Blinding the Expert Witness in the UK

American Science & Engineering Inc v Rapiscan Systems Ltd [2016] EWHC 756 (Pat)

Earlier this month we saw contrasting decisions on the practice of blinding expert witnesses from Zinn J in Allergan v Apotex 2016 FC 344 (blogged here) and Locke J in Shire v Apotex 2016 FC 382 (blogged here). Just days later, the decision of Arnold J in AS&E v Rapiscan addressed the same question. The invention related to an X-ray security scanning system for use at borders. The main question was the obviousness, and both the patentee, AS&E, and the defendant Rapiscan, introduced expert evidence. They both blinded their experts, but in slightly different ways, neither of which was satisfactory according to Arnold J, who made the following general comments on the expert evidence:

109. Each party contends that the other party instructed its expert to ask himself the wrong question. Both sides’ solicitors proceeded in a carefully structured manner by first asking their expert to consider the person skilled in the art and the common general knowledge, then to consider the prior art relied upon by Rapiscan and only then to consider the Patent. The difference between them was that AS&E’s solicitors asked Dr Bjorkholm to consider obvious developments of the prior art before showing him the Patent, whereas Rapiscan’s solicitors only asked Dr Lanza to consider the question of obviousness after they had shown him the Patent.

110. In my view there is force in the criticisms which each side levels at the other’s approach. The approach adopted by AS&E’s solicitors had the advantage that it enabled Dr Bjorkholm to consider obvious developments of the prior art free from knowledge of the Patent; but it meant that he never addressed in his reports the question of whether the differences between Swift and the claimed invention constituted steps which would have been obvious to the person skilled in the art. The mere fact that a step did not occur to Dr Bjorkholm when reviewing the prior art was not sufficient to exclude the possibility that he might agree that it was obvious if asked. Unlike the person skilled in art, real people sometimes miss the obvious.

111. The approach adopted by Rapiscan’s solicitors avoided that difficulty. The problem is that, whereas the correct question is whether, viewed without any knowledge of the claimed invention, the differences constituted steps which would be obvious, Dr Lanza expressed his understanding of the question he had been asked to consider without referring to the need to exclude knowledge of the claimed invention. Moreover, this does not appear to have been an artefact of the drafting of the report. On the contrary, Dr Lanza confirmed in cross-examination that his approach had been to consider obviousness as if the skilled person had been shown the claims and asked if they were obvious. Thus Dr Lanza does not appear to have understood the importance of trying to avoid hindsight.

AS&E’s expert was untainted by hindsight, but for precisely that reason he was unable to focus on “where the shoe pinches.” Rapiscan’s expert could focus on the crucial question, but his evidence was affected by hindsight. Could the problem have been avoided if Rapiscan had emphasized to their expert the importance of trying to avoid hindsight? I don’t think so. As I recall the research on the hindsight bias, being instructed to avoid hindsight does not significantly mitigate the bias.

The problem is inherent in the Windsurfing/ Pozzoli approach to the obviousness, endorsed by the SCC in Sanofi 2008 SCC 61, [67]. As Lewison J noted in Virgin Airways v Premium Aircrafts Interior 2009 EWHC 26 (Pat) at [271]:

Although the structured approach is relatively easy to describe, it can be very difficult to apply. One reason for this is that at the third stage of the structured approach it is necessary to focus on the differences between the prior art and the patent in suit; but at the immediately succeeding fourth stage it is necessary to erase all knowledge of the alleged invention from the mind. That is not an easy task.

“Not easy” is polite; "impossible" would be more accurate.

The FCA also recognized the problem in E Mishan & Sons, Inc v Supertek Canada Inc 2015 FCA 163 (blogged here):

[36] In applying the fourth step of the Sanofi test, in my view, the requirement that this step be completed “without any knowledge of the alleged invention as claimed” does not mean that the differences that were identified in step 3 would be forgotten for step 4. These differences are an essential part of step 4. Without knowing the differences between the relevant prior art and the inventive concept, step 4 could not be completed. The differences are based on the inventive concept of the claims in issue and the relevant prior art and, therefore, are determined based on some knowledge of what is claimed in the patent in issue. Therefore, some knowledge of the alleged invention will be reflected in the differences that are analyzed in applying step 4 of the Sanofi test.

