Updated Guidance From CIPO On Patentable Subject-Matter

On 24 March 2026, the Canadian Intellectual Property Office (CIPO) issued an updated Practice Notice on Patentable Subject-Matter under the Patent Act¹ (the “2026 Subject-Matter PN”). The 2026 Subject-Matter PN supersedes a long-standing CIPO practice notice from 2020² (the “2020 Subject-Matter PN”) on the same topic.

New Test for Patentable Subject Matter

The 2026 Subject-Matter PN outlines the new test for patentable subject-matter that will be applied by CIPO when reviewing the claims of a patent application for compliance with the Patent Act. Implicit in the test are two steps:

1. Step 1: Purposive Construction: Purposively construe the scope of the claims and determine which features of the claims are essential and non-essential.
2. Step 2: Physicality Requirement: Determine if the features of the claims meet the physicality requirement and are therefore patentable subject-matter.

Step 1 involves considering the whole of the specification “to ascertain the nature of the invention“. Considerations include the way claim elements are presented in the specification, what was invented, and what was claimed to have been invented.

Step 2 follows purposive construction of the claims to determine if the claims are directed to patentable subject-matter. If the claimed subject-matter includes a disembodied idea, a scientific principle or an abstract theorem, the claimed subject-matter is patentable if such subject matter is part of a practical application that has physical existence or manifests a discernible effect or change. Discernible is interpreted as referring to physical effects or changes.

The 2026 Subject-Matter PN includes specific guidance on the two technical fields where patentability of subject-matter is most commonly at issue: computer-implemented inventions, and methods of medical diagnosis and treatment.

Application to Computer-Implemented Inventions

The 2026 Subject-Matter PN concedes that a computer will be an essential element of most computer-implemented invention claims. However, the mere fact that a computer is an essential element of the claims does not necessarily mean the claims meet the physicality requirement. Additional essential physical elements may be needed to meet the physicality requirement, for example a measurement step or sensor, or output means such as a robotic actuator.

If there is no physicality outside of the computer system elements, then the claimed subject matter must answer “the Schlumberger question” to be patentable subject-matter. The Schlumberger question, as specified by the 2026 Subject-Matter PN, is whether a claimed abstract algorithm or abstract set of rules is either:

1. processed by the computer in a well-known manner and does not improve the functioning of the computer; or
2. provides “something more”, such as an improvement to the functioning of the computer.

Where the claimed subject matter provides “something more”, then the “something more” imparts physicality to the claim, and the claim therefore recites patentable subject-matter.

Application to Medical Diagnostic Methods

In the context of a medical diagnostic method, an element correlating a specific analyte or the result of a medical test to a disease is generally considered a patent ineligible abstract idea or disembodied idea. A purposively constructed claim to a medical diagnostic method requires a practical application to meet the physicality requirement. For example, physical steps such as measuring, identifying, detecting, or assaying the presence or quantity of an analyte in a sample may provide the requisite practical application to be patent eligible.

Application to Medical Uses

Per the 2026 Subject-Matter PN, methods of medical treatment or surgery are not patent eligible.³ Methods of medical treatment include those which the use of require the exercise of skill and judgment, or where an active medical treatment or surgical step is an essential element of the claim. Notably, per the current prevailing case law in Canada, the presence of a fixed or variable dosage regimen is not alone determinative of patentability of a claim.

Conclusion

The 2026 Subject-Matter PN is a substantial change from the previous position of CIPO expressed in the 2020 Subject-Matter PN. Most notably, the 2026 Subject-Matter PN substantially deviates from the determination of an “actual invention” which was key to subject-matter eligibility in the 2020 Subject-Matter PN. The determination of the “actual invention” under the 2020 Subject-Matter PN was seen by many patent practitioners as ambiguous and unfounded in patent jurisprudence. In this regard, the 2026 Subject-Matter PN is a welcome departure from CIPO’s previous interpretation of the law on patent-eligibility, and appears to be a positive development for patentees. However, whether the 2026 Subject-Matter PN will result in more certainty in how CIPO will assess subject-matter eligibility, and whether or not that increased certainty will benefit applicants, remains to be seen.

Footnotes

1. March 2026 Practice Notice on Patentable Subject-Matter under the Patent Act.

2. Patentable Subject-Matter under the Patent Act.

3. Note, the Supreme Court of Canada is currently considering the patentability of methods of medical treatment (see Pharmascience Inc. v. Janssen Inc., et al., Supreme Court file number 41209).

The foregoing provides only an overview and does not constitute legal advice. Readers are cautioned against making any decisions based on this material alone. Rather, specific legal advice should be obtained.

© McMillan LLP 2025