On February 2, 2015 Justice de Montigny of the Federal Court released his judgment and reasons in Eli Lilly Canada Inc. v. Mylan Pharmaceuticals ULC, 2015 FC 125, dismissing Lilly’s application for an order prohibiting the Minister of Health from issuing a Notice of Compliance to Mylan until the expiry of Canadian Patent No. 2,371,684 (the “‘684 Patent”). The ‘684 Patent claims a dosage form of tadalafil and its use to treat erectile dysfunction (“ED”). This decision is the second in a series of three prohibition applications by Lilly relating to its tadalafil patents.

The use of tadalafil for the treatment of ED was claimed in the earlier ‘784 Patent which was the subject of a prohibition application summarized in a January 26, 2015 post on snIP/ITs. In contrast to that decision, Justice de Montigny took a harder stance on the promised utility of the ‘684 Patent. He noted that the patent made several explicit statements promising particular results, and that this promised utility was neither disclosed nor soundly predicted on the filing date. Justice de Montigny ultimately found that Mylan’s allegations of invalidity on the basis of lack of utility, anticipation and obviousness were justified.


Lilly submitted that the ‘684 Patent promises that the claimed dosage forms will be effective in the treatment of ED and will have a better side effect profile than sildenafil, an earlier ED drug. Mylan argued that the ‘684 Patent goes far beyond Lilly’s construction and promises that the claimed doses will minimize three specific side effects to insignificant levels.

Justice de Montigny preferred Mylan’s construction, noting that the ambitious and explicit statements throughout the patent promise much more than a marginal improvement over sildenafil. He observed that reading down the promise in accordance with Lilly’s construction would “fly in the face of the clear language of the ‘648 Patent”.

Justice de Montigny further held that, as of the filing date, this promised utility had not been demonstrated. He noted that the only study comparing the occurrence of one of the side effects showed no difference between the compounds. He also rejected Lilly’s assertion that the promised utility could be predicted, noting that the patent’s disclosure of a study comparing the two compounds was “very sketchy” because it failed to refer to or explain the results of the head-to-head testing in the study:

“This failure is clearly unacceptable in a Patent that promises not only efficacy in treating ED, but also a better side effect profile […] and a patentee should not be able to benefit from a partial, if not misleading, disclosure.”

Anticipation & Obviousness

Justice de Montigny held that the ‘684 Patent is not a selection patent because the special advantage is not peculiar to the particular dosage range claimed. On this basis, he held that the ‘684 Patent is anticipated by the ‘784 Patent because the claimed invention was disclosed and enabled by the ‘784 Patent. He explained that:

“When a second patent is not interpreted as a selection patent, its advantages do not factor into the inquiry of anticipation and need not be disclosed in a previous patent to be anticipated.”

Justice de Montigny also held that it was obvious that the lower and narrower doses claimed in the ‘684 Patent would be effective in treating ED and would lead to fewer side effects. He noted that knowledge about the efficacy and side effects of an earlier, similar ED drug would have guided the inventors’ choice of dose, and that lowering dosage is a standard way to reduce side effects.