Tuesday, March 23, 2021

A Selection Patent Does Not Differ in Substance or Form from Other Patents

Apotex Inc v Shire LLC 2021 FCA 52 Rennie JA: de Montigny, Gleason JJA affg 2018 FC 637 Fothergill J

            2,527,646 / lisdexamfetamine [LDX] / VYVANSE / NOC

Rennie JA’s decision for the FCA is noteworthy in three respects. First, Rennie JA held in the clearest of terms that nothing turns on whether a patent is characterized as a selection patent. This is a welcome reaffirmation of prior holdings to much the same effect, but this decision is important because the issue was central to the appeal and the FCA’s holding was so unequivocal. The issue can now be considered settled, as I’ll discuss in this post. Second, Rennie JA provided an extensive discussion of the role of the inventive concept in the obviousness analysis. In many ways this discussion is a helpful clarification of the law, but I must admit that there are some aspects of the decision that make me nervous. I’ll have another post on that issue.

Third, Rennie JA reaffirmed that the various “obvious to try” considerations factors set out in Sanofi 2008 SCC 61 [69]–[70] are factors, not requirements, and they need not all be met [106]–[107[. Normally I would devote a post to this aspect of the decision, but I discussed the issue at length in my very recent post on the decision of Locke JA (Webb, Boivin JJA concurring) in Zytiga 2021 FCA 45, which addressed the point at greater length. The decision of Rennie JA in this case appears to me to be entirely consistent with that in Zytiga, so I won’t blog separately on this aspect of the decision. The important point is that we now have two separate panels of the FCA expressing the same view. In Zytiga Locke JA stated that “I maintain my view that ‘more or less self-evident that it ought to work’ should be treated as a factor in the obviousness to try analysis, and not as a requirement” [36]. This way of putting it suggested that there might be some question as to how widely that view is shared. In light of Rennie JA’s decision in this case, I think this point too can now be considered settled.

As discussed in my post on Fothergill J’s decision, the 646 patent relates to the compound LDX and its use for treating ADHD. Amphetamines have long been used to treat ADHD, but they can be abused by snorting or injection. LDX provides a solution to that problem in the form of an abuse-resistant sustained release prodrug [31]. The main validity attack was based on AU Patent No 54168/65, which disclosed a very large class of related compounds. None of the specific examples disclosed LDX itself, but LDX was included in as one of the many possible configurations in the “advantageous” class described on page 4 of AU 168 [FC 104]. The advantages of LDX as a solution to the problem of amphetamine abuse were not described in AU 168 [FC 108], and the compounds were not even identified as prodrugs [FC 107]. The thrust of AU 168 was that the disclosed compounds might be useful as appetite suppressants that are substantially free of CNS stimulatory activity [FC 106].

There was a question as to whether the 646 patent was a selection patent over AU 168. Fothergill found it unnecessary to decide this question [29], [FC 98], essentially on the view that nothing turned on that point:

[FC 97] By statute, the basis for assessing anticipation cannot depend on whether the patent is a selection patent or not. The jurisprudence does not imply that anticipation and obviousness in respect of a selection patent are to be assessed over the genus patent from which it is a selection, rather than over the prior art read as a whole. A selection patent “does not in its nature differ from any other patent” (Sanofi-Synthelabo at para 9), there is no reference to selection patents in the Patent Act, and the conditions for a valid selection patent do not constitute an independent basis upon which to attack the validity of a patent. A selection patent, like any other patent, is therefore vulnerable to any attack set out in the Patent Act, but no other.

Apotex argued that this was an error, and that it does matter whether the 646 patent is a selection patent. In particular, Apotex argued that the advantageous properties of a compound over the prior art may only be considered if the patent is a selection patent over that prior art; otherwise, only the bare chemical formula should be considered [19].

Rennie JA firmly rejected this argument. While he did not specifically refer to Fothergill J’s remarks at [FC 97], his holding is very much to the same effect:

[31] There is no magic to the term “selection patent”. . . . The Patent Act does not refer to selection patents and the jurisprudence is clear that a selection patent does not differ in substance or form from other patents.

[32] A selection patent is subject to the same requirements and vulnerable to the same attacks as any other patent, including attacks based on anticipation and obviousness. [T]he failure of a judge to characterize a patent one way or another . . . is not an error of law. Put otherwise, a finding that the characteristics of a selection patent have, or have not, been met, “does not constitute an independent basis upon which to attack the validity of the patent”

[34] As noted, the validity analysis does not change depending on whether the patent was formally classified as a selection patent or not.

[35] There is no divergence between the requirements for a valid patent claim depending on whether it is found in a selection patent or not.

This seems to me to be entirely right.

