Summary – The Federal Court of Appeal (FCA) dismissed an appeal from a decision of the Federal Court (FC) under the Patented Medicines (Notice of Compliance) Regulations, prohibiting the Minister of Health from issuing a Notice of Compliance to Mylan to sell its generic version of AstraZeneca’s ARIMIDEX® (anastrozole) until after the expiry of Canadian Patent No. 1,337,420 (`420 Patent). The FCA agreed with the FC’s construction of the object clause in the `420 Patent as merely a goal or purpose of the invention rather than a promise of its utility.
Analysis – The `420 Patent relates to (substituted-aralkyl) – heterocyclic compounds, including anastrozole, and in particular, to such compounds which are useful as inhibitors of the enzyme aromatase. Aromatase inhibitors block the conversion of androgens to estrogens, which has particular significance for the treatment of certain forms of breast cancer. The claims of the `420 Patent cover, inter alia, anastrozole per se, compositions comprising anastrozole and the use of anastrozole as an inhibitor of the enzyme aromatase.
This appeal turned principally on the promise of the `420 Patent and the construction of a single “object clause” in its description, which reads: “It is a particular object of the present invention to provide aromatase inhibitory compounds with fewer undesirable side effects than aminoglutethimide”. The FCA agreed with the FC that “an examination of the patent as a whole supports the conclusion that, unlike the express claims of the patent, the object clause contains no more than a forward looking aim of the invention” rather than a promise that anastrozole had achieved this aim by the filing date of the patent. The FCA repeatedly referred to the fact that side effects were not mentioned anywhere else in the patent [para. 33].
In addition, the FCA determined that the FC did not place undue weight on the dictionary definition of the term “object”, that it was reasonable for the FC to base its conclusions on expert testimony that the object clause set out a long-term aim and not a promise, and that there was no internal incoherence in the FC’s reasons (the FCA found that even if the FC “appears to infer the meaning of the patent from the absence of clinical trials”, this played a minor role in the its reasoning [para. 46]).
Practice Point – A patent description must contain: the technical field of the invention, the nature of the technical problem being addressed, and the solution to that problem. Although the terms “problem” and “solution” need not appear in the description, Patentees will often describe their invention in terms of its “objects”. This decision may have Patentees breathing a sigh of relief by specifying that such an “object clause” in a patent is not necessarily elevated to a promise of utility.
It is of note however that, since the FCA found there was no promised utility with respect to improved side effects, it declined to answer the “interesting question” whether such utility had been demonstrated as of filing given the patent did not refer to any study directed thereto (AstraZeneca had only “secretly” shown selectivity [paras. 19, 30]). It is expected that the Supreme Court of Canada will clarify this question when it releases its much anticipated decision regarding VIAGRA® (sildenafil) (on appeal from Novopharm Ltd. v Pfizer Canada Inc., 2010 FCA 242).