Wednesday, April 19, 2017

Important Course Correction on Inventive Concept

Bristol-Myers Squibb Canada Co v Teva Canada Ltd 2017 FCA 76 Pelletier JA: Near, Rennie JJA aff’g 2016 FC 580 Mactavish J
            2,317,736 /atazanavir / REYATAZ / NOC

The FCA’s Atazanavir decision is a welcome course correction dealing with the role of the inventive concept in the obviousness analysis. Since Sanofi / Plavix 2008 SCC 61, [67], endorsed the four-step Windsurfing/ Pozzoli framework, identifying the “inventive concept” in the second step has become an increasingly lengthy and contested aspect of an obviousness attack. The FCA’s Atazanavir decision has now pressed the reset button on this approach, emphasizing that Sanofi did not effect any radical change in the law on this point. This important – and short – decision is essential reading on the issue of obviousness.

Atazanavir is used in the treatment of HIV/AIDS. Claim 20 of BMS’s patent 2,250,840 claimed atazanavir or a salt thereof [FC 53]. The 840 patent was held valid by Mactavish J and this was not appealed. The 840 patent was part of the state of the art with respect to BMS’s 736 patent, which claimed the bisulfate salt of atazanavir [FC 273].

Mactavish J found that the inventive concept of the 736 patent included: (1) improved oral bioavailability of the bisulfate over the free base; (2) crystallinity; and (3) stability [12], [FC 446]. She held that improved bioavailability was obvious. The crystalline form and stability were advantageous and could not have been predicted in advance [FC 506], but these properties of atazanavir bisulfate were easily discovered using routine techniques, and consequently “did not add anything inventive” [FC 507], [26]. She therefore concluded that atazanavir bisulfate was obvious [FC 509]. As discussed here, my view is that holding was correct on the facts as found by Mactavish J.

BMS appealed, and the key question was:

whether the Federal Court erred when it found that the development of Type-I atazanavir bisulfate was obvious in spite of the fact that only one of the three elements of the inventive concept, improved bioavailability over the free base of atazanavir, was predictable and the uncontradicted evidence was that the other two elements, crystallinity and stability, were not. [32]

This gets at the heart of a trend that has developed since Sanofi, 2008 SCC 61, [67], in which the SCC endorsed the four-step Windsurfing / Pozzoli approach to the obviousness determination. The second step of this inquiry is to “Identify the inventive concept of the claim in question or if that cannot readily be done, construe it.” Since then, the definition of the inventive concept has turned into a key battleground on obviousness. The patentee typically tries to multiply the number of attributes of the inventive concept, on the theory that at least one will be non-obvious. If, as per Mactavish J’s holding, an invention can be obvious if only one attribute of the inventive concept is obvious, then this strategy will not work.

The bigger issue is not who might win or lose from a shift in the doctrine, is the fact that defining the “inventive concept” has become a battleground in the first place. This is a problem in itself. As the FCA pointed out, [63] the SCC neglected “the cautionary note struck in Pozzoli [[2007] EWCA Civ 588, [19]] with respect to the inventive concept”:

In some cases the parties cannot agree on what the concept is. If one is not careful such a disagreement can develop into an unnecessary satellite debate. In the end what matters is/are the difference(s) between what is claimed and the prior art. It is those differences which form the "step" to be considered at stage (4). So if a disagreement about the inventive concept of a claim starts getting too involved, the sensible way to proceed is to forget it and simply to work on the features of the claim.

Since the SCC ignored this warning, it is not very surprising that subsequent Canadian courts, until now, have not heeded it either. Instead, pages are often devoted to an involved and technical debate over the inventive concept, and the result not uncommonly turns on that determination.

In the Atazanavir decision, the FCA has pressed the reset button on this approach. The Court undertook a careful review of Sanofi, pointing out that the key innovation was to the endorse the “obvious to try” test from the UK [34], [58], and the Court was otherwise “very cautious about substituting one rigid rule for another” [59]. While the entire analysis is worth reading, here are some key paragraphs (my emphasis):

[65] 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.

I must say that this simple statement does strike me as a helpful way of framing the basic question. The controversial questions – What is the first point? How skilled is the skilled person? What is the second point? – are aspects of this larger question.

