The False Doctrine of False Promise

The emergence of the “promise of the patent” doctrine is an important recent development in Canadian patent law, which primarily impacts pharmaceutical patents. The doctrine holds that if the specification sets out an explicit “promise,” the utility requirement will be satisfied only if the claimed invention delivers on that promise. In practice, the promise of the patent, as set out in the disclosure, is now almost invariably the standard for assessing utility of a pharmaceutical patent. The result is that a patent may be held invalid for lack of utility, notwithstanding that the disclosed invention has sufficient utility to support a valid patent. This article shows that the doctrine originated in English law at a time when the grant of the patent was a discretionary exercise of the royal prerogative, so that the Crown might properly refuse to grant a patent even though it would be upheld by the courts if granted. Consequently, the patent was granted on the basis of all representations made by the applicant, and the promise of the patent doctrine reflected an unwillingness of the courts to second-guess the Crown in the exercise of its prerogative. This article argues that the doctrine is inconsistent with the Canadian Patent Act, under which an applicant is entitled to a patent as a matter of right if the invention satisfies the statutory criteria