In this case, involving the medicine donezepil, Justice Hughes, for the Court, granted an order of prohibition in favour of the applicant and found that the allegation of lack of utility/sound prediction was not justified.

The patent relates to a new compound said to be useful in the treatment of senile dementia. By the filing date, testing in humans had yet to be conducted. The Court agreed that the threshold test for utility is low.

Further, the Court commented on claim construction and utility and noted that a compound claim does not have a utility requirement beyond the promise in the specification. The Court found that it was improper to cumulatively combine each statement in the specification relating to utility in construing the promise of the patent. With respect to utility of the use claim, the specific use set out in the claim would have to be shown to be useful or be a sound prediction. Thus, a claim by claim analysis ought to be done.

After reciting much law on (i) the promise of the patent, (ii) utility, (iii) the difference between compound and use claims, and (iv) the perils of expert testimony on the issue of construction, the Court appears to have accepted Pfizer's expert's position: (1) the promise of the patent is that the compounds are AChE inhibitors in rats and mice - this is sufficient to satisfy the utility requirements for the compound claim; and (2) with respect to the claim for the use of the compound, the Court found that the 3 part test for a sound prediction of utility was met.

In terms of the 3 part test for sound prediction set out in AZT, the Court comments

  1. factual basis - on the issue of whether the factual basis for a prediction has to be in a patent, the Court finds, referencing the AZT case of the Supreme Court, that the factual basis has to be present in the patent. Here, the patent referred to having made and tested donezepil.
  2. articulable and sound line of reasoning - the Court reiterated the test set out by the Court of Appeal in the olanzapine case, namely, that there must be a prima facie reasonable inference and confirmed also that this may be met by a reasonable theory of the day (para 244).
  3. proper disclosure - if a patent states that a useful result has been achieved then there is no requirement to demonstrate utility in the specification (para. 225).

Also, of interest is that the Court once again reiterated that notices of allegation cannot be amended and suggested that it may be preferable to proceed in these matters by way of action.

The full text of the decision can be found at: