Canada: Federal Court Of Appeal Considers Standard For "Obvious To Try" Test


On December 15, 2015, the Federal Court of Appeal confirmed that the correct standard for determining whether an invention is obvious under the "obvious to try" test is still whether it was "more or less self-evident" to try to obtain the invention.  The Court rejected the application of a lower standard, such as whether the solution provides a "fair expectation of success" or whether "the skilled person had good reason to pursue predictable solutions": Eli Lilly Canada Inc v Mylan Pharmaceuticals ULC, 2015 FCA 286 at para 4.


For an invention to be patentable under Canadian patent law, the invention must not be obvious: section 28.3 of the Patent Act.  In Canada, an "obvious to try" test is used to determine whether an invention is obvious in fields where advances are often won by experimentation, such as the pharmaceutical industry.  The Supreme Court of Canada held in 2008 that "[f]or a finding that an invention was "obvious to try", there must be evidence to convince a judge on a balance of probabilities that it was more or less self-evident to try to obtain the invention. Mere possibility that something might turn up is not enough": Sanofi-Synthelabo Canada Inc v Apotex Inc, 2008 SCC 61 at para 66 [Sanofi].  The standard of "more or less self-evident" established in Sanofi is difficult to meet.

Like the Supreme Court of Canada in Sanofi, the Federal Court of Appeal in the 2009 decision of Pfizer Canada Inc v Apotex Inc, 2009 FCA 8 emphasized that the Canadian "obvious to try" test requires the invention to be "more or less self-evident".

The "more or less self-evident" standard originally came from the UK Court of Appeal decision Saint-Gobain PAM SA v Fusion Provida Ltd, [2005] EWCA Civ 177.  However, the House of Lords subsequently reframed the standard in the UK as "a fair expectation of success": Conor Medsystems Inc v Angiotech Pharmaceuticals Inc, [2008] UKHL 49.  The expectation of success required to meet this standard differs depending on the particular facts of the case.  The UK Court of Appeal has acknowledged that the "more or less self-evident" standard may still be appropriate in some cases.  However, it has specifically rejected a submission that a court can only make a finding of obviousness where "it is manifest that a test ought to work", because that would "impose a straightjacket upon the assessment of obviousness": Generics (UK) LTD (t/a Mylan) v Novartis AG, [2012] EWCA Civ 1623.  Therefore, these decisions suggest that the UK standard is more flexible than the standard in Canada. 

Canadian decisions have occasionally used language drawn from these later UK decisions when discussing obviousness, which may have led to some uncertainty as to whether the Canadian test continued to require the application of the more stringent "more or less self-evident" standard.

Decision under appeal

In Eli Lilly Canada Inc v Mylan Pharmaceuticals ULC, 2015 FC 178, the Federal Court dismissed an application by Eli Lilly Canada Inc. and ICOS Corporation for an order prohibiting the Minister of Health from issuing a notice of compliance for Mylan's tadalafil tablets based on comparison to Eli Lilly's CIALIS. 

Mylan had alleged that it would not infringe Canadian Patent No. 2,379,948 ('948), and that the patent was invalid for obviousness.  The Federal Court held that both of these allegations were justified. 

With respect to obviousness, the Federal Court found that the inventive concept of the '948 patent was that the dissolution and stability of tadalafil could be improved by reducing its particle size and formulating it with specific excipients.   

The Federal Court held at para 150 that the "obvious to try" test is "whether the skilled person had good reason to pursue predictable solutions or solutions that provide a "fair expectation of success"".

Applying this test, the Federal Court held that the skilled person would have had a fair expectation of success in trying the formulation disclosed in the '948 patent.  The excipients disclosed in the patent were standard excipients for pharmaceuticals, and it was well-known that particle size reduction could improve the dissolution and bioavailability of drugs. 

However, the Federal Court also held that the formulation was "obvious to try" even if the standard was whether it was "more or less self-evident" to try to obtain the invention.


On appeal, Eli Lilly Canada Inc. and ICOS Corporation alleged that the Federal Court judge had erred in law by applying an incorrect test for obviousness.

In dismissing the appeal, the Federal Court of Appeal agreed that the Federal Court should have applied the test from Sanofi, and not a test based on a "fair expectation of success" or whether "the skilled person had good reason to pursue predictable solutions".  However, as the Federal Court judge had also found the alleged invention "obvious to try" based on the standard from Sanofi, the Federal Court of Appeal held that the error was immaterial to the judge's decision.


Following this decision by the Federal Court of Appeal, there should be more certainty in the application of the "obvious to try" test in the Federal Court, with the Federal Court of Appeal having confirmed that the correct test is whether or not it was "more or less self-evident" to try to obtain the invention as established in Sanofi, and not a lower standard.

For further information please contact a member of our firm's Litigation group.

The preceding is intended as a timely update on Canadian intellectual property and technology law. The content is informational only and does not constitute legal or professional advice. To obtain such advice, please communicate with our offices directly.

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