There is a paucity of comprehensive analysis on the Canadian jurisprudence that has shaped the prohibition of methods of medical treatment from patentability. Contrary to the United States, methods of medical treatment have long been considered non-patentable subject matter in Canadian patent law. The prohibition, however, is not absolute: certain cosmetic and natural condition treatments , medical devices , diagnostic methods , and pharmaceutical claims  are patentable.
Despite extensive discussion by our courts, the reasons behind why such a prohibition exists remain unclear for both courts and patent lawyers. Similarly, the distinction between non-patentable methods of medical treatment and patentable claims before CIPO is sometimes unclear. The confusion is so great that the Federal Court of Appeal recently called for a full consideration of the prohibition by the Supreme Court of Canada in Bayer Inc v Cobalt Pharmaceuticals Co . Whereas some have asserted that the prohibition is variable and ever-changing , to the best of the authors’ knowledge, no scholarly publication currently exists that systematically reviews the entire breadth of Canadian case law concerning methods of medical treatment in the context of pharmaceutical patents up to and including 2018. After careful review of the relevant jurisprudence, it seems that while the rationale for the prohibition sits on shaky legal ground, there is a clear pattern in the way that the prohibition has been applied by the courts.
In light of the ongoing need for access to effective drugs for medical prescription in Canada, the patenting of new pharmaceutical innovation is of real use and benefit to all Canadians. Thus, this article focuses on the Canadian prohibition in the context of pharmaceutical claims in order to provide a clear understanding for patent agents and inventors alike of this confusing patent landscape, such that they may better prepare pharmaceutical patent claims that do not claim prohibited subject matter.
Have the courts ruled in an inconsistent fashion following the establishment of the prohibition on the patentability of methods of medical treatment?
To answer this question, the primary author performed a retrospective study on cases that concerned the prohibition following its establishment in the context of pharmaceutical patents on 19 November 1991 . The study’s objective was to determine whether any predictable pattern to the decisions could be found.
The study yielded 12 discrete cases that fit the temporal parameters . These were analyzed alongside their respective patents to look for a predictable pattern. They were also compared to the Canadian Intellectual Property Office’s (“CIPO”) revised examination practice respecting medical use claims as described by Patent Notice 2015-01 (“PN 2015-01”) which includes examples of purposive construction analysis of such claims for statutory subject-matter evaluation (“PN 2015-01 Examples”) . Although practice notices do not have the force of law, they do provide a guide as to whether or not a claim will be allowed by CIPO.
This study reveals that the courts have not ruled in an inconsistent fashion on the patentability of methods of medical treatment despite allegations to the contrary. From a detailed analysis of the case law while considering the invention as a whole against each impugned claim, it seems that the courts have followed a logical and predictable pattern in their decisions spanning from 19 November 1991 to 7 March 2018:
- When the invention is a new compound, a new use of a known compound or a new use of two known compounds, the claims will be patentable even if describing dosage ranges and/or ranges in dosage interval .
- When the invention is a new dosage regimen of a known drug for a known use, the claims will be patentable only if describing fixed dosage amounts and/or fixed dosage intervals and the skill or judgment of the medical practitioner would not be required to select the correct dosage .
- When the invention is a new dosage range of a known drug for a known use, the claims will not be patentable .
- When the invention is a new method of administration / new physical formulation of a known drug for a known use, the claims will be patentable whether they describe a dosage range or no dosage at all .
- When the invention is a new fixed dosage form of a known drug for a known use, the claim will be patentable if it recites a fixed dosage amount and the skill and judgment of the practitioner would not be required to determine the dosage .
Further, where applicable, the decisions matched the patentability criteria as described by PN 2015-01 and PN 2015-01 Examples. However, in spite of the apparently predictable pattern of patentability within case law decisions regarding the prohibition on pharmaceutical products, the results of this study are simplified. Accordingly, before any action is taken, legal advice on whether a pharmaceutical patent claim does, in fact, claim prohibited subject matter in Canada is recommended.
