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FCA Confirms Obviousness of Lilly’s Tadalafil Patent

In Eli Lilly Canada Inc. v. Mylan Pharmaceuticals ULC, 2020 FC 816, Justice St-Louis held that the asserted claims of Lilly’s Patent No. 2,371,684, relating to use of oral pharmaceutical dosage forms containing tadalafil for the treatment of erectile dysfunction, were anticipated and obvious (see our previous post here). 

In conducting the obviousness inquiry, Justice St-Louis held that she did not need to look beyond the essential elements of the claims to understand the inventive concept of the 684 Patent. Justice St-Louis identified the inventive concept as “the claimed dosages of tadalafil, orally administered, provide efficacy to treat male ED”. Justice St-Louis held that the inventive concept did not include certain advantages raised by Lilly, including minimization or elimination of flushing as compared to higher doses of tadalafil. Justice St-Louis found that the gap between the prior art and the inventive concept of the 684 Patent was the lower and narrower subset of dose ranges in the 684 Patent and concluded that the gap would have been obvious to the skilled person. 

Lilly appealed this decision on the basis that Justice St-Louis erred in the way in which she identified and construed the inventive concept within the obviousness framework, in finding that the asserted claims of the 684 Patent were anticipated, and in finding that the 684 Patent was not a selection patent. Justice Rivoalen, for the Court of Appeal, focused her attention on the obviousness issue.

Lilly took the position that Justice St-Louis failed to perform the obviousness analysis in light of the correct inventive concept, arguing that she incorrectly held:

  1. the inventive concept of the Asserted Claims of the 684 Patent is synonymous with the essential elements of the claims; and
  2. any advantages described in the 684 Patent are not part of the inventive concept.

Lilly argued that the inventive concept of the asserted claims went beyond the essential elements of those claims and required the trial judge to review the disclosure of the 684 Patent to fully understand the solution taught by the patent and the motivation to pursue it. On appeal, Lilly’s proposed inventive concept was “a minimization or elimination of flushing as compared to larger doses of tadalafil”.

Justice Rivoalen held that even if she were to accept Lilly’s vision of the inventive concept, Justice St-Louis’ finding that the invention was obvious must stand based on her uncontested factual findings. With Lilly’s proposed inventive concept in mind, the gap between the prior art and the inventive concept was “the lower and narrower subset of dose ranges in the 684 Patent and the improved side effects profile of minimization or elimination of flushing.” However, as acknowledged by Justice St-Louis, in identifying a dose range, the routine steps taken by the skilled person would include identifying side effects (such as flushing) and the safety profile of the dose range. Having already identified a viable compound for the treatment of ED, the skilled person “would certainly be motivated to identify the doses that offer the best balance between efficacy, and safety and tolerability to push the compound one-step closer to the market”.

Justice Rivoalen found that it was not necessary to address Lilly’s arguments regarding anticipation and whether the 684 Patent is a selection patent in light of her conclusion on obviousness.

Lilly’s appeals were dismissed.

Aitken Klee LLP represented three of the five respondents in this appeal. Scott Beeser represented Teva. Marcus Klee and Aleem Abdulla represented Pharmascience and Riva.

A copy of the decision can be found here.

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