New CIPO Practice Notice On Patentable Subject-Matter

In March 2026, the Canadian Intellectual Property Office published a practice notice titled “March 2026 Practice Notice on Patentable Subject-Matter under the Patent Act” (the Notice), providing updated guidance on the Patent Office’s interpretation of patentable subject‑matter.

The Notice reflects recent guidance from Canadian courts in Canada (Attorney General) v Benjamin Moore & Co., 2023 FCA 168, Dusome v Canada (Attorney General), 2025 FC 1809, and Pharmascience Inc. v Janssen Inc., 2024 FCA 23, and supersedes guidance currently present in the Manual of Patent Office Practice related to the “contribution” of a claim to a “technological solution to a technological problem”, and evaluating essentiality of elements based on a “problem and solution” during purposive construction, among other things.

The Notice emphasizes that the analysis of patentable subject‑matter begins with purposive construction. Once claims are properly construed, the subject‑matter can then be assessed for compliance with the requirements of the Patent Act. The Notice discusses how this analysis applies in three specific contexts: computer‑implemented inventions, medical diagnostic methods, and medical uses.

With respect to computer-implemented inventions, the Notice confirms that merely having a computer as an essential element of the claims does not mean that the requisite physicality for patentable subject-matter is satisfied. The requisite physicality may be present where additional physical essential elements such as a measurement step or sensor are present, or where the computer-implemented invention improves the functioning of the computer. In computer-implemented inventions where there is no physicality outside of the computer itself, the Notice proposes asking “the Schlumberger question.” The Notice provides that if a computer merely processes an abstract algorithm or set of rules in a well-known manner and such processing does not improve the functioning of the computer, then the computer is not part of “what, according to the application, has been discovered”. In contrast, if processing the algorithm improves the functioning of the computer then what has been discovered includes the use of a computer as more than a bare practical application, and that use constitutes part of the patentable subject-matter.

For medical diagnostic methods, the Notice notes that such claims often include a correlation element, which on its own, is not considered to be patentable subject-matter. However, a medical diagnostic method claim may constitute patentable subject‑matter if it includes the requisite physicality, such as defined physical steps like measuring, identifying, detecting, or assaying.

Finally, the Notice addresses medical use claims, stating that claims falling under the method of medical treatment exclusion are not patentable subject-matter. It notes, however, that what constitutes a method of medical treatment is currently being considered by the Supreme Court of Canada.

The Notice concludes by providing a link to examples applying the patentable subject-matter analysis.

Summary By: Claire Bettio