Dusome v Canada: What the Federal Court decision means for patentable subject matter

In Dusome v. Canada (Attorney General), 2025 FC 1809, the Federal Court reviewed the Commissioner of Patents' decision refusing to grant Canadian Patent Application Number 2,701,028 on the basis that it was a “mere scientific principle or abstract theorem.” This decision has important implications for how CIPO assesses subject‑matter eligibility, particularly for computer‑implemented inventions, business methods, and game‑related claims.

In this article, we outline the reasons why the Federal Court set aside the Commissioner’s refusal of the ‘028 Application and assess the guidance Dusome provides on purposive construction, identifying patentable subject matter, and the definition of “art” particularly as it relates to computer-implemented inventions.

Subject matter eligibility and computer-implemented inventions

Subject matter eligibility is a requirement in patent law that determines whether an invention qualifies for patent protection. Before an invention can be evaluated for novelty, inventive step, or industrial applicability, it must first fall within the applicable categories of patentable subject matter.

The criteria and frameworks for assessing subject matter eligibility vary from one jurisdiction to another, particularly for computer-implemented inventions. While different jurisdictions utilize different methodologies for examination, their outcomes often converge. However, within each jurisdiction there are nuances that must be effectively navigated as part of the patenting process which can involve filing corresponding applications in multiple jurisdictions.

In the United States, the threshold requirement for patent protection is set out in Section 101 of Title 35 of the U.S. Code, which defines eligible subject matter as "any new and useful process, machine, manufacture, or composition of matter, or any new and useful improvement thereof." This is a rather broad definition, and depending on how a claim is framed, computer-implemented inventions could easily fall into one or more of these categories. However, Section 101 is not without its limits, and the breadth of what constitutes eligible subject matter has been further distilled based on judicial exceptions defined by the U.S. Supreme Court, which include abstract ideas, natural phenomena, and laws of nature. These judicial exceptions are often the biggest hurdle that applicants of computer-implemented inventions face in the United States in terms of whether the invention qualifies as patent eligible, particularly with regard to abstract ideas.

In Europe, the European Patent Convention (EPC) sets out the requirements for patentable subject matter. A patent can be granted in any field of technology, provided that the invention is new, involves an inventive step, and is susceptible to industrial application. However, the EPC does not regard computer programs as inventions if claimed as such, and methods for performing mental acts, playing games, doing business, and presenting information are explicitly excluded from patentability altogether. Under the approach of the European Patent Office (EPO), a claim directed to a computer program will not be excluded from patentability under Article 52 of the EPC if it contains at least one feature that has technical character. In this regard, it is sufficient that a claim is directed to a device or a method implemented in a computer to avoid exclusion from patentability. The Supreme Court of the United Kingdom recently adopted this approach in a case involving an AI-related patent application.

History of computer-implemented inventions in Canada

In Canada, the requirement for patentable subject matter is set out in section 2 of the Patent Act. An "invention" is defined as "any new and useful art, process, machine, manufacture or composition of matter, or any new and useful improvement" thereof. Additionally, subsection 27(8) provides that "no patent shall be granted for any mere scientific principle or abstract theorem."

While this may seem permissive, the application of section 2 of the Patent Act to computer-implemented inventions is more complicated:

• In 1982, the Federal Court of Appeal addressed a patent application for collecting, recording, and analyzing seismic data using a computer programmed according to a mathematical formula. The application failed because the only novel aspect of the claimed invention was the mathematical formula itself, which constituted a "mere scientific principle or abstract theorem" prohibited by subsection 27(8). This case established that where a computer serves merely as a tool to manipulate information faster than a human could, without contributing anything inventive beyond the underlying algorithm, the claimed invention is not patentable subject matter.
• Later that year, in a case involving chemical compositions, the Supreme Court of Canada established the foundational "practical application" test that would become critical for assessing computer-implemented inventions. In particular, it was held that practical applications of scientific principles and abstract theorems can constitute patentable inventions.
• Nothing significant happened in this area of law until 2011, when the Federal Court of Appeal issued the pivotal "one-click" decision. The Federal Court of Appeal established several key principles:
  • The Commissioner's identification of the actual invention must be "grounded in a purposive construction of the patent claims."
  • "No Canadian jurisprudence determines conclusively that a business method cannot be patentable subject matter."
  • A business method that is not itself patentable because it is an abstract idea does not automatically become patentable merely because it has a practical embodiment or application.
  • The understanding of the "physicality requirement" for patentable subject matter may need to adapt as technology advances, but cannot be met merely by the fact that the claimed invention has a practical application.
  • Once purposive construction is completed, the assessment of patentable subject matter, obviousness, novelty, utility, and excluded subject matter "need not follow any particular order."
• In response to this decision, the Canadian Intellectual Property Office (CIPO) addressed patentable subject matter by identifying a problem and a solution to the problem with guidance from an “examiner’s understanding of the common general knowledge in the art and by the teachings of the description.” The identification of the problem and solution is then used by the examiner to identify superfluous (non-essential) elements of the claim that are not involved with the identified solution. These superfluous (non-essential) elements would not be considered part of the invention and thus not considered in determining whether the claim included patentable subject matter. This approach resulted in many computer-implemented inventions being declared non-statutory under section 2 of the Patent Act.
• In a series of decisions in 2020 and 2023, the Federal Court and Federal Court of Appeal found that this problem-solution approach was not proper (Choueifaty and Benjamin Moore). In response, CIPO updated its approach away from a problem-solution approach to one which identifies an “actual invention”, allowing elements that were not part of the “actual invention” to be not considered.

