The Supreme Court of Canada Knocked Down the "Promise Doctrine” for Determining Utility


By Suzanne Hof and Poonam Tauh, June 30th, 2017

Today, the Supreme Court of Canada, in AstraZeneca Canada Inc. v. Apotex Inc., 2017 SCC 36, has determined that the Promise Doctrine is not the correct method of determining whether the utility requirement under s. 2 of the Patent Act is met, and upheld the utility of the appelants’ 2,139,653 patent.

The Promise Doctrine holds that if a patentee’s patent application promises a specific utility, only if that promise is fulfilled, can the invention have the requisite utility, but where no specific utility is promised, a mere scintilla of utility will suffice.

The Court has found that the Promise Doctrine is excessively onerous in two ways: (1) it determines the standard of utility that is required of a patent by reference to the promises expressed in the patent; and (2) where there are multiple expressed promises of utility, it requires that all be fulfilled for a patent to be valid.

First, the Court found that the Promise Doctrine conflates s. 2 of the Act (which requires that an invention be “useful”) and s. 27(3) (which requires disclosure of an invention’s “operation or use”), by inappropriately requiring that to satisfy the utility requirement in s. 2, any disclosed use (by virtue of s. 27(3)) be demonstrated or soundly predicted at the time of filing. If that is not done successfully, the entire patent is invalid, as the pre-condition for patentability — an invention under s. 2 of the Act — has not been fulfilled.

Second, the Court found that the Promise Doctrine runs counter to the words of the Act by requiring that where multiple promised uses are expressed, they all must be satisfied for the patent to meet the utility requirement in s. 2.

The Court established the correct approach to utility as follows:

  • [54] To determine whether a patent discloses an invention with sufficient utility under s. 2, courts should undertake the following analysis. First, courts must identify the subject-matter of the invention as claimed in the patent. Second, courts must ask whether that subject-matter is useful — is it capable of a practical purpose (i.e. an actual result)?
  • [55] The Act does not prescribe the degree or quantum of usefulness required, or that every potential use be realized — a scintilla of utility will do. A single use related to the nature of the subject-matter is sufficient, and the utility must be established by either demonstration or sound prediction as of the filing date.

With respect to the ‘653 patent, the Court stated that the utility of the optically pure salts of the enantiomer of omeprazole as a proton pump inhibitor to reduce production of gastric acid (the subject matter of the ‘653 patent) was soundly predicted. The ‘653 patent is therefore not invalid for want of utility."

Today’s long-awaited decision places Canada back in-line with international standards, and provides greater certainty to patentees and to patent prosecutors and litigators.


For more information please contact:

Suzanne Hof, Senior Patent Agent

T: 613.801.0510

E: This e-mail address is being protected from spambots. You need JavaScript enabled to view it.


Poonam Tauh, Senior Patent Agent

T: 403.800.9018

E: This e-mail address is being protected from spambots. You need JavaScript enabled to view it.


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