            The first of those points is the state of the prior art at the relevant date.

That in itself is uncontroversial. There is some controversy as to what exactly constitutes the “state of the art,” but it is not at issue in this case, which is focused on the “second point.”.

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.

[66] Prior to Plavix 1 [Sanofi], 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”. 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.
[67] 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?

[68] 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
. . .
[75] For the reasons set out above, I find that the “inventive concept” is not materially different from “the solution taught by the patent”.

One key point, then, is that the SCC in Sanofi did not change the “second point.” It endorsed the “obvious to try” test as part of the obviousness analysis, and the Windsurfing/Pozzoli framework provided structure (perhaps not an especially useful structure – [64], [69] – but that is a different matter), but neither of these changes the substance of the test. I agree entirely with the FCA’s analysis in this respect.

What, then, is the “second point”? The various terms, “the invention”, “the inventive concept”, “the solution taught by the patent”, and “what is claimed” are all synonyms for that second point. That was true before Sanofi, and it remains true now. Again, I agree entirely with the FCA’s analysis in this respect, though I would add that this conclusion also has the virtue of being consistent with s 28.3of the Act , which states that “The subject-matter defined by a claim” must not have been obvious. This is not surprising, as s 28.3 is generally understood to have codified the case law at the time of its enactment, which was of course pre-Sanofi.

The net effect then, is to downplay the importance of the “inventive concept” as an independent, technical part of the obviousness analysis, and return to a focus on the overarching question of whether the claimed invention is obvious. While the SCC neglected the “cautionary note” struck in Pozzoli, that does not mean that the caution is not worth heeding. We can’t be too critical of the SCC on this point. As the FCA noted, the SCC was primarily concerned with the obvious-to-try test, and in Sanofi itself, there was no difficulty in identifying the inventive concept [SCC 78], and so the cautionary note was not engaged. And the second step did expressly say “or if [identification of the inventive concept] cannot readily be done, construe it.” The caution was implicit, if not explicit.

This reset is therefore consistent with Sanofi. In my view, it is also highly desirable. The free-standing inventive concept inquiry was getting out of control. On the one hand, if we were to accept that all the properties of a claimed invention had to be non-obvious, as BMS argued in this case, this could lead to claims being wrongly found to be non-obvious on the basis of some extraneous property. So far the courts have largely avoided this problem, as did Mactavish J at first instance in this case (and see here), but the problem is real. Nor is the current approach solely to the benefit of the patentee. It can also lead to a claimed invention being wrongly held invalid, if the inventive concept were wrongly defined: see here. But my main fear is that the search for the inventive concept in the disclosure could lead to the same kind of problem that we have seen with the promise doctrine in the law of utility, where patent validity turns on a subjective parsing of the disclosure.

While the reset is welcome, where does that leave us? The FCA held that Mactavish J had erred in identifying the inventive concept [74], and she should have treated the “inventive concept” as being the same as “the solution taught by the patent” [75]:

Had the Federal Court applied that definition to the facts, it would have found that the inventive concept in this case is atazanavir bisulfate, a salt of atazanavir which is pharmaceutically acceptable because it has equal or better bioavailability than the atazanavir free base.

But why is better bioavailability, and not the crystalline form, or stability, the solution to the problem? I don’t see any explicit discussion leading the FCA to that conclusion. The closest seems to be this statement made in the course of summarizing the FC decision:

[23] As for the question of motivation to find the claimed solution, the Federal Court found that the limited bioavailability of atazanavir would have given the skilled person every reason to try to improve its solubility – and therefore its bioavailability – by making its salts: Reasons at paras. 483, 497.

This suggests that the problem was poor bioavailability, so the solution was improved bioavailabililty, and not stability or crystalline properties.

