In Sanofi-Aventis Canada Inc. v. Ratiopharm Inc. (2010 FC 230), the Federal Court (“FC”) denied Sanofi-Aventis Canada’s (Sanofi) application to prohibit the Minister of Health from issuing a Notice of Compliance (“NOC”) to Ratiopharm Inc. pursuant to section 6 of the Patented Medicines (Notice of Compliance) Regulations (“PMNOC Regulations“). The FC held Sanofi’s Canadian Patent No. 2,177,772 was invalid for overbreadth, lack of utility and in any case was not infringed by the use of Ratiopharm’s proposed composition.

Ratiopharm’s NOC application was for irbesartan, a drug for treatment of cardiovascular ailments such as hypertension and heart failure. Canadian Patents 2,177,772 (“’772 patent”) and 2,057,913 had been listed by Sanofi on the patent register in respect of irbesartan pursuant to section 4 of the PMNOC Regulations. Ratiopharm accepted that no NOC would issue prior to expiry of the ’913 patent, so only the ’772 patent remained for consideration. The ’772 patent claims pharmaceutical compositions containing irbesartan, preferably in the form of tablets with a high relative amount of the active ingredient that allowed for a rapid dissolution and release.

Claims construction

Claim 1 of the ’772 patent clamed a pharmaceutical composition of irbesartan with a specified dissolution performance “such that about 80% or greater of the irbesartan or salt thereof contained in said tablet dissolves within 30 minutes.” The parties disagreed on the meaning of the term “about”. The FC found that in the absence of other indications, “about” meant, in accordance with expert evidence, “within 10%”. The main issue, however, was whether the dissolution performance of 80% or greater was a promise of performance or whether it was a limitation on the claim. The FC held that while this determination would not effect the outcome of the validity analysis the stated dissolution performance was a promise that a composition in accordance with the claim would give a dissolution performance of 80% or greater. This was consistent with Sanofi’s evidence that it was in fact this rapid dissolution and immediate release that was the “essence of the patent”.

Obviousness

The FC examined the Supreme Court of Canada’s ruling in Apotex Inc. v. Sanofi-Synthelabo Canada Inc. (2008 SCC 61) and the “obvious to try” inquiry which supplements the overall obviousness inquiry by examining:

1. 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?
2. What is the extent, nature and amount of effort required to achieve the invention? Routine trials or prolonged and arduous experimentation?
3. Is there a motive provided in the prior art to find the solution the patent addresses?

The FC accepted expert evidence that “there was extensive testing in order to come to the formulation in the ’772 Patent.” Combined with the fact that “Sanofi-Aventis never achieved 70% active ingredients in any of their tests” the FC concluded the ’772 patent “requires trial and error to achieve the 85% dissolution rate.” This was in light of that fact that while there is no maximum range of excipient/filler material in formulation patents “The jurisprudence accepts a range so long as what constitutes an ‘effective’ amount is clear and certain.”

The FC found “the situation is analogous to a recipe which promises a result. . . . Aventis has not been able to fulfil the promise.” The FC reasoned “A central difficulty of the promise is that it is not obvious to a skilled person which element and in which proportions will yield the promised result. The experts on all sides agree that a great deal of testing would be required in order to come to the correct formulation. This confirms the overbreadth of the patent to achieve the promise.”

The FC concluded the patent would also fail on utility grounds because it has not been demonstrated that all combinations claimed would generated an 80% dissolution performance. The FC noted that “a patent claim must not exceed either the invention made or the invention disclosed”. In fact, Sanofi was never able to produce a formulation that achieved 50% active ingredient, while the claim called for “about 20 to about 70% Irbesartan”.

In respect of infringement, the issue was whether Ratiopharm’s excipient, which is a multipurpose ingredient, performed the function of the diluent filler material to support the infringement allegations. The FC concluded that only the main purpose of the ingredient had to be considered, not whether it could have other functions. Thus, even if Ratiopharm’s excipient could be used as a filler, the FC found that it was primarily used in Ratiopharm’s formulation as a binder agent and the ’772 patent would not be infringed by its presence.