Patents: Supreme Court of Canada Abolishes the "Promise Doctrine"

By: Susan L. Rancourt <Srancourt@parlee.com>

On June 30, 2017, the Supreme Court of Canada released its highly anticipated patent decision regarding Canada’s so-called “Promise Doctrine’”. The Promise Doctrine was used to assess whether a patented invention satisfied the “utility” requirement in Canada. It involved reviewing a patent to identify what “promises” were made as to the utility of the invention, and then assessing whether those promises were actually met. All “promised utilities” had to be either (a) demonstrated or (b) soundly predicted, as of the filing date. If that was not the case, the utility requirement was not satisfied and the patent was deemed invalid. This decision abolished the Promise Doctrine, stating that it was “unsound” and “not good law” (2017 SCC 36).

AstraZeneca patented an optically pure salt of esomeprazole, a proton pump inhibitor sold under the brand name NEXIUM (Canadian patent 2,139,653). Apotex was sued by AstraZeneca for infringement of this patent, and counter-claimed that the patent was invalid. At trial, although the patent was found to be both novel and non-obvious, it was deemed invalid for lack utility, for not fulfilling one of the two promises of utility in the patent.  While the promised usefulness as a proton pump inhibitor was soundly predicted as of the filing date, the promise of improved pharmacokinetic and metabolic properties was not. The Court of Appeal upheld this finding, and this decision was appealed to the Supreme Court of Canada.

The Supreme Court’s decision was succinct and decisive, stating that “promises are not the yardstick against which utility is to be measured”. To require that all multiple uses be met for the patent’s validity to be upheld has the potential for unfair consequences, as an otherwise useful invention will be deprived of patent protection because not every promised use was demonstrated or soundly predicted by the filing date. The correct approach to assessing utility is to: (a) identify the subject-matter of the invention as claimed in the patent; and (b) ask whether that subject-matter is useful, that is, capable of a practical purpose. A scintilla of utility will do, and any single use that is related to the nature of the subject-matter claimed, and which is demonstrated or soundly predicted by the filing date, will satisfy the utility requirement. One note of caution, however - overpromising is a mischief – but it is one that is appropriately dealt with under other sections of the Canadian Patent Act.