Thus a expert who is blinded as in AS&E’s approach cannot apply the Windsurfing analysis, but an expert who is not so blinded will have their evidence tainted by hindsight.

Pick your poison.

Markush Claims are Not in the Alternative

Mylan Pharmaceuticals ULC v Eli Lilly Canada Inc (NOC) 2016 FCA 119, Rennie JA, Trudel, Dawson JJA aff’g 2015 FC 17 de Montigny J
            2,226,784 / tadalafil / CIALIS

Claim 18 of the ‘784 patent claims oral administration of tadalafil or 3-methyl tadalafil in treating ED in humans [FC 25]. Mylan challenged the validity of that claim for lack of utility. de Montigny J ultimately held that there was a sound prediction that tadalafil was useful for that purpose [FC 111] (blogged here). Mylan argued that the claim should be held invalid even so, because there was no sound basis for predicting that 3-methyl tadalafil was also useful. de Montigny J held that (1) the claims “are Markush claims and not alternative claims,” and (2) consequently, s 27(5) did not apply and therefore (3) whether the use of 3-methyl tadalafil was soundly predicted is irrelevant as the claim to tadalafil would stand in any event [FC 120]. If this sounds complicated, it is. Each of the steps in this reasoning can be debated – are the claims in question really Markush claims? Does s 27(5) – which provides that “where a claim defines the subject-matter of an invention in the alternative, each alternative is a separate claim for the purposes of sections 2, 28.1 to 28.3 and 78.3” – apply? If it does not, does that mean the “alternatives” (if that is what they are) are independent? (See here a discussion of some of these issues; and be sure to read the very helpful anonymous comment to that post.)

On appeal, the FCA held that “a Markush claim requires that each compound in the claimed class, not merely one of the compounds, have utility” [56] citing von Finckenstein J's decision in Abbott Laboratories v. Canada (Minister of Health) (Clarithromycin), 2005 FC 1095, [23-27], and thus de Montigny J erred in holding that the claim was valid even if 3-methyl tadalafil lacked utility [56]. (The error was of no consequence, as Rennie JA held that the utility of 3-methyl tadalafil was soundly predicted [57].) While Rennie JA did not mention s 27(5), he evidently approved von Finckenstein J's reasoning and not just the result, so this tells us that s 27(5) does not apply to a Markush claim. That is, whether or not de Montigny J was right on point (1), he was right on point (2), but wrong on point (3): all the compounds in Markush claim must have utility (and otherwise claim patentable subject matter) because s 27(5) does not apply.

This is helpful clarification, but it leaves open a few questions. First, the distinction between Markush claims and a claim drafted in the alternative is now very important. How exactly are Markush claims defined? Both von Finckenstein J and de Montigny J emphasized the “and” language in the claim at issue, presumably in contrast to “or” language. Rennie JA said “Assuming, without deciding, that claim 18 was indeed a Markush claim,” de Montigny J erred [56]. One can’t read too much into this language, but it does at least imply that the FCA did not consider it self-evident that Claim 18 was a Markush claim. Claim 18 was a dependent claim and the key Markush language was in Claim 12:

            12.       Use of a compound selected from the group consisting of:

            [tadalafil] or a physiologically acceptable salt or solvate thereof; and

            [3-methyl tadalafil] or a physiologically acceptable salt or solvate thereof,

            for the curative or prophylactic treatment of erectile dysfunction in a male animal.

von Finckenstein J said that a Markush claim “defines a homemade genus, all the members of which can be used interchangeably” [26], but there appears to be some uncertainty as to exactly what language will constitute a Markush claim.

