Moderation in Blinding Expert Witnesses

Shire Canada Inc v Apotex Inc (NOC) 2016 FC 382 Locke J
            2,348,090 / mixed amphetamine salts (MAS) / ADDERALL XR

In this decision Locke J dismissed Shire’s motion for an order of prohibition in respect of Apotex’s extended release mixed amphetamine salts (MAS) on the basis of non-infringement, without addressing the other grounds raised. The decision turned on claim construction, and while Locke J considered a variety of technical arguments, in the end his construction and the consequent conclusion of non-infringement was quite straightforward. The most interesting aspects of the decision are Locke J's comments on “blinding” of expert witnesses, and his analysis of the inconsistency in the SCC’s Free World Trust decision on claim construction.

The ‘090 patent is entitled “Oral Pulsed Dose Drug Delivery System.” It claims an extended release formulation of mixed amphetamine salts which mimics a twice-daily dosage by means of “an immediate release dosage form containing a first dosage amount . . . and a second dosage form containing a second dosage amount . . .which has a release onset lag time,” with a correspondingly pulsed release profile [80]. Examples in the patent describe a capsule containing one dose in an immediate release form combined with a second dose in an enteric coating. Apotex’s product, in contrast, is a uniform tablet consisting of a uniform matrix in which MAS and excipients are dispersed in an enteric polymer [23]. It achieves its extended-release characteristics by virtue of the changing release mechanism from diffusion to a combination of diffusion and erosion as the tablet passes from the stomach into the intestine [24]. The technical claim construction exercise confirmed that this took Apotex’s product outside the claims of the ‘090 patent [157]. Locke J’s claim construction analysis strikes me as entirely compelling.

Of more general interest are Locke J's comments on “blinding” the expert witness, a practice which has been raised in a couple of recent cases. To recap, in Esomeprazole 2014 FC 638 Rennie J made the following remarks, in the context of obviousness (my emphasis):

[321] First, Apotex’s experts’ disbelief in a fear of racemisation facing the skilled chemist is more credible because its experts more closely emulated the perspective of the skilled person. Drs. Jacobsen and Danheiser (for Apotex) had mandates that allowed them to opine on the state of the art, in the words of the Supreme Court of Canada, “viewed without any knowledge of the alleged invention as claimed” (Sanofi-Synthelabo Plavix, at para 67), while both Drs. Davies and Armstrong (for AstraZeneca) did not. More specifically, the Apotex experts were “blinded” from the 653 for their initial reports addressing whether and how the enantiomers of omeprazole could be obtained. By contrast, Dr. Davies has given extensive evidence in prior esomeprazole litigation, while Dr. Armstrong, to a lesser extent, has also addressed the ‘653 patent in a prior case

Then, in her Rasagiline 2014 FC 1070 decision, (blogged here, and see also here) Gleason J, citing Rennie J’s Esomeprazole 2014 FC 638 decision, made this statement in the context of claim construction (my emphasis):

[94] Secondly, I agree that the manner in which the experts were retained and instructed in this case provides a reason to prefer the evidence of the Apotex experts over that of the Teva experts. Because they did not know what alcohol Apotex had used in its Products when they conducted their construction exercise, their interpretation was undertaken in accordance with the direction from the Supreme Court of Canada, requiring that the construction exercise be uninfluenced by concerns over infringement or invalidity. The Teva experts, on the other hand, conducted their construction of the terms with a view to the potentially infringing substance. This is evident from the terms of their affidavits, which indicate that the molecular structure of [. . .] was factored into the construction exercise.

These cases indicated a nascent trend in favour of “blinding” experts. But then in Apotex / Tadalafil 2015 FC 875, Gleason J resiled somewhat from this suggestion (my emphasis):

[166] Insofar as concerns the allegation regarding lack of “blinding”, Apotex has tried to apply the decisions in Teva [Rasagiline] and AstraZeneca [Esomeprazole] out of context. There, the experts whose credibility was found to be wanting based their construction of the patents in suit with a view to infringement and were able to come to their opinions based on the information in the generic company’s NOA. In Teva, this led to an especially tortured construction. In Teva and AstraZeneca, the approach taken was found to undercut the experts’ credibility as it led to an improper results-oriented opinion. Neither case can be read for the position that Apotex sought to advance here, namely, that in any case where one party blinds its experts but the other does not, the former’s evidence is to be preferred. Rather, these two decisions must be limited to the facts that arose in these cases.

In the case at hand Apotex’s experts never saw the NOA and were never told Apotex’s legal position, while Shire’s experts were not similarly blinded [42]. Apotex argued that the evidence of its experts should be preferred for that reason [43]. Locke J rejected this suggestion, at least insofar as it would represent a general rule (citations omitted):

[45] I agree to some extent with both parties. In some situations, the fact that an expert witness was unaware of the features of an allegedly-infringing product when they formed their opinion on claim construction may be helpful in deciding the weight to be placed on that expert’s opinion. However, I agree with Shire that favouring the evidence of experts who have been blinded has not been raised to the level of a legal principle that must be applied in all cases, and is merely persuasive. I am mainly interested in the substance of an expert’s opinion and the reasoning that led to that opinion. If it is well-reasoned, there may be no reason for concern about whether the witness was blinded to certain facts when giving the opinion. A concern may arise where the expert’s opinion seems tortured or less well-reasoned.

The reference to “tortured” evidence echos Gleason J’s statement in Tadalafil. This suggests that blinding an expert will only be helpful if the expert's evidence seems tortured. While that would normally be a reason for discounting the evidence, if the tortured evidence was obtained from an expert who had been blinded, it might nonetheless retain some credibility.

Locke J also made a very interesting critique of the premise of the argument in favour of blinding:

[46] I am also conscious that the blinding of witnesses is no guarantee that the expert evidence before the Court is reliable. It would not be difficult (though it would be expensive) for an unscrupulous party to seek opinions from a number of experts, keeping them all blind to unnecessary information. If one of those many experts provided the opinion that the party sought and all of the others concluded otherwise, the party would be able to retain the outlier and present him or her as a blinded (and therefore reliable) witness.

Finally, on a different topic entirely, Locke J also had an interesting “Aside on claim construction principles” [134]–[144], in which he discussed the evident inconsistency between the SCC’s Free World Trust 2000 SCC 66 claim construction principles and its treatment of the so-called Improver questions (originally formulated by Lord Hoffmann when he was sitting in Chancery). After reviewing a number of cases and commentators discussing the problem, Locke J concluded (original emphasis) that:

[137] In my view, the SCC likely intended that, in order for a patentee to establish that a claim element is non-essential, it must show both (i) that on a purposive construction of the words of the claim it was clearly not intended to be essential, and (ii) that at the date of publication of the patent, the skilled addressees would have appreciated that a particular element could be substituted without affecting the working of the invention.

I won’t go into the details, as the discussion is arcane, even by patent law standards. Lord Hoffmann himself has called the Improver questions a mangle (Kirin-Amgen [2004] UKHL 46, [52]), and it is fair to say that the SCC’s gloss did not clarify them. Moreover, the Improver questions are rarely used, and nothing in Locke J’s interpretation of Free World impacted his decision – as he said, it was an aside. But if the question does arise again, Locke J’s analysis will have to be taken into account.