Patent Law Update: Supreme Court of Canada Rejects the “Promise Doctrine”

Jun 30 2017

In a unanimous and relatively short decision, the Supreme Court of Canada firmly rejected the “Promise Doctrine”, which has been frequently invoked to invalidate patents on the basis of a lack of utility.

This decision in AstraZeneca Canada Inc. v. Apotex Inc., 2017 SCC 36 reverses over a decade of previous case law, which saw numerous patents declared invalid in Canada.  Under the (now rejected) “promise doctrine”, the utility of an invention could be measured against statements in the patent disclosure regarding the uses of the invention, with the patent being invalid if even one of those promises was not established or soundly predictable from the information in the description. The doctrine had particular impact on pharmaceutical patents, which tend to identify medical uses for the invention without providing clinical data in the description.

The Court concluded that the “Promise Doctrine” conflated the requirements for sufficiency and utility, which should be separate inquiries. The Court also held that a single use of the invention is sufficient to establish utility, even if this use has a “mere scintilla” of utility, so long as that use is related to the subject matter of the invention.

The Astrazeneca decision sets out a two-part test for utility in Canada, which requires the Courts to: (1) identify the subject matter of the claims and (2) determine whether at least one practical use related to that subject matter has been demonstrated or soundly predicted as of the filing date (even if that amounts to only ‘a mere scintilla’ of utility).  The Court also re-affirmed the principle that there is no obligation to disclose the utility of the invention within the description.

The case at hand involved AstraZeneca’s patent no. 2,139,653, which was directed to optically pure salts of esomeprazole, a proton pump inhibitor (PPI). This drug was said to be useful for reducing gastric acid and reflux esophagitis, and for treating related maladies. The trial and appeal Courts had previously concluded that the patent explicitly promised that this drug would work more effectively for a wider range of persons than previous drugs, with less variation in patient responses, and that this promise was unfulfilled. The Supreme Court rejected this analysis and found that the drug would work as a PPI, which was sufficiently related to the subject-matter of the patent so as to make it useful within the meaning of the Patent Act. As a result, the patent was found to be valid.

The decision is welcome news to patentees in Canada, as it brings more certainty to the law and aligns Canada with the standard for utility of most other countries.

For more information, contact one of our professionals.

Authors: Andrew Montague (former associate)

This article is for information purposes only and does not constitute legal or professional advice.

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Tags: Biotechnology & Pharmaceutical, Ken Ma, Patent Act