The Patentability of Pharmaceutical Dosage Regimes in Canada

Abstract:

In its 1974 decision in Tennessee Eastman Co. v. Canada (Commissioner of Patents), the Supreme Court of Canada held that methods of medical treatment constituted unpatentable subject matter. The Court largely based its decision on what was then s. 41 of the Patent Act, a provision repealed in 1991. Whether the prohibition on patenting methods of medical treatment remains justified under the current Patent Act has generally received little attention, because it has been possible to claim most inventions in this area, which typically relate to new applications for medicines, as a use rather than a method. However, a number of recent Canadian court decisions have indicated that patent claims directed to the use of pharmaceutical products in accordance with a dosage regime may contravene the method of treatment prohibition. This is, perhaps, surprising in view of the patentability of such claims in the European Patent Office, despite the express statutory prohibition on patenting methods of medical treatment under the European Patent Convention. This article reviews the history of the method of treatment prohibition in Canada and explores its underlying rationale. The patentability of methods of medical treatment, particularly with respect to pharmaceutical dosage regimes, is compared among Canada, the United States, and Europe. Suggested practices for prosecution of Canadian patent applications in this field are provided.