In the Dusome decision, the Federal Court addressed the current “actual invention” approach used by CIPO.

The Dusome decision

The ‘028 Application is directed to a method of playing a wagering poker game, playable with physical cards or on a computer.

The Commissioner refused the ‘028 Application on the grounds that the claimed invention did not meet the requirements of section 2 of the Patent Act and claimed subject matter that was a mere scientific principle or abstract theorem contrary to subsection 27(8) of the Patent Act. The patent applicant appealed to the Federal Court.

The Federal Court held that the Commissioner erred as follows:

Error 1: Purposive construction

The Commissioner erred in law by failing to construe the ‘028 Application claims consistent with the principles of purposive construction or as described in CIPO’s own examiner guidelines, PN2020‑04.

The Commissioner had declared all elements in claims 1-24 essential without justification, instead of isolating and giving meaning to the descriptive language in the representative claim, construing the claim through the eyes of the person of skill in the art for both meaning and novelty, and sufficiently engaging with the disclosure.

This error led to an improper identification of the actual invention of the ‘028 Application.

Error 2: Assessing patentable subject matter by a free actual invention inquiry

The Commissioner erred in law by assessing patentable subject matter by reference to the Commissioner’s own view of the “actual invention”. This approach was previously rejected by the Federal Court of Appeal.

Error 3: Stripping away physical elements and collapsing the invention into new knowledge

In identifying the “actual invention,” the Commissioner removed the physical card play and computer implementation as “generic”, leaving only rules and algorithm, which led to the conclusion that there was no physicality and that it was an abstract theorem under subsection 27(8).

In this regard, the Commissioner erred in law by failing to determine where the discovery lies based on a proper claim construction and improperly equated the “actual invention” with only the new knowledge.

Error 4 — Applying an improper definition of “art”

The Commissioner erred in law by using the incorrect test for patentable “art”. It was an error to conclude that in order to meet the definition of “art”, the invention had to “cause a change in the character or condition of a physical object”.

By insisting on a “change in something material”, the Commissioner applied a narrower and incorrect scope of “art”.

Next steps for the ‘028 Application

The Federal Court noted the Applicants have prosecuted the ‘028 Application since 2008 and that any possible monopoly would likely have little value even if they succeeded on appeal and re-examination. On that basis, the ‘028 Application was remitted for expedited re-examination.

The Dusome decision has not been further appealed, and the deadline to appeal has passed.

Accordingly, the next step would be for the Patent Appeal Board to reconsider the 028’ Application and provide the Commissioner with a recommendation. The Commissioner will likely issue a decision allowing or further refusing the application.  While timing at CIPO has been somewhat inconsistent lately, we expect a decision by the summer or fall.

Takeaways for subject matter eligibility

The Dusome decision carries significant implications for CIPO, in particular, for the manner in which computer-implemented inventions are treated in the Manual of Patent Office Practice (MOPOP). In allowing the appeal, the Federal Court identified multiple legal errors in CIPO's approach to subject-matter patentability:

First, it would appear that section 17.03.09 of MOPOP, which states that a manner of playing a game or sport does not solve a practical problem and is therefore non-statutory, would need to be revised. In Dusome, the court held that this reliance is contrary to the clear finding that any refusal of a patent application on the basis of non-patentable subject matter must be grounded in the Patent Act itself, and there is no per se prohibition on patenting subject matter related to the rules of a card game.

More significantly, CIPO must also reconsider how MOPOP guides examiners on the "actual invention" question. In particular, the Commissioner cannot allow an inquiry into what an “actual invention” is to override the importance of purposive construction upon which a proper assessment is ultimately based. The Dusome decision clarifies that the actual invention consideration should be part of purposive construction and should allow the Commissioner to ask whether the only inventive aspect is an unpatentable abstract algorithm, or whether the discovery is one of a number of essential elements in a novel combination. Although the Dusome decision involves a card game method, its reasoning extends to computer-implemented inventions more broadly. The Court emphasized that while unpatentable subject-matter cannot be saved by merely programming it into a computer, examiners must keep an open mind and not hastily conclude that claimed subject-matter is unpatentable simply because it involves the use of conventional computer technology. This principle may result in further revisions to MOPOP's guidance on software and computer-implemented inventions.

The Dusome decision represents a significant rebuke of CIPO's current approach to subject-matter patentability for method claims involving games, business methods, and potentially other categories of inventions. CIPO will need to undertake a comprehensive review and revision of MOPOP to eliminate categorical exclusions, strengthen guidance on purposive construction, and clarify the proper role of the "actual invention" inquiry. Until these revisions become consistent with the definition of "art" as laid out by the Supreme Court of Canada almost 45 years ago, examiners and applicants alike face uncertainty regarding how CIPO will approach similar applications going forward.