Federal Court of Appeal Overturns Trial Decision, Affirming Validity of Selection Patent in Plavix® Case

On July 24th, the Federal Court of Appeal released its decision in Sanofi-Aventis v. Apotex Inc.,¹ overturning the lower court’s conclusions on lack of utility and obviousness in Apotex’s impeachment action.

The patent at issue is the 777 Patent claiming clopidogrel bisulfate, which is marketed by Sanofi-Aventis (Sanofi) as Plavix^®, an anticoagulant therapy. Clopidogrel is one enantiomer of a racemic mixture disclosed in a prior genus patent, and as such, the 777 Patent was properly described as a "selection patent."

Procedural History

The 777 Patent had previously been litigated by the parties in an application under the PM(NOC) Regulations. In that case, the Court held that Apotex’s allegations of invalidity of the 777 Patent (including anticipation and obviousness) were not justified. That decision was upheld by the Federal Court of Appeal and the Supreme Court of Canada, where the Court set out new tests for obviousness and anticipation, including in the context of selection patents.

After the Supreme Court’s decision, Apotex brought an impeachment action, alleging that the 777 Patent was invalid on a number of grounds, including obviousness and lack of utility. The trial judge found for Apotex on both of those grounds, holding that: (1) the patent was invalid because the inventors promised, but could not soundly predict, improved properties in humans; and (2) that the invention was obvious. Sanofi appealed these findings.

No "Promise" of Utility in Humans

The Federal Court of Appeal scrutinized the trial judge’s analysis of the "promise of the patent," providing clarity and guidance on the interpretation of this key—and uniquely Canadian—concept related to the requirement of utility.

The trial judge held that the "promise of the patent" was the use of the compound to treat humans, despite the fact that the patent made no express reference to human treatment. To support what he referred to as an "explicit promise," the trial judge relied on certain aspects of and language in the patent specification, such as the fact that the diseases and conditions referred to in the patent were human diseases, that the dosing ranges referred to in the patent corresponded to doses that could be administered to a human, and that the invention was described as a "medicine."

The Court of Appeal reversed on this point. It held that the trial judge erred in law by reading in a promise for use in humans on the basis of "equivocal" inferences without clear and unambiguous language in the specification (such as that used to describe the advantages of clopidogrel over the compounds of the genus patent). The Court also emphasized the distinction between potential use in humans (which was obviously of ultimate interest to the pharmaceutical company) and an explicit promise in the patent that that result would be achieved. As the Court reiterated, "a goal is not necessarily a promise."

In her concurring decision, Justice Gauthier noted that patents often include statements relating to practical utility for reasons that have little to do with any promise of a certain result. She provided an example of patents based on European applications, which often contain statements to support industrial application (which is not a requirement in Canada). Justice Gauthier cautioned, "one must be careful not to treat each reference to a practical purpose as a promise of a specific result." Put another way, not every statement in a patent that relates to use is necessarily part of the "promised utility."

This is an important decision on the subject of the promise of the patent. Lack of utility has become a very common challenge to patents, and the question of promise is a threshold issue in each case. There are a few instances of courts finding that patents for basic compounds contain a promise that these compounds will be useful in humans, typically on the basis of the type of language used in the 777 Patent. This decision should mark the end of courts finding an "implied promise of human use," which will come as a welcome relief to the pharmaceutical industry.

Not "Obvious to Try" to Resolve an Enantiomer with Unknown Properties

The trial judge also held that the 777 Patent was invalid on the basis of obviousness, finding that the racemic mixture containing clopidogrel was previously disclosed, that the possible methods of separation of the isomers were known in the art, and there was a strong motivation to resolve the isomers. Based on these factors, he concluded that the invention was obvious to try.

In overturning the trial judge's decision, the Court of Appeal found that it could not be reconciled with the Supreme Court’s decision, which specifically rejected the allegation that the claimed invention was obvious to try. The Supreme Court’s analysis relied heavily on the fact that a skilled person would not have known the properties of each of the enantiomers comprising the previously disclosed racemic compounds. The Court of Appeal held that, although the methods for resolving the isomers and the existence of the racemic compound were known, the skilled person could not know the properties of each isomer once separated. For this reason, it was not "obvious to try" to resolve the enantiomers to obtain a compound with the advantageous properties of clopidogrel. The Court of Appeal held that the trial judge erred in failing to reach this result in his application of the test for obviousness.

This finding on obviousness is important because the Court of Appeal affirmed that, in considering obviousness, the key issue is if the invention (in this case, the selected species and its advantageous properties) would have been more or less self-evident. The fact that a skilled person would know how to resolve the racemate or perform experiments to find out the properties of a given isomer does not make an invention obvious. This affirms the relatively strict approach to obviousness that the Court of Appeal has employed since the Supreme Court re-articulated the obviousness test in the first Plavix decision.

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¹ 2013 FCA 186.