On April 11, 2017 the Federal Court of Appeal released its decision in BMS’ appeal of a Judgment dismissing a prohibition application relating the drug atazanavir and Canadian Patent No. 2,317,736. The decision significantly clarifies many aspects of the law of obviousness after the Supreme Court of Canada’s seminal 2008 decision in Plavix 1.
The Applications Judge below held that the inventive concept of the claims of the 736 Patent was a specific anhydrous crystalline form of atazanavir bisulfate having increased bioavailability over the free base and increased solid state stability (see the Reasons below, here). While it was agreed that the crystallinity and the stability of the claimed salt could not be predicted in advance, Justice Mactavish nevertheless held that it was obvious to try to make the claimed salt in order to increase the bioavailability of atazanavir.
On appeal, BMS argued that Justice Mactavish had misapplied the “obvious to try” test because the inability to predict all aspects of the inventive concept was fatal to any finding of obviousness, as reflected in the following paragraphs from BMS’ written argument:
77. The ‘obvious to try’ test involves a hypothetical cognitive exercise done before the claimed invention is made, and without the benefit of hindsight. To use the words of the Supreme Court in Plavix #1, it requires a finding, prospectively, that it would have been “more or less self-evident to try to obtain the invention”.
78. To be satisfied in this case, the legal standard requires the prospective finding (which was never made) that it would have been more or less self-evident that a routine salt screen would generate Type-I atazanavir bisulfate, and that it would have the properties the Applications Judge found were included in the inventive concept.
The Court of Appeal after a substantive review of the decisions of the Supreme Court of Canada in Plavix 1 and its own subsequent decision in Plavix 2, reaffirmed that the leading authority on obviousness remains Plavix 1, cautioning that one should not read into Plavix 2 things that have no foundation in Plavix 1. The Court of Appeal then concluded that the rigid application of the ““obvious to try” test advanced by BMS was antithetical to the flexible approach to obviousness:
 As a result, I am of the view that a categorical approach to obviousness, such as that advocated by BMS, is inappropriate. The elaboration of a hard and fast rule that obviousness cannot be shown unless all the elements of the inventive concept can be predicted with a high degree of certainty is the antithesis of the approach to obviousness that the Supreme Court favoured in Plavix 1. Not every case requires recourse to the “obvious to try” test and not every recourse to the “obvious to try” test must follow in the furrow of the preceding application of that test.
The Test for Obviousness
Following Plavix 1, the Court of Appeal reaffirmed that in the end what matters is the difference between what is claimed and the prior art. An invention is obvious if the distance between the prior art and the invention (or alternatively the “inventive concept” or “solution taught by the patent” or “what is claimed”) can be bridged by the skilled person without invention. The introduction of “inventive concept” into the Canadian law of obviousness in Plavix 1 did not result in any substantive change in the law or in the definition of obviousness:
 It may be helpful to keep in mind that the obviousness analysis asks whether the distance between two points in the development of the art can be bridged by the Skilled Person using only the common general knowledge available to such a person. If so, it is obvious. The first of those points is the state of the prior art at the relevant date. References in the jurisprudence to “the inventive concept”, “the solution taught by the patent”, “what is claimed” or simply “the invention” are attempts to define the second point.
 Prior to Plavix 1, the jurisprudence followed Beloit and treated the second point as “the solution taught by the patent” which was often treated as synonymous with “what is claimed in the patent” or “the invention”: Proctor & Gamble Pharmaceuticals Canada Inc. v. Canada (Minister of Health), 2004 FCA 393,  2 F.C.R. 269 at para. 47, Pfizer Canada Inc. v. Canada (Health), 2007 FCA 209, 366 N.R. 347 at para. 133, Novopharm Limited v. Janssen-Ortho Inc., 2007 FCA 217, 366 N.R. 290 at para. 25. The question is whether the “inventive concept” was intended to redefine the second point as it was understood to be prior to Plavix 1. I note that in the passage from Pozzoli quoted above, the English Court of Appeal did not consider the “inventive concept” to have changed anything of substance. If the parties could not agree on it, it could be forgotten. It went on to say at paragraph 19 of its reasons: “In the end what matters is/are the difference(s) between what is claimed and the prior art.” This is essentially the state of Canadian law prior to Plavix 1.
 Is it the case that changing one of the two points I referred to earlier amounts to changing the definition of obviousness? Given that obviousness is concerned with whether bridging the difference between the prior art and a second point requires inventiveness, changing the second point will affect the difficulty of bridging that difference, therefore making inventiveness more or less likely. If that is so, is it reasonable to conclude that the Supreme Court intended to change the definition of the obviousness analysis when it adopted, without commentary, the Windsurfing/Pozzoli framework? Is it likely that the Supreme Court, having taken great care in modifying the test for obviousness, would, without saying so, change the definition of obviousness?
 My inclination is to believe that the Supreme Court does not change substantive law by implication, particularly when it has shown a cautious approach to change in the same context: see Apotex Inc. v. Eli Lilly Canada Inc., 2016 FCA 267, 142 C.P.R. (4th) 171 at para. 37.
In dismissing BMS’ appeal, the Court of Appeal held that the Applications Judge had not erred in the application of the “obvious to try” test, but had erred by finding that the anhydrous nature and physical stability of the salt formed part of the inventive concept of the 736 Patent. This error, however, did not lead the Court of Appeal to overturn the judgment.
A more fulsome discussion of Court of Appeal’s analysis of the “inventive concept” and the place that term has in patent law can be found in the companion post, here.
A copy of the Court of Appeal’s Reasons may be found here.
Teva was represented in the appeal by Aitken Klee partners Jon Stainsby and Scott Beeser.