Intellectual property bulletin: torys successfully defends patents for viagra® and lipitor® (ipb2007-4) - october 9, 2007

Torys Successfully Defends Patents for Viagra® and Lipitor®
Torys lawyers have successfully represented Pfizer in two cases before the Federal Court of Canada, defending allegations against patents covering Viagra and Lipitor. The Viagra® Decision: If it’s only worth a try, it’s not obvious; Swiss-type claims are for the use of
the medicine

In the Viagra case, the patent covered the use of sildenafil (the active ingredient in Viagra) for the treatment of erectile dysfunction. Apotex had alleged that the claims were invalid as being obvious, anticipated, broader than the invention, and were not claims to the use of the medicine. Corresponding patents in the United Kingdom and other jurisdictions had been found invalid on the basis of obviousness, and the Canadian case turned on this very issue. Justice Mosley rejected the obviousness attack. He reinforced the value of inventions to society and reaffirmed that obviousness is a difficult test to satisfy. He considered all the relevant factors, including the teaching of the prior art as well as secondary indicia such as the surprise that accompanied sildenafil’s launch, its subsequent wide use and acceptance, and commercial success. The Court concluded that the most that could be said was that the prior art suggested that the class of drugs to which sildenafil belonged might have benefit in treating impotence (i.e., that the class of compounds might be “worth a try”). Justice Mosley recognized that inventions do not come out of the blue, but are based on the body of work in the prior art and on incremental progress; that is, they are part “deductive science and part luck,” a standard consistent with Canadian case law, which holds that invention can arise equally through empirical research or lucky chance and inspiration. Under Canadian law, a solution to a problem that might be “worth a try” is not obvious. This is particularly so when, as in this case, all the experts who were working in closely related fields could not answer the question, “If it was so obvious, why didn’t you do it?” Another notable aspect of Justice Mosley’s decision is the way he treated the so-called Swiss-type claims. While typical-use claims are often drafted to read “the use of compound A for the treatment of condition B,” Swiss-type claims read “the use of compound A for the manufacture of a medicament for the treatment of condition B.” Whether or not these are “claims for the use of the medicine,” which entitles a patentee to assert these claims in Patented Medicines (Notice of Compliance) Regulations litigation, had been an unsettled question under Canadian law. Justice Mosley had no difficulty concluding that, “taking a practical approach to [claim] interpretation,” the Swiss-type claims were “claims for the use of the medicine” and entitled to the benefit of the protection of the Regulations. The other validity allegations were also found not to be justified. As a result, Apotex is prohibited from obtaining marketing approval for its generic version of Viagra until after the patent expires in 2014. The decision is subject to appeal. Lipitor®: Use of patented intermediate in India infringes Canadian patent
In the Lipitor case, Ranbaxy Laboratories had alleged non-infringement of the patent covering crystal Form I of atorvastatin calcium. The dispute centred on the intermediates used in the process to 2007 by Torys LLP. All rights reserved. Torys Successfully Defends Patents for Viagra® and Lipitor®
make Ranbaxy’s active pharmaceutical ingredient. Justice Snider held that the intermediates included all of the elements of the claims. Ranbaxy argued, however, that its product would be made in India and therefore the use of the patented intermediates would not infringe the Canadian patent. The issue turned on the application of the so-called Saccharin Doctrine. In the Saccharin case (a U.K. case), the defendant made saccharin in a foreign country, employing a certain process and intermediate. Saccharin Corp. owned a U.K. patent covering the process to make the intermediate. The defendant made the intermediate using the patented process, then converted the intermediate to saccharin and imported the saccharin into the United Kingdom. Even though the process was carried out entirely outside the United Kingdom, the Court held that the patentee is deprived of some part of the invention when the saccharin (made using an infringing process) is imported and that the defendant had infringed the patent. In the Lipitor case, Ranbaxy argued that the Saccharin Doctrine did not apply and that its application would require an “extension of a legal principle.” Ranbaxy argued that the Saccharin Doctrine is limited to process claims. It went on to argue that, as the intermediate in this case was covered by a product claim and not a process claim, there could be no infringement. Justice Snider rejected this argument and upheld the application of the Saccharin Doctrine in Canada, finding that there was no reason to limit the application of the Saccharin Doctrine to process claims. She concluded that the focus of the analysis was on whether the patentee had been deprived of any part of the invention. This decision reaffirms the application of the Saccharin Doctrine in Canada. Ranbaxy is prohibited from obtaining marketing approval for its generic version of Lipitor until the expiry of the patent in 2016. The decision is subject to appeal. As a result of this decision, pharmaceutical manufacturers, particularly generic drug manufacturers, will not be allowed to avoid infringement of Canadian patents by using patented intermediates or patented processes offshore, then importing the active ingredient or finished product to Canada. Like the Viagra decision, the Lipitor decision is further recognition of the importance of inventions. Andrew Bernstein
Kamleh Nicola
Andrew Shaughnessy
Peter Wilcox
[email protected] [email protected] [email protected] [email protected]
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2007 by Torys LLP. All rights reserved.


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