CIPO's approach to patentable subject matter has been unsettled since the Federal Court of Appeal struck down the Federal Court's imposed test in Canada (Attorney General) v. Benjamin Moore & Co., 2023 FCA 168, and left the analytical framework genuinely open rather than replacing it with a new bright-line rule. The March 2026 practice notice is CIPO's attempt to fill that gap with settled guidance of its own, informed by the case law that has developed since.
What the Old Guidance Required
Under CIPO's 2020 guidance, an examiner assessing patentable subject matter identified the "actual invention" as a distinct step, often by asking whether the claimed contribution amounted to a technological solution to a technological problem, and treated a claim's essential elements as shaped by that problem-and-solution inquiry. Practitioners had long viewed this approach as difficult to reconcile with settled Canadian patent jurisprudence on purposive construction, and the courts, in Benjamin Moore, Pharmascience Inc. v. Janssen Inc., 2024 FCA 23, and Dusome v. Canada (Attorney General), 2025 FC 1809, gradually confirmed those concerns.
What the New Notice Changes
The March 2026 notice supersedes the Manual of Patent Office Practice guidance tied to a claim's "contribution," to a technological solution to a technological problem, and to assessing essentiality of elements through a problem-and-solution lens. The separate "actual invention" inquiry that previously followed purposive construction is removed entirely; the nature of the invention is now assessed as part of purposive construction itself, using a two-step framework of purposive construction followed by a physicality assessment, rather than a distinct third step layered on top.
Why This Is a Welcome Development for Patentees
Practitioners had widely viewed the "actual invention" step under the 2020 guidance as ambiguous and poorly grounded in Canadian patent jurisprudence, since it gave examiners a separate lever to narrow a claim's scope beyond ordinary purposive construction. Folding that inquiry back into purposive construction, consistent with how Canadian courts have approached claim construction outside the patentable subject matter context, is a more predictable and legally consistent framework, and one better aligned with the case law CIPO itself now cites as its authority.
Who Is Most Affected
The notice speaks directly to computer-implemented inventions, medical diagnostic methods, and medical use claims, three categories where the "actual invention" and problem-solution steps had proven most consequential and most often result in refusals. Applicants and agents prosecuting claims in these areas should expect examiners to revisit prior objections framed under the retired approach, and should reassess pending office actions that relied on the old framework.
We are already applying the March 2026 practice notice in active prosecution files, including revisiting outstanding office actions issued under the prior guidance, and we can assess what the change means for a specific pending application.