Second, as discussed in my earlier post, Phelan J in Abbott v Apotex / clarithromycin 2005 FC 1332 [50]-[57] held, albeit in obiter, that s 27(5) would not save the claim even if it was framed in the alternative. It seems to me that this must be wrong, for reasons discussed in my earlier post, but I don’t think the FCA decision in this case addresses the point, even by implication.

Publication Date of Second Patent is Not the Date for Assessing Double Patenting

Mylan Pharmaceuticals ULC v Eli Lilly Canada Inc (NOC) 2016 FCA 119, Rennie JA, Trudel, Dawson JJA aff’g 2015 FC 17 de Montigny J
            2,226,784 / tadalafil / CIALIS

The main question addressed in this appeal was the date for assessing obviousness type double-patenting. Double patenting is a judicially created doctrine which prevents an inventor from obtaining a second patent for an invention which is an obvious variant of an invention disclosed in its own prior unpublished prior application, even though that prior application is not part of the state of the art defined in s 28.3. So, in Com'r of Patents v. Farbwerke Hoechst [1964] SCR 49, the SCC held that Hoechst’s application for a patent for a medicine consisting of sulphonyl urea diluted by a carrier should be rejected as not inventively distinct over Hoechst’s prior application for a patent for sulphonyl urea, given that there was no inventive step in mixing sulphonyl urea with a carrier.

If the state of the art does not change, then the date at which double patenting is assessed does not matter; in Hoechst it had always been common general knowledge that a medicine could be mixed with a carrier. But when the common general knowledge changes, the date is important. That is what happened in this case.

The question was whether Lilly’s ‘784 patent was invalid for obviousness-type double patenting over Lilly’s 2,181,377 patent. The ‘377 patent claimed tadalafil, which is a PDE V inhibitor. It had a priority date of 21 Jan 1994. The ‘784 patent claimed tadalafil for the treatment of erectile dysfunction (ED). It had a priority date of 14 July 1995. The publication date of the ‘784 patent was 6 Feb 1997. Between the first date and the last there were two new pieces of information available to the public. On 22 Dec 1994, Pfizer’s ‘902 US patent application was published, disclosing that sildenafil, another PDE V inhibitor, was useful for treating ED [6]. In June 1996 the Boolell study was published, which provided good evidence that a PDE V inhibitor could be administered orally for safe, effective treatment of ED [7]. The timeline was conveniently summarized by Rennie JA in this chart:


If the relevant date for assessing double patenting was the publication date of the‘784 patent, then it was uncontroversial that it would be obvious, because the ‘377 patent disclosed that tadalafil is a PDE V inhibitor and the Boolell paper disclosed that any PDE V inhibitor would be effective to treat ED [46].

The FCA rejected that date. Mylan had argued that Whirlpool 2000 SCC 67 mandated the use of the publication date of the later patent [15], presumably on the basis that Whirlpool [55] had held that the claims had to be construed as of the date of publication [55, 56]. Rennie JA held that Whirlpool was not controlling authority on this point, essentially on the basis that the question of the correct date was not at issue [48]. The refusal to decide the issue by exegesis of Whirlpool strikes me as sound both in law and as a matter of policy. In R v Henry, 2005 SCC 76 [57] the SCC pointed out that its dicta is to be treated as binding only when obviously “intended for guidance,” and “[t]he notion that each phrase in a judgment of this Court should be treated as if enacted in a statute is not supported by the cases and is inconsistent with the basic fundamental principle that the common law develops by experience.” It is better to rely on the considered reasoning of the FCA on the merits of the issue, rather than an attempt to discern what the SCC might have intended on an issue which it never addressed.