But there is a loose end. Rennie JA did not directly explain how his holding could be reconciled with the fact that the SCC in Sanofi 2008 SCC 61 [10]–[11] endorsed the three factors set out by Maugham J in IG Farbenindustrie (1930) 47 RPC 289 (Ch). I’ll make an attempt.

The obvious way to reconcile the IG Farbenindustrie factors with the view that there is nothing special about selection patents is to suggest that those factors are simply an alternative articulation of the standard analysis in the specific context of selection patents. This was evidently Rennie JA’s view: “classification contextualizes what specific claims profess to do while also making it easier to compare the facts of the particular case before the Court to other previous fact scenarios” [33].

This was also apparently the view of Maugham J: “I think it would be unwise to endeavour to state in definite language all the conditions on which a selection patent must depend; for after all a selection patent does not in its nature differ from any other patent and is open to attack on the usual grounds of want of subject-matter, want of utility, want of novelty and so forth” (322)’ the same view was also suggested in Sanofi [9], quoting part of this passage.

With that in mind, consider the factors themselves, as set out in Sanofi [10]:

1. There must be a substantial advantage to be secured or disadvantage to be avoided by the use of the selected members.

While the tripartite IG Farbenindustrie test was often referred to, this first factor was undoubtedly the most important, as it was the factor that was normally actually applied (along with Maugham J’s statement at 321, which is not part of the tripartite test as such, that “the selected compounds have not been made before, or the patent would fail for want of novelty.”) It is therefore fortunate that this factor is easy to reconcile with a standard analysis. It was explicit in both IG Farbenindustrie and Sanofi that this is a reflection of the inventive step requirement: “If the selected compounds. . . possess a special property of unexpected character. . . I cannot see that the inventive step essentially differs from the step involved in producing a new result by a new combination of well-known parts . . . in mechanics in the construction of a new machine” (321), quoted in part in Sanofi [9]; “if for practical purposes it is not obvious to skilled chemists in the state of chemical knowledge existing at the date of a selection patent that the selected components possess a special property, there is then, or at least there may be, a sufficient ‘inventive step’ to support the Patent” (322). The idea is that if the originating patent disclosed a large class of compounds and disclosed that they are all, eg antipsychotics with moderate to severe side-effects, there is nothing inventive in pulling one at random out of the class and establishing that it is an antipsychotic with moderate to severe side-effects. An arbitrary selection is not inventive.

The second factor is as follows:

2. The whole of the selected members . . . possess the advantage in question.

This is trickier. Maugham J stated that if this is not satisfied, “the patent would be misleading and would also fail for insufficiency and non-utility.” Unfortunately, Maugham J did not provide any further details, and it is not immediately clear how the patent would fail in light of English patent law of the day. In modern Canadian law, “misleading” patents are dealt with under s 53, which now has a well-developed body of jurisprudence. To the extent that the second factor was intended to address such problems, it must considered to be displaced by the statutory provision of the Canadian Act. I have to admit it is not clear to me why the patent would be insufficient; a failure of the second factor would not affect the classic “how to make” enablement. There are other aspects of the English sufficiency law of the day which Maugham J might have had in mind, eg ambiguity. The law of utility has also developed considerably since 1930, and arguably if the genus claim in the originating patent was valid, all the claimed compounds which it encompassed must have been useful, and it is hard to see how they would become less useful, simply because some other compounds are more useful.

With all that said, it is clear that Maugham J considered his second factor to be nothing more than the application of general principles to the context of selection patents. To the extent that modern Canadian law has diverged from century old English law, then it seems plain that our modern law should govern; it would be wrong to regress—or worse, displace statutory provisions—by adhering to a test for selection patents that was based on century old English law.

On to the third factor:

3. The selection must be in respect of a quality of a special character peculiar to the selected group.

Maugham J at 323 indicated that this was not based on established principles, but was rather his own analysis. It not clear whether this was ever good law. I am not aware of any case which has actually applied this factor to hold a patent invalid. Moreover, this factor was also criticized on substantive grounds by the EWCA in Dr Reddy’s [2009] EWCA Civ 1362 [39], which also held that the whole IG Farbenindustrie test was no longer part of English law.

None of this conflicts with the SCC holding in Sanofi. The only one of the three factors actually applied was the first—see eg [31], [31], [41]— which, as discussed above, is clearly based on the standard non-obviousness requirement. Moreover, while the SCC in Sanofi certainly spoke favourably of Maugham J’s analysis, the Court did not go so far as to say that the tripartite test had to be satisfied as a matter of law. Rather, the SCC stated that it is “a useful starting point for the analysis to be conducted in this case.” [11]. Experience has shown that it is not a particularly useful starting point in most other cases. It is not contrary to Sanofi to recognize that fact.

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