In a unanimous decision released on December 5, 2002, the Supreme Court of Canada has upheld the validity of the AZT patent held by the Wellcome Foundation Limited and Glaxo Wellcome Inc. (Glaxo/Wellcome). The decision is of particular interest for its detailed review of the requirement of utility in Canadian patent law and the extent to which the doctrine of sound prediction can be relied upon in supporting the utility of a patent claim.
In the early 1980s, testing of the previously synthesised compound AZT on murine retroviruses led Glaxo/Wellcome researchers to believe the compound might have a use as a treatment for HIV. Glaxo sent the compound to two scientists at the U.S. National Institutes of Health (NIH) for further testing. Based on the success of those in vitro tests on human cells, Glaxo/Wellcome submitted a patent application to the U.K. patent office, and subsequently filed a patent application in Canada, claiming priority from the U.K. application. In 1990, the generic manufacturers Apotex and Novopharm instituted an action in Canada against Glaxo/Wellcome, claiming that the patent at issue was invalid.
The central issue of the case was a challenge to validity based on the argument that the necessary utility had not been established as of the priority date of the Canadian patent -- the filing of the U.K. application on March 16, 1985. The specific allegation was that the compound's prophylactic properties, as opposed to its treatment properties, had not been established as of that date. Validity was also challenged on the basis of a failure to name all of the inventors, because Glaxo/Wellcome did not name as co-inventors two individuals from the NIH who carried out in vitro testing of AZT in a human cell line.
Utility
Section 2 of the Canadian Patent Act requires that an invention be "new and useful." The Court confirmed that a claimed invention must have "utility" i.e., it must be useful for the purpose claimed. The Court stated that where the new use is the invention, "the utility required for patentability must, as of the priority date, either be demonstrated or be a sound prediction based on the information and expertise then available."
The Doctrine of Sound Prediction
The doctrine of sound prediction has been established in Canadian law for some time. However, the Court, in this decision, has extensively reviewed the history, scope and applicability of the doctrine, noting that it balances the public interest in having early disclosure of new and useful inventions prior to full verification of utility, while avoiding a grant of patent rights based on the disclosure of speculative information. The Court identified a three-component requirement of the doctrine:
- There must be a factual basis for the prediction;
- The inventor must have at the date of the patent application an articulable and "sound" line of reasoning from which the desired result can be inferred from the factual basis; and
- There must be proper disclosure of the foregoing.
The Court was careful to note that the soundness of the prediction is a question of fact and each case will turn on the particular details associated with the discipline to which the subject matter relates, and the evidence in respect thereof.
The Court reaffirmed a long-standing position that sound prediction will not successfully support a patent claim if either the prediction at the date of the application was not sound or, irrespective of the soundness of the prediction, there is evidence of lack of utility in respect of some of the areas covered by the claim.
Sound Prediction and Pharmaceuticals
The Court has provided noteworthy clarification of certain issues that are of particular relevance to the pharmaceutical field.
- The Court recognized comments from earlier jurisprudence that the predictability of chemical reactions differed from the predictability of pharmacological effects and utility, while confirming that pharmacological utility is capable of prediction.
- The Court affirmed factual conclusions from the trial judge that the inventors possessed and disclosed in the patent application both the factual data on which to base the prediction and a line of reasoning to enable them to make a sound prediction at the time they applied for the priority patent.
- Moreover, the Court affirmed the trial judge's conclusion that the in vitro tests to the human cell line would be adequate where the art would accept this as appropriately correlated to in vivo utility i.e., testing in humans.
- The Court rejected the suggestion that Glaxo/Wellcome was required to demonstrate utility through prior human clinical trials.
After-the-fact Validation
The Court confirmed that bare speculation, even if it afterwards turns out to be correct, will not amount to sound prediction. It rejected the suggestion, arising from earlier Canadian Federal Court of Appeal decisions, that mere speculation which later turned out to be true would be considered a sound prediction.
Inventorship
In reviewing inventorship, the Court characterized the ultimate question as: who is responsible for the inventive concept? The Court distinguished those who participate in the conception of the invention from those who participate in its verification. Notwithstanding the significant contribution made by the two individuals from the NIH, which served to support the utility through sound prediction, the Court concluded that they were not co-inventors.
This decision of the Supreme Court of Canada provides an extensive and valuable review of the doctrine of sound prediction. The decision is a reminder of the importance to be placed on the documentation of invention and testing activity.
John Bochnovic, Ottawa