Turning to the merits, Rennie JA held that it would be inappropriate to use any date later than the claim date of the second patent because that would permit consideration of information arising after the patent’s claim date, contrary to s 28.3 [50]. For example, pretend the the ‘377 patent didn’t exist and suppose the Boolell paper was published in August of 1996, so that no one knew that PDE V inhibitors could be used to treat ED until then. If double patenting was assessed as of February 1997, the ‘784 patent would be held invalid for obviousness, even though on the claim date of the ‘784 patent it was not obvious to anyone that tadalafil could be used to treat ED – not even to someone with full knowledge that tadalafil was a PDE V inhibitor, as disclosed by the ‘377 patent. That cannot be right, as Lilly would have made two distinct contributions to knowledge, namely that tadalafil was a PDE V inhibitor, and that tadalafil could be used to treat ED.

The next question is whether the claim date of the ‘377 patent should be used, or the claim date of the ‘784 patent. Rennie JA held it was not necessary to decide [52], because de Montigny J had held [147] that notwithstanding the disclosure of Pfizer’s ‘377 patent, on the claim date of the ‘784 patent it was still not thought that oral administration of a PDE V inhibitor would be effective in treating ED. That is, the ‘377 patent did not change the common general knowledge and therefore the use of tadalafil to treat ED would not have been obvious over the ‘377 patent and the common general knowledge even at the priority date of the ‘784 patent. This was a finding of fact which was entitled to deference [53]. It might be said that the FCA should have decided the point anyway to provide clarity, particularly since it was fully argued, but on the whole I think the point is difficult enough that the FCA was right to leave it to a case in which it is determinative. I haven’t had any fresh thoughts of my own on which of those dates is preferable since I wrote my post on the decision of de Montigny J (here) and the more fully considered comments on Gleason J’s decision (here).

Exception to Implied Undertaking Rule

Gilead Sciences, Inc v Teva Canada Ltd 2016 FC 31 Tabib J aff’d 2016 FC 336 Barnes J
     2,261,619 / 2,298,059 / tenofovir disoproxil / TRUVADA ATRIPLA VIREAD

My post on Barnes J’s decision affirming Tabib J’s refusal to strike Gilead’s quia timet action focused on what is meant by “imminent” activity, but Tabib J’s decision is also interesting because she relieved Gilead of the implied undertaking rule, pursuant to which a party is prevented from using information obtained on discovery for any other litigation or purpose [1].

In 2011 and 2012 NOC proceedings commenced between Gilead and Teva in respect of products covered by the 059 and 619 patents [5]. In August 2012, while those proceedings were pending, Teva brought an action seeking a declaration that the 619 and 059 patents were invalid [6]. In December of 2013 the FC granted an order prohibiting Teva from launching prior to expiry of the 619 patent, but dismissing the application in respect of the 059 patent. Teva initially continued to prosecute its impeachment action in respect of both patents, but a year later, in December of 2014, it discontinued the action in relation to the 059 patent, though without amending the pleadings [8]. Gilead then instituted the present quia timet action, seeking a declaration that Teva had in the past and will in the future infringe the 059 Patent [10].

The 059 and 619 patents related to the fumarate salt of tenofovir disoproxil (TDF). In its impeachment action Teva alleged that it wishes to import, make, use and sell in Canada TDF or products containing TDF [13]. In bringing its quia timet action, Gilead sought to rely on this statement as a material fact supporting its allegation to the effect that Teva intends to and will import, make, use and sell in Canada products containing TDF prior to the expiry of the 059 patent [12]. In order to do this, Gilead sought to be relieved of the implied undertaking rule [1].

Tabib J noted that, inter alia, “the rule encourages parties to provide a more complete and candid discovery, again, furthering the interest of justice by giving them some assurance that the documents and answers will not be used for a purpose collateral or ulterior to the proceedings,” but the rule “is not however absolute and the Court retains the power to relieve persons of the obligation where it is in the interest of justice to do so” [14]. Tabib J noted that there is a recognized exception when “the deponent has given contradictory testimony about the same matters in successive or different proceedings,” and essentially the same consideration was at interest in this case [16]:

[17] Where it suited its purpose, as plaintiff in the . . impeachment action, Teva publicly described itself as an interested party on the basis of express allegations of an intent to come to market with products containing TDF prior to the expiry of the subject patents. It is fair to say that any facts that may have been disclosed on discovery by Teva to flesh out or support these allegations were proffered to advance Teva’s own interests in that litigation. . . . In the circumstances, the implied undertaking would permit Teva to play games with the administration of justice and to tailor its litigation position to suit its needs in each particular proceeding.

