Canada - The Sound Prediction Doctrine
The appropriate scope of protection for an invention has become an important topic in recent years as new technologies have developed and the requirement to avoid reclaiming the prior art normally imposes limitations on the scope of claim that one can assert has become less effective as a result of the paucity of prior art in some of these new technologies. Thirty-six years ago in deciding the proper scope of claim to be given for a new class of phenothiazines defined by a generic formula encompassing a large number of compounds, the English patent judge held, in the case of Olin Mathiesen Chemical Corporation v. Biorex Laboratories Ltd., that, if it is possible for the patentee to make a sound prediction and to frame a claim which does not go beyond the limits within which the prediction remains sound, then he is entitled to do so.
The concept of sound prediction was taken up by the Canadian Supreme Court in 1979 in Monsanto Co. v. Commissioner of Patents and revisited by the Supreme Court in 2002 in Apotex Inc. v. Wellcome Foundation Ltd. in which the court held that the test for sound prediction has three components:
1. There must be a factual basis for the prediction. What factual basis will suffice will depend on the nature of the invention.
2. The inventor must have, at the date of the patent application, an articulate and “sound” line of reasoning from which the desired result can be inferred from the factual basis. What line of reasoning will be legitimate will depend on the subject matter.
3. There must be proper disclosure. It is generally not necessary for an inventor to provide a theory of why the invention works; practical readers merely want to know that it does work and how to work it.
In Merck & Co v. Apotex Inc., the application of these principles has led to the trial court finding a Merck patent relating to a high dosage form of FOSAMAX®, which aimed at reducing damage to the esophagus, as being invalid as lacking utility as disclosed. The patent contained no clinical data obtained from humans. Dog data were included but criticized as being inadequate to justify a conclusion that use of higher than usual dosages of the active ingredient administered less frequently than was the prior custom would reduce esophagal damage in humans as was claimed in the patent. The judge agreed that increased safety with maintained efficacy could not be deduced from the data and so that patent articulated no sound prediction of utility and was invalid for this reason.
