Court Rejects Attempt To "Stretch" Patent Claim Language

• Published date: 14 January 2021
• Subject Matter: Intellectual Property, Patent
• Law Firm: Bereskin & Parr LLP
• Author: Mr Andrew McIntosh and Martin Brandsma

Patent claims are frequently analogized to "fences" and "boundaries", which delineate the extent of the patent's monopoly. Placement of those boundaries is critical to a patent's enforceability, and ultimately its value. As noted by Canada's Supreme Court, "...if, in order to guard against possible invalidity, some area is left open between what is the invention as disclosed and what is covered by the claims, the patent may be just as worthless as if it was invalid".¹ A recent decision issued by the Chief Justice of the Federal Court of Canada in Allergan Inc. v. Sandoz Canada Inc., 2020 FC 1189 ("Rapaflo") illustrates this challenge.

In Rapaflo, Allergan, Inc. ("Allergan") brought an action against Sandoz Canada Inc. ("Sandoz") under Canada's Patented Medicines (Notice of Compliance) Regulations (the "Regulations"). Allergan sought a declaration that Sandoz's generic silodosin product would infringe Canadian Patent No. 2,507,002 (the "002 Patent"). Silodosin is used to treat benign prostatic hyperplasia.

Among other things, the 002 Patent claims a capsule formulation comprising "a granule prepared by wet granulation of a mixture of" silodosin and certain identified excipients. Central to the case was whether "granule" and "prepared by wet granulation" (collectively, the "Wet Granulation Elements")'both explicitly claimed'are essential elements. It was undisputed that Sandoz's generic product does not contain granules and is not manufactured with the wet granulation process.

Allergan submitted the Wet Granulation Elements were non-essential, and consequently the Sandoz product would infringe the 002 Patent. The Court disagreed, finding the Wet Granulation Elements essential and noting that "Allergan's suggestion...is based on a reading of the patent that, if upheld, would undermine the certainty and predictability of the patent system, and chill competition" (Rapaflo at 2).

Essential vs. Non-Essential Claim Elements

The Court stated that the assessment of whether a claim element is essential begins with the presumption that all elements are essential, and that where a party alleges otherwise, it bears the onus of establishing "non-essentiality". That onus can be met by demonstrating either:

1. "that on a purposive construction of the words of the claim it was clearly not intended that a particular element be essential"; or
2. "that at the date of publication of the patent, the skilled person would have appreciated that the element in question could be...