The “obvious to try” test in Canada is different from the “worth a try” test applied in a parallel U.K. proceeding, according to a recent decision of the Federal Court of Appeal pertaining to Pfizer’s Canadian patent for VIAGRA.
Apotex Inc. v. Pfizer Canada Inc., 2009 FCA 8 (“Apotex”), involved an appeal from a lower Court decision that had upheld the validity of Pfizer’s Canadian Patent No. 2,163,446, which disclosed and claimed the use of sildenafil or its salts for the treatment of erectile dysfunction (“ED”). The cited prior art included scientific journal articles containing speculative suggestions that PDE inhibitors could be developed to treat ED, as well as a prior patent disclosing sildenafil as a PDE inhibitor for the treatment of cardiovascular disorders. At first instance, the Court had concluded that the most that could have been said at the priority date was that the claimed invention was “worth a try”, which was insufficient to render it obvious. In reaching this finding, the Court had applied the test for obviousness set forth in Beloit Canada Ltd. v. Valmet OY (1986), 8 C.P.R. (3d) 289 (F.C.A.) (“Beloit”), according to which a claimed invention is obvious only if the state of the art and common general knowledge would have led an unimaginative skilled technician directly and without difficulty to the claimed invention.
The Beloit judgment was the leading authority on obviousness in Canada for more than two decades prior to November 2008. Both before and after Beloit, Canadian courts had consistently rejected the U.K. “worth a try” test for obviousness in Canada.
On appeal, however, the appellant argued that the law of obviousness had changed in this respect as a result of the November 6, 2008, judgment of the Supreme Court of Canada in Apotex Inc. v. Sanofi-Synthelabo Canada Inc., 2008 SCC 61 (“Sanofi”). In Sanofi, the Supreme Court declined to apply the Beloit test and instead applied a more general factual framework, focusing on whether the differences between the claimed invention and the state of the art would have been obvious.
Moreover, the Supreme Court held in Sanofi that an “obvious to try” inquiry may be appropriate in “areas of endeavour where advances are often won by experimentation” and identified a number of non-exhaustive considerations to aid in the “obvious to try” inquiry:
- Is it more or less self-evident that what is being tried ought to work? Are there a finite number of identified predictable solutions known to persons skilled in the art?
- What are the extent, nature and amount of effort required to achieve the invention? Are routine trials carried out or is the experimentation prolonged and arduous, such that the trials would not be considered routine?
- Is there a motive provided in the prior art to find the solution the patent addresses?
- Another important factor may arise from considering the actual course of conduct that culminated in the creation of the invention.
With respect to the first of these considerations, the Supreme Court emphasized that “the ‘obvious to try’ test will work only where it is very plain or … self-evident that what is being tested ought to work.”
Apotex argued that the Sanofi decision fundamentally changed the law of obviousness in Canada by incorporating the U.K. “worth a try” test and that the Federal Court Judge had erred in failing to apply this test. Apotex also argued that the U.K. Court of Appeal decision in Lilly Icos Ltd. v. Pfizer Ltd., [2002] EWCA Civ 1 (“Lilly Icos”), which invalidated Pfizer’s U.K. VIAGRA patent for obviousness, should be used as a blueprint for the application of the “worth a try” test in Canada.
In rejecting these submissions, the Federal Court of Appeal observed that “obvious to try” as explained by the Supreme Court in Sanofi is not synonymous with “worth a try”:
“The test recognized is ‘obvious to try’ where the word ‘obvious’ means ‘very plain.’ According to this test, an invention is not made obvious [merely] because the prior art would have alerted the person skilled in the art to the possibility that something might be worth trying. The invention must be more or less self-evident.”
The Federal Court of Appeal rejected the contrary decision of the U.K. Court of Appeal in Lilly Icos on the ground that it had been reached on the basis of a broader test for obviousness than that adopted by the Supreme Court in Sanofi. The Court commented that the test applied by the U.K. Court of Appeal appears to be met if the prior art indicates that something may work and there is sufficient motivation to make this avenue worthwhile to pursue, even if the claimed invention was not “more or less self-evident.” The Court characterized this approach as being based on the mere possibility that something may work and held that this approach had been rejected by the Supreme Court in Sanofi. The Court held that the Canadian “obvious to try” test requires that it must be “self-evident” that something will work, rather than just possible that something may work.
The Federal Court of Appeal noted the U.K. court’s apparent view in Lilly Icos that where the motivation to achieve a result is very high, the degree of expected success becomes a minor matter. While the Court agreed that a high degree of motivation may compel the skilled person to pursue experimentation even if the chances of success are not particularly high, the Court emphasized that:
“[T]he degree of motivation cannot transform a possible solution into an obvious one. Motivation is relevant in determining whether the skilled person has good reason to pursue ‘predictable’ solutions or solutions that provide ‘a fair expectation of success’ …”
In other words, no degree of motivation will satisfy the separate requirement that it must be “more or less self-evident that what is being tried ought to work.” The Court of Appeal appears to have compared this requirement with a “fair expectation of success” or a “predictable solution,” citing recent judgments of the House of Lords (in Angiotech Pharmaceuticals Inc. v. Conor Medsystems Inc., [2008] UKHL 49 (“Angiotech”) at para. 42) and the United States Supreme Court (in KSR International Co. v. Teleflex Inc., 127 S.Ct. 1727 (2007) at 1742). Interestingly, in Angiotech, the House of Lords reversed a finding of obviousness that had been based on the “obvious to try” test on the ground that a fair expectation of success had not been established; thus, it is possible that U.K. law may be moving away from the approach taken in Lilly Icos and closer to the Canadian position. However, it is clear from Angiotech that the degree of the expectation of success required to constitute a “fair” expectation in the U.K. is a question of fact that depends in part upon the degree of motivation, whereas the expectation of success and the degree of motivation are independent considerations under Canadian law.
From the Apotex and Sanofi decisions, it appears that the introduction of an “obvious to try” inquiry into Canadian law has not significantly raised the threshold degree of inventiveness or non-obviousness required to support a patent. It is clear from these decisions that a claimed invention will not be held obvious merely because it was worth a try, unless it would have been self-evident that what was being tested ought to work. These decisions leave open the question as to when an “obvious to try” inquiry is or is not appropriate. This inquiry has thus far been applied only to the pharmaceutical industry, but the reference in Sanofi to “areas of endeavour where advances are often won by experimentation” is literally broad enough to encompass many other industries. The full impact of Sanofi remains to be seen in future cases.
Kathy Rzeszutek and Stephen J. Ferance, Vancouver
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