State of the Art for an Obviousness Attack Includes Only Art Discoverable in a Reasonably Diligent Search

Novartis Pharmaceuticals Canada Inc v Teva Canada Ltd 2015 FC 770 O'Reilly J
            2,255,951 / deferasirox / EXJADE

O’Reilly J’s decision in Novartis v Teva / deferasirox does not break wholly new legal ground, but it does develop several interesting points regarding the state of the art in obviousness, Viagra-style insufficiency, and the promise of the patent. I will deal with these issues in separate posts.

The ‘951 patent relates to iron chelators, which are used to treat disorders caused by excess iron in the body [7]. Iron chelators were known in the prior art, but the most effective could not be administered orally, and others were toxic or insufficiently effective [9]. The problem facing the inventors was therefore to find an effective iron chelator that could be orally administered. Two classes of compounds are disclosed in the patent: Formula I compounds were previously known, and the relevant claims were to their use for treatment of diseases involving excess iron in humans, while Formula II compounds were novel, and they were claimed both as compounds and for the use in treatment of iron excess diseases [14]. Deferasirox, the active ingredient in EXJADE, is a Formula II compound and so is covered by both use and compound claims.

The obviousness attack turned primarily on the facts, but a pure question of law was raised as to what constitutes the prior art for the purposes of an obviousness attack. O’Reilly J held that there was considerable doubt as to whether some of the sources formed part of the relevant prior art for the purposes of an obviousness attack because they would not have been located by a skilled person conducting a reasonably diligent search. But section 28.3 of the Act provides that an invention must not be obvious having regard to information that “became available to the public” in Canada or elsewhere before the relevant date. This is exactly the same language as used in the novelty provision, s 28.2. Citing Barrigar’s, Canadian Patent Act Annotated, at PA-341, Teva argued that this means that the old requirement that only reasonably discoverable information can be used in an obviousness attack is no longer the law, and the prior art for obviousness and novelty purposes should be the same [53]. 

Teva has a good argument based on the text of the Act, but I have argued that “contextual and purposive considerations imply that s. 28.3 was not intended to change the law, and the state of the art remains limited to information that is reasonably discoverable”: What is the State of the Art for the Purpose of an Obviousness Attack?, (2012) 27 CIPR 385 at 394. I went on to note that “the argument based on the text of the provision is sufficiently strong that case law directly addressing the question will be needed before the point can be considered settled.” In this case, O’Reilly J stated that “there is case law applying the usual ‘reasonably diligent search’ criterion even after the enactment of s 28.3. I see no reason to take a different approach here” [53]. While O’Reilly J is right to say that there was prior case law using the traditional criterion, the question of whether s 28.3 had modified the law was not raised in those decisions. O’Reilly J’s considered holding is therefore a significant development on this point of law. Strictly, however, his holding was obiter, since he held that the invention was not obvious even if Teva’s interpretation was correct [54]. With that said, I believe that O’Reilly J's decision is the first to directly address this point, and it certainly reinforces the view that properly interpreted, s 28.3 did not change the law.