"Some leeway" Standard of Review for Claim Construction

NOVA Chemicals Corporation v The Dow Chemical Company, 2016 FCA 216 de Montigny JA: Webb, Boivin JJA aff’g 2014 FC 844 O'Keefe J here
            2,160,705 / film-grade polymers / ELITE SURPASS / Action

At trial in this action O’Keefe J held Dow’s ‘705 patent related to film-grade polymers to be valid and infringed by NOVA. In my post on that decision I noted that “[t]he result turned largely on the evidence, and no novel points of law were raised.” Unsurprisingly, the FCA has now affirmed, noting that “[a]ll of the arguments raised by the appellant amount to no more than mere disagreements with the Judge’s factual findings and assessment of the expert evidence” [93]. With that said, there are a few points of general interest in the decision relating to the nature of claim construction, the meaning of “comprising,” and the promise of the patent.

The most significant point is the Court’s remarks on the nature of claim construction:

[15] On the other hand, the construction of the patent is to be reviewed on the basis of correctness. As the Supreme Court has stated in Whirlpool Corp. v. Camco Inc., 2000 SCC 67 at para. 61, [2000] 2 S.C.R. 1067, “claims construction is a matter of law”. That being said, I share the concerns of my colleague Justice Stratas that it will often be difficult, if not unrealistic and artificial, to distinguish between those aspects of claim construction that flow from the trial judge’s assessment of expert evidence from the words of the claim themselves (see Cobalt Pharmaceuticals Company v. Bayer Inc., 2015 FCA 116 at paras. 16-24, [2015] F.C.J. No. 555). After all, the construction of a patent is heavily dependent on the evidence given by persons skilled in the art, and that evidence will bear heavily on the judge’s findings. For that reason, I accept (as I must) that the construction of a patent is a question of law to be reviewed on a standard of correctness, but trial judges are nevertheless entitled to some leeway as they are often in a much better position than appellate judges to understand the intricacies of the art underlying the invention disclosed in a patent.

“Some leeway” is an interesting caveat to the correctness standard, which arguably amounts to a halfway (quarterway?) house between correctness and deference. Substantively, it is seems like a reasonable position in light of the concerns identified by the FCA. In principle the expert evidence enables the court to understand the meaning of the technical terms – a factual inquiry – while the court interprets the claims in light of that understanding – a legal inquiry. But since words take their meaning partly from the context in which they are used, it is not possible to separate the two inquiries so neatly. However, as the FCA notes, claim construction is a matter of law, and the standard is therefore correctness, and it is not clear that giving the trial court “some leeway” is consistent with the correctness standard. Moreover, whether as a third level of deference, or simply a caveat to correctness which is applicable to claims construction, it runs counter to the general trend of simplifying the standards of review, as illustrated by Dunsmuir [2008] 1 SCR 190, Housen v Nikolaisen 2002 SCC 33, and most recently in the FCA’s own decision in Hospira 2016 FCA 215 (discussed here). I note that the FCA did not embrace the correctness standard on its merits, but rather because of binding SCC authority. Do I detect some dissatisfaction with the SCC’s holding in this paragraph? Perhaps the FCA is hinting that it would prefer a fully deferential standard of review for claim construction and “some leeway” is the furthest it felt it could go in light of Camco. But a fully deferential standard would have its own significant problems, and maybe it is better to accept the decision on its face, as fully endorsing a standard of correctness with some leeway, even if that leaves a tension with broader trends.

On another claim construction point, the FCA affirmed O'Keefe J’s construction of the word “comprising” as meaning “including, but not limited to” [81]. The FCA stated that Nova’s argument to the contrary “is inconsistent with the ordinary meaning of the word ‘comprising’” [82] The Court also noted that “the traditional meaning of the word ‘comprising’ is ‘including but not limited thereto’” [82]. This is a welcome departure from the FCA’s decision in Purdue Pharma / TARGIN 2011 FCA 132, where, as discussed here, the FCA held in effect that “comprising” has no presumptive meaning. The FCA in this case did acknowledge that “a presumption should not be applied inflexibly” [83], so it is possible that “comprising” might be interpreted as limiting in the context of a different patent. However, even that statement helpfully recognizes that there is indeed a “presumption” that “comprising” is not normally limiting.

Finally, the utility argument at trial had turned on the construction of the promise of the patent, and O’Keefe J had held that there was no promise at all, so that utility should be assessed against a scintilla standard. The FCA affirmed, referring to the “presumption that an inventor should only be held to an elevated standard where a clear and unambiguous promise has been made,” and citing Celecoxib 2014 FCA 250 [66] (blogged here), for the proposition that “[w]here the validity of a patent is challenged on the basis of an alleged unfulfilled promise, the patent will be construed in favour of the patentee where it can reasonably be read by the skilled person as excluding this promise” [24]. It might be possible to read this as generally emphasizing the need for restraint in construing the promise of the patent, reinforcing Plavix 2013 FCA 186 (here). However, as the FCA also emphasized, in this case the argument for an enhanced promise was weak in any event. We’ll learn more when the FCA next reviews a construction of the promise that is closer to the line, one way or the other.

UPDATE: In preparing this post, I neglected to review Cobalt v Bayer 2015 FCA 116, which was cited by the FCA in the key paragraph 15, quoted above. As discussed in my post on that decision, Stratas JA explicitly argued for a deferential standard of review in construction of the patent at [12]-25]. So the answer to the question I posted above, as to whether the FCA in this case is expressing some dissatisfaction with the correctness standard and hinting that it would prefer a more deferential standard, is evidently "yes." In my post on Cobalt v Bayer I argued that while there are compelling arguments against reviewing claim construction on a correctness standard, there are also problems with a fully deferential standard. I'm now inclined to think that the modestly deferential "some leeway" standard might be the best approach, notwithstanding the trend towards simplification of standards of review.