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Federal Court of Appeal Finds Sanofi’s Plavix Patent Valid and Infringed

August 1, 2013

By Patricia Folkins and Andrea Berenbaum

In Sanofi-Aventis v Apotex Inc, the Federal Court of Appeal1 (FCA) concluded that the Federal Court erred in its judgment (reported here), that Sanofi’s Canadian Patent No. 1,336,777 (the ‘777 Patent) was invalid and consequently allowed Sanofi’s action for infringement. This decision is of particular interest for its comments on the promise of the patent, an important but controversial aspect of the utility analysis in Canada.


The ‘777 Patent is a selection patent. It relates to the active and less toxic enantiomer of a racemate2 known as PCR 4099 which falls within a large genus of racemates claimed in Sanofi’s Canadian Patent No. 1,194,875 (the ‘875 Patent). The bisulfate salt of the enantiomer of the ‘777 Patent is the active ingredient in the anticoagulant drug PlavixTM.

Apotex had previously sought marketing authorization from Health Canada for a generic version of clopidogrel. Sanofi responded by bringing an application under the Patented Medicines (Notice of Compliance) Regulations, a case which ultimately ended up before the Supreme Court of Canada (SCC). In Apotex Inc v Sanofi-Synthelabo Canada Inc (“Plavix”), the SCC found that Apotex’s allegations that the ‘777 Patent was invalid for anticipation, obviousness and double patenting were not justified.

Apotex subsequently commenced an action in the Federal Court seeking a declaration that the ‘777 Patent was invalid3. The Federal Court found that the ‘777 Patent was invalid because the utility of the invention had neither been demonstrated nor soundly predicted as of the filing date of the patent application. A determinative factor in the utility analysis was the Federal Court’s conclusion that the ‘777 Patent promises the use of the invention in humans. This conclusion was reached using inferences based on the wording of the ‘777 Patent as well as the fact that the genus ‘875 Patent explicitly mentions use in humans. The Federal Court further went on to consider obviousness, and also found the ‘777 Patent invalid on this ground.

The FCA Decision

The Canadian courts, including the Federal Court in the present case, have been citing a passage from the FCA decision in Olanzapine for the role of the promise of the patent in a utility analysis. This passage provides that where the patent specification does not promise a specific result, no particular level of utility is required and a mere scintilla of utility will suffice but where the specification sets out an explicit promise, utility will be measured against that promise and the question is whether the invention does what the patent promises it will do. In the present case, the FCA clarified that not every patent contains an explicit promise of a specific result as there is generally no obligation on an inventor to disclose the utility of an invention in a patent. On the other hand, selection patents such as the ‘777 Patent must set out an explicit promise because of the requirement that both the novelty of the selection and its utility (the advantage secured or the disadvantage avoided by the selection) must be described in the patent.

This decision appears to hold that the mere scintilla standard should be applied unless a skilled person would understand the specification to contain an explicit promise of a specific result. While an inventor who promises more for his invention than required can render his patent invalid by a self-inflicted wound, here the FCA held that the Federal Court erred “in reading into the ‘777 Patent a promise for use in humans on the basis of inferences, in the absence of language at least as clear and unambiguous as that used to establish the advantages of the selection over the compounds of the genus patent.”

The FCA also held that the Federal Court erred in holding that, because the ‘875 Patent contained a reference to use in humans, the ‘777 Patent would fail as a selection patent unless an explicit promise for use in humans was also read into it. First, the FCA affirmed a long line of case law holding that is improper to construe a patent with an eye to its validity. Further, the FCA held that it is sufficient that the unexpected advantage of a selection patent is a new and useful improvement on some aspect of the invention described in the genus patent; it need not be an improvement on every aspect.

With respect to obviousness, the FCA held that the Federal Court again erred in holding that the invention was obvious based on the fact that the resolution of the racemate PCR 4099 was obvious to try. It held that the focus of the obviousness analysis in Plavix was not the difficulty in separating the racemates covered by the ‘875 Patent but rather the unknown properties of the resulting enantiomers, and it was the lack of knowledge as to these properties that led the SCC to hold that it was not self-evident that what was being tried ought to work. As the results to be obtained were unknown, the FCA held that the distance between the common general knowledge and the inventive concept of the ‘777 Patent could not be bridged by routine experimentation.

Summary and Outlook

In the present case, the FCA stressed that Courts should not strive to find ways to defeat otherwise valid patents. While this suggests that the Canadian courts may be less motivated to read an explicit promise into a patent based on inferences, it remains important (as noted here) to consider the language used in an application to describe a promised utility to ensure it does not elevate the utility beyond that which is supported. The decision also confirms that selection patents must disclose the advantage secured or disadvantage avoided by the selection but clarifies that it is sufficient that this be a new and useful improvement on some aspect of the invention described in the genus patent; not every aspect. Apotex may still seek leave to appeal this decision to the SCC.


1Reasons for judgment were provided by Pelletier JA, concurred in by Noël JA. Gauthier JA agreed that the appeal should be allowed for the reasons given by Pelletier JA but in concurring reasons commented further on certain issues in respect of utility and obviousness.
2A racemate is a mixture of equal amounts of two compounds known as enantiomers which differ in structure in that they are mirror images of each other.
3Sanofi also brought an action alleging Apotex infringed this patent. The two actions were consolidated, and the Federal Court held that the ‘777 Patent would have been infringed if it were not invalid.

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Patricia Folkins Patricia Folkins
B.Sc. (Honours Chem.), Ph.D. (Org. Chem.)
905.817.6101  email Patricia Folkins