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.