Promise Doctrine

In a unanimous decision, the Supreme Court held today that the promise doctrine is not the correct approach to determine whether a patent has sufficient utility. As a result, the lower court decisions finding the patent at issue directed to Esomeprazole/Nexium invalid for want of utility, were set aside.

In the decision, AstraZeneca Canada Inc. v. Apotex Inc., 2017 SCC 36 (on appeal from 2014 FC 638 and 2015 FCA 158), Rowe J. wrote:

[2] … Unquestionably, a patent is invalid if it lacks utility. However, for the reasons that follow, I conclude the application of the Promise Doctrine is not the correct approach to determine whether a patent has sufficient utility.

[35] Thus, the origin and justification of the promise doctrine in English law was the “unwillingness of the courts to second-guess the Crown in the exercise of its discretion” (Siebrasse, at p. 17; Bloxam v. Elsee (1827), 6 B. & C. 169, 108 E.R. 415 (K.B.)). While the False Promise Doctrine is now extinct in the English law, it has found a new home in the Federal Courts’ jurisprudence as the “promise of the patent” doctrine.

[36] This doctrine, however, is unsound. It is an interpretation of the utility requirement that is incongruent with both the words and the scheme of the Patent Act .

[46] The scheme of the Act treats the mischief of overpromising in multiple ways. There are consequences for failing to properly disclose an invention by claiming, for instance, that you have invented more than you have. A disclosure which is not correct and full, or states an unsubstantiated use or operation of the invention, may be found to fail to fulfill the requirements of s. 27(3) . An overly broad claim may be declared invalid; however, under the operation of s. 58  of the Patent Act , remaining valid claims can be given effect. As well, this mischief may result in a patent being void under s. 53 of the Act, where overpromising in a specification amounts to an omission or addition that is “willfully made for the purpose of misleading”.

[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 (AZT, at para. 56).