Promise Of The Patent Post-Plavix: Three Steps Forward, One Step Back

An internationally recognized requirement for patentability is that an invention must be "useful." Typically, the threshold of utility is easily met for inventions that have commercial applicability, such as a drug candidate. Developments in Canadian patent jurisprudence over the last decade; however, have raised the utility requirement for some patents under the so-called "promise of the patent" doctrine. According to this doctrine, if a patent sets out an explicit promise of utility, the patent will be void if it does not meet this promised utility. The Federal Court of Appeal (FCA) in Eli Lilly Canada v Novopharm, 2010 FCA 197 describes the heightened utility requirement:

Where the specification does not promise a specific result, no particular level of utility is required; a "mere scintilla" of utility will suffice. However, where the specification sets out an explicit "promise", utility will be measured against that promise. The question is whether the invention does what the patent promises it will do. (at 76) [citations omitted].

The promise doctrine has drawn considerable attention, particularly in the context of pharmaceutical patents, where it has served as a basis for the invalidation of a number of patents and given rise to a high profile pharmaceutical company NAFTA challenge against Canada.1 Critics of the promise doctrine charge that the doctrine unfairly puts at risk many useful patents, because any stray phrase professing a benefit of the invention could be construed as a promise by the courts.

Recently, the FCA in a case involving the drug clopidogrel bisulfate (marketed as PLAVIX®) (Sanofi -Aventis v Apotex, 2013 FCA 186 ('PLAVIX')) articulated a more restrained approach to the promise doctrine.

The FCA held that it is improper to assume that all patents make a promise of utility and emphasized that a promise should only be construed when "the inventor makes an explicit promise of a specific result" (at 49) [emphasis added]. Otherwise, a "mere scintilla" of utility is sufficient. A review of post-PLAVIX jurisprudence from the Federal Court confi rms a shift towards the restrained approach advocated by the FCA in PLAVIX, with one notable exception.2

Post-PLAVIX Federal Court Decisions

The first post-PLAVIX decision by the Federal Court to address the promise doctrine was Pfizer v Mylan, 2014 FC 38 ("Mylan"), involving Canadian Patent No. 2,177,576 ('576) covering the drug celecoxib (marketed as CELEBREX®). Interestingly...