References Application for Patent Re Senentek plc, Re (1997), 77 CPR (3d) 321.  Visx Inc v Nidek Co (1999), 3 CPR (4th) 417.  CIPO Patent Notice PN 2015-02; CIPO Manual of Patent Office Practice (“MOPOP”), c 17.  Apotex Inc v Wellcome Foundation Ltd, 2002 SCC 77 (affirming  1 FC 495, affirming  FCJ No 382) [Apotex/Wellcome/AZT].  Bayer Inc v Cobalt Pharmaceuticals Co, 2015 FCA 116 (affirming 2013 FC 1061) [Bayer/Cobalt/drospirenone].  For example, Professor Norman Siebrasse in his IP blog, Sufficient Description <http://www.sufficientdescription.com/>.  Briefly, the prohibition was first introduced to Canadian courts by Lawson v Canada (Commissioner of Patents) (1970),  Ex CJ No 13, and expanded upon by Tennessee Eastman Co et al v Canada (Commissioner of Patents),  SCR 111 (affirming  Ex CJ No 14), shortly thereafter. The Supreme Court in Tennessee Eastman justified its endorsement of the prohibition on the basis of s.41(1) in the 1952 consolidation of the Patent Act, RSC 1952, c 203, which prohibited product claims for chemically-produced medical substances. Section 41(1) was later repealed on 19 November 1991 by Bill C-22, An Act to Amend the Patent Act and to Provide for Certain Matters in Relation Thereto, 2d Sess, 33rd Parl, 1986-1987, cl 14. From then on, pharmaceutical inventions could be directly patented as product claims. However, the prohibition on the patentability of medical methods continued in spite of the extinction of its statutory basis. As a result, this paper considers 19 November 1991 as the date that the prohibition was firmly established. This study’s parameters are thus temporally limited to relevant cases occurring after that date.  Merck & Co v Apotex Inc (CA),  2 FC 723 (affirming  FCJ No 1898) [Merck/Apotex/enalapril]; Apotex/Wellcome/AZT, supra note 4; Merck & Co v Apotex Inc, 2005 FC 755 [Merck/Apotex/alendronate]; Pfizer Canada Inc v Apotex Inc, 2005 FC 1421 [Pfizer/Apotex/azithromycin]; Axcan Pharma Inc v Pharmascience Inc, 2006 FC 527 [Axcan/Pharmascience/ursodiol]; Sanofi-Aventis Canada Inc v Hospira Healthcare Corp, 2009 FC 1077 [Sanofi-Aventis/Hospira/docetaxel]; Janssen Inc v Mylan Pharmaceuticals ULC, 2010 FC 1123 [Janssen/Mylan/galantamine]; Merck & Co v Pharmascience Inc, 2010 FC 510 [Merck/Pharmascience/finasteride]; Novartis Pharmaceuticals Canada Inc v Cobalt Pharmaceuticals, 2014 FCA 17 [Novartis/Cobalt/zoledronate]; AbbVie Biotechnology Ltd v Canada (Attorney General), 2014 FC 1251 [Abbvie/Canada/adalimumab]; Bayer/Cobalt/drospirenone, supra note 5; Hospira Healthcare Corp v Kennedy Trust for Rheumatology Research, 2018 FC 259 [Hospira/Kennedy/infliximab].  CIPO Patent Notice 2015-01 [PN 2015-01]; CIPO Examples of purposive construction analysis of medical use claims for statutory subject-matter evaluation, online: <https://www.ic.gc.ca/eic/site/cipointernet-internetopic.nsf/eng/wr03919.html> [PN 2015-01 Examples].  Merck/Apotex/enalapril, supra note 8; Apotex/Wellcome/AZT, supra note 4; Hospira/Kennedy/infliximab, supra note 8.  Merck/Apotex/alendronate, supra note 8; Janssen/Mylan/galantamine, supra note 8; Novartis/Cobalt/zoledronate, supra note 8; Abbvie/Canada/adalimumab, supra note 8; Bayer/Cobalt/drospirenone, supra note 5.  Axcan/Pharmascience/ursodiol, supra note 8.  Pfizer/Apotex/azithromycin, supra note 8; Sanofi-Aventis/Hospira/docetaxel, supra note 8.  Merck/Pharmascience/finasteride, supra note 8.
By Rochelle C Leung, Summer Law Student and Jennifer A. Marles, Partner