Canadian Patent Law Of Obviousness: R.I.P. Fair Expectation Of Success

The question of whether a "fair expectation of success" is the correct legal standard applicable to an obvious to try analysis was finally laid to rest in the Federal Court of Appeal's recent important decision of Eli Lilly v Mylan (2015 FCA 286). A unanimous panel held that a "fair expectation of success" was not the correct standard. Instead, the higher "more or less self-evident" test articulated by the Supreme Court of Canada in Sanofi-Synthelabo (2008 SCC 61) was reaffirmed as the correct legal standard. The higher standard for obviousness makes it more difficult to invalidate a patent, thereby strengthening protection for patent-holders.

The Eli Lilly case was a NOC case. Lilly sought to prevent Mylan from obtaining marketing authorization for generic CIALIS®. The asserted '948 patent was directed to a pharmaceutical formulation of reduced particle size of the active (tadalifil) with particular excipients for ED treatment.

At first instance, the applications judge found the allegation of obviousness justified. With respect to the obvious to try analysis, the court recognized two different legal standards: (i) the so-called "fair expectation of success" standard; and (ii) the "more or less self-evident" standard articulated by the Supreme Court in Sanofi-Synthelabo.

The applications judge held in 2015 FC 178 the correct legal standard was a "fair expectation of success" and applied it, finding the invention obvious to try:

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