The judgment , authored by Justice Marshall Rothstein, upheld Canadian pharmaceutical company Sanofi-Aventis's patent for Plavix (clopidogrel bisulfate), a popular blood clot inhibitor, rejecting generic drug company Apotex's claims that the patent was invalid for anticipation, obviousness and double patenting.
In 2003, Apotex served a Notice of Allegation on Sanofi-Aventis to obtain a Notice of Compliance from the Minister of Health to market its generic version of Plavix before Sanofi's patent had expired.
Apotex claimed that the Plavix patent was invalid on the grounds of anticipation, obviousness and double patenting, since the compound on which the patent was based had been disclosed in an earlier patent, also owned by Sanofi-Aventis.
Sanofi-Aventis successfully blocked the issuance of the Notice of Compliance and the Federal Court of Appeal upheld the decision. The Supreme Court agreed to hear Apotex's appeal, and on Thursday it upheld the Plavix patent.
The ruling is significant since it is the first time the Supreme Court has considered whether selection patents - or patents based on a limited class of compound(s) selected from a broader class covered by an existing patent - should continue to be recognised under Canada's Patent Act.
The Court also articulated its views on the subjects of anticipation and obviousness, principles that extend to all patents.
First, the Court said that, when determining whether or not an invention has been anticipated, a two-step approach should be followed, in which the requirements of "prior disclosure" and "enablement" are considered separately.
The doctrine of enablement - which asserts that, in addition to being previously disclosed in another patent, the prior art in question must also make it easy for one of ordinary skill in the art to create the new invention without excessive experimentation or trial and error - was not previously part of Canadian patent law.
Based on this new standard, the Court found that there was no prior disclosure in the case of the Plavix patent, since the genus patent did not teach the "special advantages" of the new invention. Furthermore, the Court said that, even if prior disclosure had been found, the Plavix patent would have survived the enablement determination, since "the identification of clopidrogel, its bisulfate salt and their advantageous properties required extensive investigation over a period of months".
On the question of obviousness, the Court applied a four-step approach, which most significantly clarified the principle of whether or not an invention is "obvious to try".
The court said: "[A] court must consider whether, viewed without any knowledge of the alleged invention as claimed, those differences constitute steps which would have been obvious to the person skilled in the art or whether they require any degree of inventiveness."
The judgment went on to say that "there must be evidence to convince a judge on a balance of probabilities that it was more or less self-evident to try to obtain the invention" and that "mere possibility that something might turn up is not enough".
Finally, the Court reaffirmed the validity of selection patents when it said that "selection patents encourage improvements over the subject matter of the original genus patent because that selection does something better than or different from what was claimed in the genus patent".
Peter Brenders, president and CEO of BIOTECanada, said in a statement: "The decision to uphold the validity of selection patents will strengthen the certainty of our patent system and assist Canadian biotechnology firms in attracting international investment during these difficult times."
Patrick Kierans of Ogilvy Renault, who represented Canada's Research-Based Companies (Rx&D), one of the interveners in the case, said that the decision has brought much-needed clarity to Canadian patent law: "We had a bunch of decisions coming out of the Patented Medicines Notice of Compliance (PMNOC) regulations that had started to go all over the place [on the issue of obviousness]."
Kierans said that, since much of Canadian patent law has been formed on the basis of decisions made during PMNOC proceedings, where no appeal is allowed: "A lot of the law in the pharmaceutical patent field was being distorted and there was no opportunity to straighten it out. We were all very concerned that it was becoming disjointed."
A spokesman for the Canadian Generic Pharmaceutical Association (CGPA), another intervener in the case, told Managing IP that, though disappointed with the decision, certain aspects of the judgment could be good for generic drug companies as well: "While the Supreme Court dismissed the appeal, the unanimous reasons provided by the Court change the law of both anticipation and obviousness, making the legal tests, particularly for obviousness, more flexible and, possibly, easier for generic pharmaceutical manufacturers to meet in other cases."
Kierans added: "Where we are today [after this ruling], patent law has been strengthened for patentees."
