Tuesday, July 17, 2018

Not Necessary to Decide Whether the Patent at Issue Is a Selection Patent

Apotex Inc v Shire LLC 2018 FC 637 Fothergill J
            2,527,646 / lisdexamfetamine [LDX] / VYVANSE / NOC

Shire’s invention at issue in this consolidated impeachment action and prohibition application [20] relates to the compound L-lysine-d-amphetamine aka lisdexamfetamine aka LDX, its pharmaceutical compositions and it use for treating ADHD [34]-[40]. Fothergill J found the 646 patent to be valid and not infringed by Apotex’s activities to date, on the basis of the defence of experimental or regulatory use, but he granted the order of prohibition on the basis that the patent would be infringed if Apotex were to obtain an NOC and market Apo-lisdexamfetamine. The decision raises some interesting issues relating to selection patents and obviousness, though they were not dispositive, and in the end the decision turned largely on the facts.

Amphetamines have long been used to treat ADHD, but they can be abused by snorting or injection [28]. There was therefore a need for a therapeutically effective abuse-resistant dosage form of amphetamine. LDX provides a solution to that problem in the form of a prodrug, namely an amphetamine covalently attached to a chemical moiety which is transformed into the active amphetamine in the body through a time-dependent process of hydrolysis, resulting in an extended release form that cannot be effectively circumvented by snorting or injection [31]. The claims as construed by Fothergill J were directly specifically to a conjugate of the amino acid L-lysine bound to d-amphetamine [74].

The main validity attack was based on AU Patent No 54168/65, which disclosed “a very large class of d-, l-, and dl-amphetamine amino acid conjugates, both protected and unprotected” [104]. None of the specific examples disclosed LDX itself [105]. The parties debated whether the 646 patent was a selection over the 168 patent [88], with Apotex arguing in particular that the 646 patent provided “insufficient description of its advantages over the purported genus patent to be classified as a selection from AU 168, citing Hoffman-La Roche Ltd v Apotex Inc, 2013 FC 718.” I am very pleased that Fothergill J cited my blog post “Time to Abandon the Doctrine of Selection Patents?” which critiqued that aspect of Hoffman-La Roche, saying that those criticisms “may be reason to approach Hoffman-La Roche with caution” [96]. (I’d point out that my post Genus Anticipates Species is perhaps even more directly relevant to the anticipation analysis in Hoffman-La Roche, as that is the post in which I argued that Hoffman-La Roche cannot be distinguished from Sanofi 2008 SCC 61.)

More importantly, in the post cited by Fothergill J, I had argued that the selection patent doctrine was arguably generating more heat than light, and it might be time to abandon the doctrine entirely. Forthergill J stated that “Professor Siebrasse’s general remarks regarding this potentially confusing area of patent law are worth bearing in mind,” and he went on to emphasize that

[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.

This is a strong statement, though in the end he held that nothing turned on the point, so it was unnecessary for him to decide whether the 646 patent was a selection patent [98].

On the facts, Fothergill J concluded that the AU 168 patent did not anticipate the 646 patent, in part because the AU 168 patent did not disclose the mechanism or relevant properties of the prodrug, or even that it was a prodrug [106]-[108]. This reasoning is consistent with and tracks the analysis in Sanofi 2008 SCC 61 [38], [40]-[41], which emphasized disclosure of the special properties of the species. I would suggest that there is another route to the same end, which is that the genus does not anticipate the species unless the genus contains an individualised description of the species. That is the European position: see Dr Reddy’s [2009] EWCA Civ 1362 [23]-[33]. In my view, that is entirely consistent with established Canadian principles: a disclosure of genus which does not individually identify a species would not allow a skilled person to arrive at the species “in every case and without possibility of error” (Beloit 8 CPR(3d) 289, 297 (FCA)), nor would practising the genus necessarily result in infringement of the species patent. A person who has disclosed a genus and “planted his flag” by disclosing some representative species, does not plant a flag at every species within the genus: to plant a flag in L'Anse aux Meadows is to plant a flag in North America, but it is not the same as planting a flag in San Diego. I’d suggest the converse is also true. If the genus patent had individually disclosed a compound, that compound could not be the subject of a new claim as such, even if it’s unique properties were not disclosed, for the same reason that a party who discovered a new use for a known compound can claim the new use, but not the compound per se. But all that is an aside, given that in this case the claimed species was not individually disclosed.

Turning to obviousness, Forthergill J noted that the FCA in Ciba v SNF 2017 FCA 225 (blogged here) had raised questions as to the role of the “inventive concept” in the obviousness analysis [115]. Apotex went so far as to argue that “following Ciba, ‘inventive concept’ should no longer be used in the obviousness analysis, pending clarification of its meaning by the Supreme Court. Rather, the question of obviousness should be determined by reference to the claims alone” [116]. Fothergill J rejected this, noting that as a matter of stare decisis, Ciba cannot be understood to have overruled the SCC decision in Sanofi [117]. Moreover, as Fothergill J noted, in this particular case, “the inventive concept may be grasped without difficulty, and there is no danger of distraction or engaging in unnecessary satellite debate” [117]. While the FCA in Ciba v SNF was certainly very critical of the role that is sometimes played by the inventive concept, Forthergill J’s approach nonetheless strikes me as being consistent with both Ciba v SNF and Sanofi. Ciba v SNF counseled particularly strongly against the uncertainty which might arise from parsing the disclosure in a search for the inventive concept [74], but the Court did not say that the “inventive concept” should never be used. 

This does not detract from the criticisms of the role of the "inventive concept" raised by the Court in Ciba; it is only to say that they did not arise in this particular case. I have thought for some time that the European problem-solution approach may be a way of resolving some of those problems, and that it is consistent with the traditional Canadian approach to obviousness. Consequently, I found it particularly interesting to see Shire suggesting a European-style “problem-solution” analysis might be “viable” and consistent with Sanofi [120]. The Court of Appeal in Ciba suggested that it will be up to the SCC to develop “a workable definition of the inventive concept” [77]. But given that the SCC in Sanofi did not provide a workable definition, perhaps it is open to the Federal Courts to fill that gap, so long as it is done in a manner that is consistent with Sanofi and prior Canadian law.

Finally, on a minor point of interest, the claim construction adopted by Fothergill J implied that some claims were redundant, describing exactly the same compound either verbally or visually. Fothergill J noted that “[a]s a general rule, claims should be construed to avoid redundancy. However, claims may be repeated, and courts may even read claims as redundant when it is reasonable to do so,” and in this case he held that the best reading was to accept the redundancy [75]. It seems likely that the reason for the redundancy was an excess of caution—the drafter was likely worried that either the verbal or visual representation might be misconstrued, and so included both.

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