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01 June 2015
In patent claims, Markush groups define claimed subject matter in a form such as "the group consisting of A, B and C", whereas alternatives may be recited in a form such as "A, B or C". In upholding the patent at issue in Eli Lilly Canada Inc v Mylan Pharmaceuticals ULC (2015 FC 17), the Federal Court considered the validity of claims that recite Markush groups compared with claims to alternatives.
The Patent Act does not explicitly address Markush groups, but does explicitly address claimed alternatives, as follows:
"27. (5) For greater certainty, 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" (emphasis added).
The aforementioned Sections 2, 28.1 to 28.3 and 78.3 of the Patent Act relate to substantive requirements for patentability, such as utility, novelty and non-obviousness.
In Abbott Laboratories v Canada (Minister of Health) (2005 FC 1095) (Abbott I) the Federal Court distinguished Markush groups from alternatives and defined a Markush claim as a claim to the entire group. In Abbott I the Federal Court concluded that an entire Markush claim was invalid because some (but not all) of the solvents in the Markush group lacked utility.
Section 27(5) of the Patent Act could be interpreted to mean that if the solvents in the Abbott I decision had been defined as alternatives instead of as a Markush group, then each solvent would be a separate claim and the claims to solvents that had utility could still be valid. If that interpretation of Section 27(5) were correct, then alternatives might be stronger than Markush claims.
However, in Abbott Laboratories v Canada (Minister of Health) (2005 FC 1332) (Abbott II) the Federal Court considered the same Markush claim that was at issue in Abbott I and stated that even if the claim had recited an alternative as contemplated by Section 27(5), the whole claim would still fail if any of the alternatives were not patentable. The court reached that conclusion by characterising Section 27(5) as "principally an administrative provision for purposes of a patent application".
Together, the Abbott I and Abbott II decisions seem to suggest that Markush claims and claims to alternatives will both fail entirely if they include any invalid embodiments.
However, the more recent Eli Lilly v Mylan decision suggests that Markush terminology may be the better choice. In that decision, the Federal Court considered Claim 2 in Canadian Patent 2,226,784, which recited the following:
"2. A pharmaceutical composition for the curative or prophylactic treatment of erectile dysfunction in a male animal, comprising 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,
together with a pharmaceutically acceptable diluent or carrier."
The issued claim included chemical formulae, which for simplicity have been replaced by "[tadalafil]" and "[3-methyl tadalafil]" in the excerpt above.
Mylan argued that 3-methyl tadalafil lacked utility, so the court considered whether a lack of utility of 3-methyl tadalafil would affect the validity of Claim 2. Because Claim 2 defined a "group consisting of" different compounds that are joined with "and", the court characterised it as a Markush claim, rather than a claim directed to alternatives that would be subject to Section 27(5) of the Patent Act.
The court reaffirmed its previous interpretation of Section 27(5) in Abbott II – that if a claim defines alternatives, the entire claim fails if one of the alternatives is invalid. Because Claim 2 was a Markush claim, rather than a claim to alternatives, the court concluded that Section 27(5) did not apply and that Claim 2 would not be invalid for lack of utility, even if 3-methyl tadalafil did lack utility. Therefore, the court did not actually decide whether 3-methyl tadalafil lacked utility. The court's approach in Eli Lilly v Mylan appears to be contrary to Abbott I, in which the Federal Court rejected a Markush claim that included both valid and invalid embodiments.
The Eli Lilly v Mylan decision has been appealed to the Federal Court of Appeal, which may clarify the significance of claims to Markush groups and the impact of Section 27(5).
In certain situations, Markush groups are important forms for defining claimed genera. Patent applicants in jurisdictions where excess claims fees are charged may also define Markush groups or alternatives in order to reduce or avoid such fees. However, Canadian patent applications do not incur excess claims fees; reciting separate elements in separate claims – where practical – may be prudent, in order to avoid the ongoing uncertainty regarding Markush groups and alternatives.
For further information on this topic please contact Jonas Gifford at Smart & Biggar/Fetherstonhaugh by telephone (+1 604 682 7780) or email (firstname.lastname@example.org).The Smart & Biggar/Fetherstonhaugh website can be accessed atwww.smart-biggar.ca.
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