Tabib J also noted that “the narrow issue of whether Teva intends to and will come to market prior to the expiration of the 619 and/or 059 Patents is not just similar, it is the same. Teva cannot claim that they are distinct merely because the current action concerns only the 059 Patent while the [impeachment] action no longer concern that Patent: At the time discovery was given, the 059 Patent was directly at issue” [20]. Consequently, she held that Gilead is relieved of the implied undertaking rule in respect of the excerpts of discovery transcripts identified in its motion record.

More Disagreement with Rennie J on Application of Enhanced Disclosure Requirement for Sound Prediction

Allergan Inc v Apotex Inc 2016 FC 344 Zinn J
            2,307,632 / gatifloxacin ophthalmic

Zinn J packed a number of legal issues into this short decision. As well as the issue of blinding the expert witness, discussed in yesterday’s post, his analysis of utility is also interesting.

First, like Barnes J in Lilly v Hospira 2016 FC 47 (blogged here), Zinn J disagreed with the view expressed by Rennie J in Apotex / esomeprazole 2014 FC 638 [141] that the requirement to disclose the factual basis and the line of reasoning for a sound prediction of utility is “limited to the context of ‘new use’ patents, assuming such a utility disclosure requirement exists at all” (see here). Zinn J’s reasoning echoed that of Barnes J:

[57] With the greatest of respect to the views of Justice Rennie, I am not prepared to depart from established jurisprudence directly on point from the higher courts by relying on obiter statements of a few judges in cases where the issue of utility was not fully and thoughtfully addressed. In my view, until the Federal Court of Appeal or the Supreme Court of Canada rules otherwise, Canadian jurisprudence is that, with the exception of matters of common general knowledge, the factual basis and the line of reasoning must be included in the patent.

Thus it is increasingly clear that Rennie J’s view will not carry the day at the FC level without further guidance from a higher court.*

Second, Zinn J applied the promise doctrine to hold that to hold that utility should be assessed against three promises set out in the disclosure, and not against the lower scintilla standard [48]. He rejected the argument that expressed advantages were merely goals, on the basis that the promised utility was “clearly and unequivocally described” in the patent [46]. This reaffirms that any positive statement of utility will normally be taken as a promise. Zinn J’s holding is not particularly remarkable taken in isolation, but taken cumulatively with other cases on the promise of the patent, it is now evident that the FCA’s Plavix 2013 FCA 186 decision, which seemed to signal a more restrained approach to applying the promise doctrine, has turned out to have had very little impact on the law.

On the facts of the case, Zinn J held that not all of the three promises of the ‘632 patent had been met. The ‘632 patent claimed a pharmaceutical composition of gatifloxacin and disodium edetate (EDTA). Only Claim 10, which claimed EDTA in an amount of 0.01 to 0.1 w/v%, was in issue. One of the three promises was that the addition of EDTA would prevent precipitation of gatifloxacin crystals [46]. Utility was not demonstrated, because limited testing had been done [50], and while Zinn J accepted that EDTA in the tested formulations disclosed in the patent – 0.05% and 0.1% w/v% – did in fact impact the precipitation of gatifloxacin, he found that there was no evidence that this would allow a prediction that the same result would be obtained with the lower levels of ETDA (down to 0.01%) specified in Claim 10 [60]. It’s not clear to me how to reconcile this finding with Zinn J’s finding in the context of obviousness that “a POSITA would have a fair and reasonable expectation that combining gatifloxacin with EDTA would produce an effective ophthalmic compound that would have the three advantages set out in the 632 Patent“ [39], given that the three advantages considered in the context of obviousness corresponded to the three promises of utility, including prevention of precipitation [27]. Perhaps it would have been obvious to a POSITA that levels of EDTA greater than 0.05% would have reduced precipitation, but it would not have been predictable that lower levels would have the same effect. 

