The Federal Court of Appeal released its decision in the appeal from the successful patent impeachment action by SNF challenging the validity of a Ciba Specialty Chemicals Water Treatments patent related to a process of employing flocculants to recycle water from dispersed particulate matter in the mining industry. At trial, Justice Phelan held that Canadian Patent 2,515,581 was invalid for obviousness (see our previous post here).
On appeal, the Court only dealt with the issue of obviousness, holding that while the trial Judge had come to the right conclusion, he had erred in the articulation of the Windsurfing/Pozzoli obviousness framework, including by relying on a paraphrase of this framework from the Federal Court’s decision in Mylan tadalafil:
 In the decision before us, the Federal Court did not refer to the Supreme Court’s elaboration of the Windsurfing/Pozzoli framework but relied instead on the Federal Court’s summary of the latter in Eli Lilly Canada Inc. v. Mylan Pharmaceuticals ULC, 2015 FC 125 at paragraph 158, 130 C.P.R. (4th) 116:
1) Identify the notional “person skilled in the art” and the relevant common general knowledge of that person;
2) Identify the inventive concept claimed in the patent;
3) Identify the differences between the common general knowledge and the inventive concept;
4) Do those differences require a degree of invention, or are they more or less self-evident? Reasons, at paragraph 182.
 This formulation introduces an error in the framework when it substitutes “the common general knowledge” for “the matter cited as forming part of the ‘state of the art’”. The error is that, at step 3, the inventive concept is not to be compared to the common general knowledge but to the prior art.
The Court of Appeal clarified that the common general knowledge is only part of that state of the art and that the proper comparison in step 3, as adopted by the Supreme Court of Canada in Apotex clopidogrel, is the inventive concept (or claims as construed) to the prior art relied upon by the person alleging obviousness. To the extent that language in the Court of Appeal’s decision in Teva atazanavir (see our previous posts here and here) suggested otherwise, this was a misstatement.
The Court of Appeal further held that the trial Judge’s paraphrasing step 4 of the Windsurfing/Pozzoli test introduced another error, or at least an oversimplification. The relevant analysis goes beyond whether the differences in the prior art and the inventive concept (or claims as construed) are self evident, as the skilled person may also rely on their common general knowledge in this step of the test.
The Court held that the trial Judge’s formulation of the inventive concept improperly appears to have been arrived at by first defining the invention and then subtracting the common general knowledge. This approach conflates steps 2 and 3 of the Windsurfing/Pozzoli framework. Rather, the Court of Appeal again looked to English Court of Appeal’s decision in Pozzoli for guidance on how to identify the inventive concept:
It is the inventive concept of the claim in question which must be considered, not some generalised concept to be derived from the specification as a whole. Different claims can, and generally will, have different inventive concepts. The first stage of identification of the concept is likely to be a question of construction: what does the claim mean? It might be thought there is no second stage – the concept is what the claim covers and that is that. But that is too wooden and not what courts, applying Windsurfing stage one, have done. It is too wooden because if one merely construes the claim one does not distinguish between portions which matter and portions which, although limitations on the ambit of the claim, do not. One is trying to identify the essence of the claim in this exercise.
The Court of Appeal, following the English decisions in Pozzoli and Connor v. Angiotech, held that where there is a dispute as to the inventive concept, it is a unhelpful distraction, and should be avoided in favour of claim construction:
 There may be cases in which the inventive concept can be grasped without difficulty but it appears to me that because “inventive concept” remains undefined, the search for it has brought considerable confusion into the law of obviousness. That uncertainty can be reduced by simply avoiding the inventive concept altogether and pursuing the alternate course of construing the claim. Until such time as the Supreme Court is able to develop a workable definition of the inventive concept, that appears to me to be a more useful use of the parties’ and the Federal Court’s time than arguing about a distraction or engaging in an unnecessary satellite debate.
Applying this approach, the Court of Appeal construed claim 1 and held it to be obvious in light of the Gallagher reference, holding:
 As can be seen, much of what is claimed in Claim 1 of the ‘581 patent is found in the Gallagher patent. In particular, the Gallagher patent teaches the treatment of a solution of dispersed particulate matter by the in-line addition of water-soluble polymer. The treated solution maintains its fluidity while being pumped but solidifies or rigidifies upon deposition.
[95 ] ….A Skilled Person, using their common general knowledge, would be able to bridge the difference between the claim as construed and the cited prior art (the Gallagher patent). The Federal Court found that the common general knowledge included the knowledge that flocculation was dose-dependent: Reasons at paragraph 185. It requires no inventiveness to go from that knowledge to the knowledge that increasing the dose beyond conventional dosage would eventually produce the desired results. As a result, the invention claimed in the ‘581 patent is obvious.
Justice Woods, in concurring reasons, held that the effects of section 28.3 of the Patent Act on the determination of obviousness should be left for another day.
A copy of the Court of Appeal’s decision may be found here.