and error experimentation.

Based on this approach, the Court came to the conclusion that although EP '329 prefers and exemplifies only the bis-esters, the mono-esters were nonetheless disclosed as well and the person skilled in the art would read EP '329 and understand that it was teaching both mono- and bis-esters with improved bioavailability over ganciclovir.  Given this disclosure of EP '329, the skilled person would engage in routine chemistry and no further inventive step would be required.  The Court found that EP '329 anticipated the invention claimed in the '721 Patent, valganciclovir.


The Court applied the four-step test for assessing obviousness as laid out by the Supreme Court of Canada in Sanofi. The analysis ultimately focused on the fourth step: whether the invention of the '721 Patent was obvious to try.

As part of the obvious to try analysis, the Court considered whether it was more or less self-evident that the formation of the mono-L-valine ester of ganciclovir would result in improved bioavailability, stability and low toxicity as compared to ganciclovir.  The Roche experts noted the range of prior art and expressed the view that the prior art taught away from mono-esters, that acyclovir and ganciclovir are different compounds and that improved bioavailability would not be predicted or expected without testing.  The Court agreed with Apotex's experts that both the encouraging results of valaciclovir, a valine ester of acyclovir (an antiviral nucleoside which Apotex argued was structurally and chemically similar to ganciclovir), and the improved bioavailability using mono-esters and bis-esters claimed in EP '329 would have directed the skilled person to follow the acyclovir model which would have led directly to the invention of valganciclovir.

The Court concluded it would have been more or less self-evident that adding the mono-L-valine ester to ganciclovir would also result in increased bioavailability over ganciclovir.  As a result, the Court found the invention of the '721 Patent to be obvious.


The Court rejected Apotex's argument that certain claims of the '721 Patent are overbroad for claiming crystalline and non-crystalline (amorphous) compounds.  The Court found that the inventive concept of the '721 Patent was not crystallinity and the patent discloses both amorphous and crystalline valganciclovir for the treatment of herpes viruses.  As such, the Court held that the '721 Patent does not claim more than the invention made or disclosed.


Apotex alleged in its Notice of Allegation that its valganciclovir hydrochloride tablets are amorphous only.  Since the court construed the claims of the '721 Patent to include both amorphous and crystalline valganciclovir, the court held that there was no dispute that Apotex would infringe all valid claims but one which is directed to crystalline valganciclovir only.

Link to decision

Hoffmann-La Roche Limited v. Apotex Inc., 2013 FC 718

Norton Rose Fulbright Canada LLP

Norton Rose Fulbright is a global legal practice. We provide the world's pre-eminent corporations and financial institutions with a full business law service. We have more than 3800 lawyers based in over 50 cities across Europe, the United States, Canada, Latin America, Asia, Australia, Africa, the Middle East and Central Asia.

Recognized for our industry focus, we are strong across all the key industry sectors: financial institutions; energy; infrastructure, mining and commodities; transport; technology and innovation; and life sciences and healthcare.

Wherever we are, we operate in accordance with our global business principles of quality, unity and integrity. We aim to provide the highest possible standard of legal service in each of our offices and to maintain that level of quality at every point of contact.

Norton Rose Fulbright LLP, Norton Rose Fulbright Australia, Norton Rose Fulbright Canada LLP, Norton Rose Fulbright South Africa (incorporated as Deneys Reitz Inc) and Fulbright & Jaworski LLP, each of which is a separate legal entity, are members ('the Norton Rose Fulbright members') of Norton Rose Fulbright Verein, a Swiss Verein. Norton Rose Fulbright Verein helps coordinate the activities of the Norton Rose Fulbright members but does not itself provide legal services to clients.

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.

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.