Methods of Medical Treatment: Still Not an “Invention” in Canada

On January 27, 2014, the Federal Court of Appeal in Novartis Pharmaceuticals Canada Inc. v. Cobalt Pharmaceuticals Co., 2014 FCA 17 (Novartis), upheld the Federal Court’s denial of an application for a prohibition order under the Canadian Patented Medicines (Notice of Compliance) Regulations on the basis that the impugned patent was directed to a method of medical treatment.  With this third decision1 on alleged methods of medical treatment in the past year alone, Canadian courts continue to hold methods of medical treatment to be unpatentable, while providing only limited guidance about the limits of permissible claiming. 

In Novartis, the claims at issue were directed to a particular frequency of dosing zoledronic acid to treat osteoporosis, namely intermittent administration about once a year. For example, claim 16 was directed to “use of zoledronic acid for the treatment of postmenopausal osteoporosis wherein the zoledronic acid … is in a unit dosage form of about 5 mg which is administered intermittently, with a period of about one year between the first and each subsequent administration, wherein each administration is intravenous.”  Of note, the Federal Court had found that the dosing frequency was the sole aspect of the invention that made it not obvious.  The issue, therefore, was whether a dosing frequency falls within the scope of patentable subject matter set out in the definition of “invention” in section 2 of the Patent Act.

Consistent with European practice, Canadian courts have long found methods of medical treatment to be unpatentable, even after the Patent Act’s former prohibition against patenting drug substances was repealed. Relying on the 1972 decision of the Supreme Court of Canada in Tennessee Eastman Company v. Commissioner of Patents, [1974] S.C.R. 111, which involved a surgical method for joining incisions by applying certain compounds, Canadian courts have found the following subject matter, for example, to be unpatentable: dosage ranges dependent on a patient’s weight,2 a titration regime,3 and use claims where components and dosages need to be selected.4 The courts’ rationale appears to be that Canadian patents ought not interfere with the ability of physicians to exercise their skill and judgment.

In Novartis, the Federal Court of Appeal had the opportunity to clarify what exactly amounts to an unpatentable method of medical treatment.  Unfortunately, the four paragraph decision does little more than affirm the decision below.  Under Canadian case law, therefore, it is settled that vendible products, such as pharmaceutical dosage forms, are patentable subject matter.  Claims as to the use of a drug to treat a medical condition are also allowed, whether worded as such or as Swiss-type claims (“the use of drug X in the manufacture of a medicament to treat condition Y”5).  By contrast, claims directed to subject matter falling within the skill of a medical professional have been found improper.  In practice, however, this distinction may be difficult to draw in respect of claims that include both a vendible product (e.g., a dosage form) and subject matter related to the exercise of professional judgment (e.g., a dosing regimen). In these circumstances, Canadian courts scrutinize the patent specification’s language to determine if a claim to a commercial product requires skill to administer it.  If so, the claim will likely be invalid.  In the result, a claim to “the substance X in the form of a 5 mg tablet for the treatment of Y” is proper, but a claim to “the use of substance X in a dosage range between A and B for the treatment of X” probably is not.  

The Novartis case confirms that Canadian patent applicants should use caution in relying on therapeutic dosing limitations to distinguish the prior art.  Such limitations could be argued to fall within the skill and judgment of a medical practitioner, and invalidate the claims at issue. 

1 See the Federal Court’s decision in Novartis Pharmaceuticals Canada Inc. v. Cobalt Pharmaceuticals Co., 2013 FC 985, and Bayer Inc. v. Cobalt Pharmaceuticals Co., 2013 FC 1061.

2 Axcan Pharma v. Pharmascience Inc., 2006 FC 527.

3 Janssen Inc. v. Mylan Pharmaceuticals ULC, 2010 FC 1123.

4 Bayer Inc. v. Cobalt Pharmaceuticals Company, 2013 FC 1061.

5 For a detailed review on Swiss-style claims, see Merck & Co., Inc. v Pharmascience Inc, 2010 FC 510.