The Supreme Court of Canada is poised to deliver a potentially transformative ruling on pharmaceutical patent law when it hears arguments in Pharmascience Inc. v Janssen Inc. on October 9, 2025. The case addresses a fundamental question that has long divided courts and industry: whether patents can validly claim methods of medical treatment, particularly dosing regimens for pharmaceutical products.
The Central Dispute
The proceeding involves a challenge to Janssen's "335 Patent," which was found to be valid and infringed by the Federal Court. Pharmascience advanced the single issue that the claims of the 335 Patent were invalid as they claimed a "method of medical treatment," which they argued is not permissible under the Patent Act.
The Federal Court of Appeal rejected Pharmascience's appeal, concluding that determining whether a patent impermissibly claimed a method of medical treatment was based upon whether "use of the invention (i.e., how to use it, not whether to use it) requires the exercise of skill and judgment." The court found that claims which relate to a "commercial offering," or "trade, industry or commerce" are permissible.
Competing Legal Arguments
Pharmascience's Position
Pharmascience seeks to have Janssen's 335 Patent declared invalid, arguing that methods of medical treatment are not patentable as established by the Supreme Court of Canada in the 1974 decision of Tennessee Eastman v Commissioner of Patents. The company proposes a three-step test for determining whether a patent claims a method of medical treatment:
- Construing the claim in accordance with normal procedures
- Identifying whether any essential elements can properly be said to be "therapeutic" or "medical"
- Identifying whether any of those essential elements relate to how and when a drug or treatment is to be administered by a medical practitioner
According to Pharmascience's submissions, if the answers to steps two and three are "yes," then the claims are invalid for claiming unpatentable subject matter.
Janssen's Counter-Arguments
Janssen opposes this position, submitting that either the Patent Act does not prohibit claims to methods of medical treatment, or if any such prohibition exists, it is limited to methods involving the exercise of professional skills and does not extend to claims to commercial offerings.
Janssen argues that the historical basis for excluding claims to methods of medical treatment, stemming from the Tennessee Eastman decision, is based upon a provision of the Patent Act that has since been repealed. As patent law is wholly statutory, Janssen submits that there is no longer any valid legal basis to preclude claims for a method of medical treatment.
Industry Stakeholder Perspectives
Four interveners have been granted leave to make submissions, representing diverse perspectives across the pharmaceutical ecosystem.
The Canadian Generic Pharmaceutical Association argues that dosing regimens are merely methods of treating patients and do not constitute an "invention" within the meaning of the Patent Act. The CGPA asserts that granting patents for dosage regimens unduly extends the monopoly over a drug and prejudices Canadians by contributing to higher prices for medicines.
Conversely, the Canadian Organization for Rare Disorders submits that the Patent Act permits claims directed to methods of medical treatment, arguing that such methods qualify as an "invention" as defined in the Patent Act and are not precluded by any express statutory provision.
Three Canadian physicians involved in treating patients with dosing regimens similar to those described in the 335 Patent argue that new medicines and dosing regimens are not developed by physicians, but instead are the result of commercial innovation by pharmaceutical manufacturers. These physician interveners submit that recognizing the patentability of dosing regimens is essential to incentivizing pharmaceutical companies to develop new treatments for the betterment of Canadian patients.
Current Legal Framework
Section 2 of the Patent Act defines "invention" as "any new and useful art, process, machine, manufacture or composition of matter, or any new and useful improvement in any art, process, machine, manufacture or composition of matter." While subsection 27(8) provides that no patent shall be granted for any "mere scientific principle or abstract theorem," the current version of the Patent Act does not explicitly state that methods of medical treatment are unpatentable.
In the pharmaceutical context, courts have typically drawn a line between fixed dosages and dosing schedules (patentable) and dosage and dosing schedule ranges (generally unpatentable). However, the Federal Court of Appeal questioned this distinction, noting that it does not necessarily determine whether a drug is a vendible product.
Potential Outcomes and Industry Impact
The Supreme Court's decision is expected to attract close attention from both the intellectual property bar and the Canadian pharmaceutical industry. One possible path is for the Supreme Court to adopt an approach similar to its reasoning in AstraZeneca v Apotex, where it abolished the "promise doctrine" on the basis that patent law is wholly statutory and there was no basis in the text of the Patent Act to support such an elevated utility requirement.
Should the Supreme Court abolish the prohibition against claiming methods of medical treatment, it would eliminate significant uncertainty surrounding an argument that has been inconsistently applied by the Federal Court to invalidate otherwise novel, inventive, and useful patents.
Conversely, a finding that claims to methods of medical treatment are precluded by the Patent Act, and any new test crafted by the Court on how to apply that preclusion, will likely prompt continued legal debate in future patent litigation over how this preclusion is to be classified against various types of patent claims commonly used in pharmaceutical patents.
The hearing will be available by webcast, starting at 9:30 a.m. Eastern Time, with information available on the Supreme Court of Canada's "live hearing" page on the day of the hearing.