*UPDATE:  I've just recalled that in Gilead v Idenix 2015 FC 1156 [380] Annis J agreed with Rennie J on this point. That means the cases are divided 2-2 at the FC level, so it is perhaps not so clear how this will play out in the Federal Court. In any event, the matter will have to be resolved by the FCA in due course.

Expert Witness Preferred Because of Blinding

Allergan Inc v Apotex Inc 2016 FC 344 Zinn J
            2,307,632 / gatifloxacin ophthalmic

Yesterday morning I posted on Shire v Apotex 2016 FC 382, in which Locke J gave little weight to the practice of “blinding” the expert witness; then in the afternoon the FC released Allergan v Apotex, in which Zinn J has taken almost the opposite approach to the same issue. Apotex prevailed on the issue of obviousness primarily because Zinn J preferred the evidence of one of Apotex’s witnesses [8], and he preferred the evidence of that witness primarily because she was blinded (though also in part because her expertise was more directly relevant to the issue at hand) (my emphasis):

[12] While I am not convinced that all of these alleged flaws are made out, I am satisfied, for the following reasons, that the evidence of Dr. Sheardown [Apotex’s expert] is to be preferred and given more weight than that of Dr. Fix [Allergan’s expert] and Dr. Myrdal [Apotex’s expert].

[13] As noted by Apotex, Dr. Fix was not blinded; he offered his opinion after having read the 632 Patent and Apotex’s NOA and after having discussed both with Allergan. The Supreme Court of Canada in Apotex Inc v Sanofi-Synthelabo Canada Inc, 2008 SCC 61,[2008] 3 SCR 265 [Plavix SCC] at para 67, directs that an obviousness assessment is to be made “without any knowledge of the alleged invention as claimed.” Relying on this observation, this Court has recognized that evidence from experts who have not seen the patent nor been apprised of the positions of the litigants is to be given greater weight on issues going to obviousness and patent construction than the evidence of an expert with full knowledge of the patent’s disclosure and the positions of the parties: [citations omitted]

[14] Like Dr. Fix, Dr. Myrdal had prior knowledge of the 632 Patent (or the U.S. equivalent) and the positions of the parties. As acknowledged by Apotex, “[Dr. Myrdal] testified in a United States case on the corresponding patent and his evidence … in the present proceeding was consistent with his U.S. evidence.”

[16] Unlike the other experts in pharmaceutical formulation, Dr. Sheardown expressed her opinion on the common general knowledge and the prior art with no knowledge of the patent at issue or the positions of the parties. As such, her responses to the questions asked of her came without any influence, conscious or unconscious. Moreover, of the three, only Dr. Sheardown’s expertise focused on “studying and developing delivery formulations for ophthalmic applications.” Dr. Fix and Dr. Myrdal are expert formulators. However, given that the alleged invention in the claims at issue is specifically directed to an ophthalmic medication in the form of an eye drop, I am of the view that the evidence of the one expert specializing in that area, whose opinion is offered with no possible influence, is to be preferred.

As discussed here, the FCA in Mishan v Supertek 2015 FCA 163 recognized an inherent tension in the SCC’s approach to obviousness. On the one hand, Sanofi [67] says that the differences between the state of the art and the inventive concept must be “[v]iewed without any knowledge of the alleged invention as claimed.” But that is impossible: “The differences are based on the inventive concept of the claims in issue and the relevant prior art and, therefore, are determined based on some knowledge of what is claimed in the patent in issue. Therefore, some knowledge of the alleged invention will be reflected in the differences that are analyzed in applying step 4 of the Sanofi test” [Mishan v Supertek [36]].