But the answer is perhaps not so easy. Mactavish J had noted that “A development team of BMS scientists then began research in an effort to discover a form of atazanavir having properties suitable for an oral pharmaceutical dosage form, including improved oral bioavailability” [FC 268], implying that bioavailability was only one desirable property. And at [484], just after the paragraph cited by the FCA, she noted that “The Type-I atazanavir bisulfate salt also had better bioavailability than the free base, and was in an anhydrous, non-hygroscopic crystalline form. All of these properties were advantageous in preparing oral formulations of atazanavir, and none had been seen in the prior art” (my emphasis). Both these statements suggest that the problem was not solely to improve bioavailability, but more broadly to discover a form of of atazanavir suitable for an oral pharmaceutical dosage form, and all of the properties she identified were part of that more general solution, even if bioavailability may have been the most pressing problem.

This is not to say that bioavailability was not the problem, but only that it is not clear, from this decision at least, how the problem should be identified. If the inquiry shifts from determining “the inventive concept,” to determining “the problem to which the invention is a solution,” then this may not be much of a change. I have suggested elsewhere that an objective problem-and-solution approach, such as is used by the EPO, might be helpful. As the FCA has noted in this case, the idea of the target of the obviousness inquiry as being a solution to a problem has a long history in Canadian jurisprudence. The EPO approach, in my view, just elaborates on how to identify the problem. I would also note that the phrase “the solution taught by the patent,” which derives from Beloit 8 CPR(3d) 289, 294 (FCA) [35], does not in itself imply a subjective approach, in which the problem is that which is identified in the patent itself, in contrast to the objective approach used by the EPO. The phrase “a solution to the problem the patent addresses,” used in Sanofi [SCC 59], is similarly ambiguous.

My point here is not to criticize the FCA, but simply to point out that some unresolved questions remain. It wasn’t necessary for the FCA to resolve these points in this case. The claimed invention was atazanavir bisulfate. Mactavish J held, and the FCA emphasized, that a skilled person “would quickly, easily, directly and relatively inexpensively, in light of the prior art and common general knowledge” come to Type-I atazanavir bisulfate salt [80]. That is true whether the “problem” is a form suitable for an oral pharmaceutical dosage form, or improved bioavailability more specifically. It was “more or less self-evident” that a salt screen would work [82]. The FCA focused on bioavailability, because that was clearly one important property in developing an oral dosage form, and the problem of improving bioavailability was in itself enough of a motivator to lead, without difficulty, to lead to atazanavir bisulfate.

More broadly, the FCA emphasized that the SCC in Sanofi was of the view that “rigid rules are inappropriate unless mandated by statute,” [58], the Court “showed itself to be very cautious about substituting one rigid rule for another” [59], and the Court favoured “an expansive and flexible approach” to the obviousness inquiry [61]. And in Sanofi [59], quoted by the FCA, [37], the SCC referred to the “solution to the problem the patent addresses” as only one factor that is relevant to the obviousness inquiry. Consequently, the FCA cannot be taken to be substituting one rigid rule for another. The Court clearly intended to put an end to the “unnecessary satellite debate” over the inventive concept; it cannot have intended to substitute a new satellite debate over “the solution taught by the patent.” I would suggest that the statutorily defined second point, namely “[t]he subject-matter defined by a claim,” is the correct target, and the solution taught by the patent is one relevant consideration..

Finally, I have to note that in addressing the facts, the FCA began by saying that

[76] Had the Federal Court correctly defined the inventive concept, it would have found, at step 3 of the Windsurfer/Pozzoli framework, that there is no difference between the prior art and the inventive concept or the solution taught by the patent. This is to say that there is no difference between (i) atazanavir and its pharmaceutically acceptable salts and (ii) atazanavir bisulfate, a salt of atazanavir which is pharmaceutically acceptable because of its bioavailability.

On one reading, this might be taken as saying that because the species, atazanavir bisulfate, is encompassed within the genus, salts of atazanavir, it is therefore necessarily obvious, even if not specifically disclosed in the prior art. (The prior art 840 patent, which claimed atazanavir and its salts, disclosed only the free base form [266].) That can’t be right, as that would imply that selection patents are not possible, which is contrary to Sanofi: [19]. A new salt species that was not previously disclosed is different from the genus; the right question, as the FCA immediately went on to state, in the same paragraph, is whether the difference between the two can be bridged without inventiveness. On the facts, the answer to that question was yes, and the claimed invention was therefore obvious.

No comments:

Post a Comment