Patentability In Canada: Federal Court Of Appeal Questions The Fixed Dosage Amount vs Dosage Range Distinction

In Canada, claims to new uses based on the discovery of "hitherto unrecognized properties" constitute patentable subject matter.1 Use claims in the context of pharmaceutical inventions are also allowed; claims to the "use in the treatment or prophylaxis" of AIDS were unanimously held by the Supreme Court to be patentable subject matter and not an impermissible "method of medical treatment".2 Likewise, claims to the use of compound A at fixed dosage amount/dosing schedule B to treat disease C are patentable.3

It has thus been to the great frustration of innovative companies that courts, and some examiners at the Patent Office, consider that use claims that contain a limitation pertaining to a dosage range or dosing schedule are unpatentable on the purported basis that they interfere with a physician's ability to practice and constitute a method of medical treatment.4 The recent Federal Court of Appeal ("FCA") decision in Hospira Healthcare v The Kennedy Trust [Remicade/Inflectra]5 considers the issue and candidly acknowledges some of the shortcomings with the current state of affairs.

Background

Methods of medical treatment are currently considered to constitute unpatentable subject-matter in Canada. The provenance of this restriction is the Supreme Court of Canada's decision in Tennessee Eastman v Commissioner of Patents.6 The Court in Tennessee Eastman founded the restriction on a now-repealed provision of the Patent Act (formerly section 41(1)). Given this, in 2016 the Federal Court of Appeal and academic commentary called for the Supreme Court to revisit this doctrine and whether it has any statutory basis (discussed here).

More recent jurisprudence has drawn seemingly arbitrary distinctions between different types of use claims, with some being permitted and others objected to under the method of medical treatment prohibition. Since the repeal of section 41(1), Courts have distinguished between claims that ostensibly relate to professional skills and allegedly "fence in" an area of medical treatment/physician autonomy from those that relate to "vendible products", "commercial offerings", or "trade, industry or commerce".

Applying this distinction has led to the strange situation described in the introduction. Broader "use of compound X for the treatment of condition Y" claims are considered patentable subject-matter while claims that add a restriction in terms of a dosage range or a dosing schedule, and which are thus narrower in scope...