So far as I can tell, in this case that tension was resolved by having Dr Sheardown express her opinion “on the common general knowledge and the prior art” [16] without knowledge of the patent or the position of the parties, but she must have then been provided with the patent before opining that “There is no practical difference between the inventive concept of the claims of the 632 Patent and the common general knowledge. Any differences between the inventive concept and the claims of the 632 Patent and what was known to the skilled person as of August 1998 constituted steps that would have been obvious to the skilled person” [34].

There are also two sides to this debate as a matter of policy. While blinding an expert may help avoid hindsight bias, unless the expert is asked to focus on “where the shoe pinches” it might be difficult to elicit relevant evidence. Also, as noted in yesterday’s post, the issue has arisen in the context of claim construction as well as obviousness. Is there a principled difference between the two contexts which would rationalize the divergent case law? In any event, the law on this point continues to develop, but until some consensus is reached it will be difficult to know how to instruct an expert.

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.

How Accurate are Damages Calculations?

TearLab Corp v I-Med Pharma Inc 2016 FC 350 Russell J

2,494,540 / TearLab System / i-Pen System

This cases raises, albeit indirectly, the interesting question of how it could be shown that damages are inadequate for the purpose of establishing irreparable harm.

Russell J refused to grant an interim injunction in favour of TearLab which would have prevented I-Med from launching its allegedly infringing product pending a motion for an interlocutory injunction. (TearLab is the exclusive licensee of the University of California's ‘059 patent [6].) Russell J’s reasons followed established Canadian law. To get an interim or interlocutory injunction, the patentee must show irreparable harm, and the standard for showing such harm is stringent: the evidence of harm must be “clear and not speculative”, the harm itself must flow almost inevitably, and mere difficulty of calculating damages does not constitute irreparable harm, “provided there is some reasonably accurate way of measuring those damages” [43]. In this case, Russell J held that the evidence presented by TearLab did not satisfy these requirements.

Russell J’s conclusion was not very surprising on the facts. TearLab relied on the evidence of Mr Tierney, the retired business director of Allergen Eye Care, to the effect that there was no good model for quantifying TearLab’s losses [38]. But as Russell J pointed out, Mr. Tierney was not an expect in market forecasting or quantification of damages. And in any event, the courts have long acknowledged that damages assessment is a “broad axe” not a “rapier point,” and mere difficulty of calculating damages does not establish irreparable harm. There is an argument to be made that “meaningful doubt as to the adequacy of damages” should be sufficient to constitute irreparable harm, at least as a part of a balancing analysis, but that view has not carried the day in the Federal Courts.

This raises the question of whether it is possible, even in principle, for a patentee to establish to the satisfaction of the Federal Court that the difficulty in assessing damages is sufficient to constitute irreparable harm. The legal question is whether “there is some reasonably accurate way of measuring those damages.” On its face this seems to be an objective question capable of being addressed with the right kind of evidence. But question may be circular. The difficulty is that, so far as I know, the damages assessment itself is the best method we have of establishing the true loss. In s 8 and pharma damages cases, for example, sophisticated economic models are used to assess the difference between pharmaceutical prices with and without generic entry. In the absence of some more accurate method of assessment then it will be impossible to prove that damages are not reasonably accurate. But in light of the widespread judicial acknowledgement of uncertainties in damages calculations, even the best possible estimate of damages is not necessarily reasonably accurate. There is a difference between saying that damages are $1,000,000 plus or minus $1,000, and saying damages are $1,000,000 plus or minus $1,000,000. 

How accurate are damages assessments? In principle a formal error analysis of existing methods of damages assessment could address this question. However, that would be demanding from an evidentiary perspective, as the patentee and alleged infringer would be not only arguing over the quantum, but also over the accuracy of the quantum, which adds a layer of complexity to an already complex inquiry. And from a strategic perspective, the patentee would be caught in a squeeze, as it would want to argue that the errors are large in order to establish that damages assessments are not accurate in order to obtain an interlocutory injunction, but that would mean conceding the possibility that its subsequent damages claim might fall in the lower end of the range. My point isn’t that it is unfair to put the patentee in this squeeze, but rather that there are practical reasons why evidence of the accuracy of damages assessment is unlikely to be forthcoming. Another practical problem is that undertaking an error analysis in order to make the case for an interlocutory injunction would be very expensive and likely to be worth the cost only in pharma cases (if even there). Given that pharma has the NOC system which provides a statutory interlocutory injunction, it is hard to imagine a case in which it would be worthwhile for a plaintiff to incur this expense. Perhaps this is an issue that could be addressed by an academic economist.

“Imminence” in a Quia Timet Action

Gilead Sciences, Inc v Teva Canada Ltd 2016 FC 336 Barnes J aff'g 2016 FC 31 Tabib J
     2,261,619 / 2,298,059 / tenofovir disoproxil / TRUVADA ATRIPLA VIREAD

In this decision Barnes J upheld Prothonotary Tabib’s refusal to strike Gilead’s quia timet action. The most interesting aspect of the decision concerns what is meant by “imminent” activity.

In the prior NOC proceeding 2013 FC 1270 (blogged here), Gilead had sought an order of prohibition based on the ‘619 and ‘059 patents. Barnes J held that the ‘059 patent, for the fumarate salt form of tenofovir disoproxil, was invalid as obvious, but he held the ‘619 patent, to tenofovir disoproxil itself, was valid and he granted an order prohibiting in the Minister from issuing an NOC to Teva in respect of its tenofovir disoproxil fumarate product until the expiry of the ‘619 patent. Gilead is now seeking to bring a quia timet infringement action, presumably based on the ‘059 patent (though that is not stated expressly in the decision).

Teva sought to strike Gilead’s Statement of Claim on the basis that it did not satisfy the test for maintaining a quia timet proceeding which was set out in Connaught Labs, [1998] FCJ No 1851, 86 CPR(3d) 36, [18] (my numbering):

[1] the statement of claim must allege a deliberate expressed intention to engage in activity the result of which would raise a strong possibility of infringement;

[2] the activity to be engaged in must be alleged to be imminent and the resulting damage to the plaintiff must be alleged to be very substantial if not irreparable; and,

[3] finally, the facts pleaded must be cogent, precise and material.

Barnes J held that the first part of the test was satisfied, as Teva had declared an intention to come to market with a competing version of Gilead’s tenofovir disoproxil product as soon as it could obtain an NOC, and while this was not completely inevitable, the “strong possibility” found by Tabib J was consistent with Connaught and other cases [9].

Teva also argued that the allegedly infringing activity was not “imminent” because the probable date of launch was 22 months away, on expiry of the ‘619 patent. Barnes J at [10] rejected this argument, approving Tabib J's statement that:

The purpose of a quia timet action is to stop an event before it happens. Given that streamlined infringement actions may now be heard and determined in two years, it is neither premature nor pointless to institute such an action 22 months before the occurrence of the event to be avoided.

Moreover, Barnes J helpfully clarified why there is a requirement of imminence at all. The purpose of the restrictions on the quia timet proceeding is to avoid wasting judicial resources on an action that may turn out to be pointless. On that rationale, if the allegedly infringing action is inevitable, it shouldn’t matter whether it will happen tomorrow or ten years from now. But, as Barnes J explained:

[11] [T]he requirement of imminence in the temporal sense may be relevant in the determination of the likelihood of a future event. A potential event that is more distant in time may be an event that is less likely to occur.

Imminence is not directly relevant, but only in so far as it affects the probability of the future event. This implies that “imminence” is not to be judged solely temporally, but in a balance with other evidence of the likelihood of the future event. By the same token, “temporal imminence appears to be a subordinate consideration in a case where the likelihood of future harm appears high” [11].