Upcoming SCC Decision May Potentially Reshape the Prohibition of Patenting Methods of Medical Treatment in Canada
In Canada, the prohibition against patenting methods of medical treatment is not explicitly set out in the Patent Act, but is considered a judicial interpretation. Consequently, there have been inconsistencies in Canadian law on what constitutes a prohibited method of medical treatment.
On October 9, 2025, the Supreme Court of Canada (SCC) will hear arguments in Pharmascience Inc. v Janssen Inc., et al (Supreme Court File No. 41209)[1] which is centred on this legal issue – whether patents can validly claim a method of medical treatment, and more specifically whether a dosage regimen constitutes a prohibited method of medical treatment.
Briefly, and by way of background, Canadian Patent No. 2,655,335 (the ‘335 patent) relates to long acting injectable paliperidone palmitate formulations for treating schizophrenia and related disorders, under the brand name INVEGA SUSTENNA®.
To achieve an optimum plasma concentration/time profile in a psychiatric patient, the claims of the ‘335 patent involve a specific dosage regimen of paliperidone palmitate with a first loading dose of about 150 milligram equivalent (mg-eq.) followed by a second loading dose of about 100 mg-eq. one week ± 2 days after the first loading dose, and thereafter a maintenance dose of about 75 mg-eq. with a continuous schedule of monthly ± 7 days dosing intervals. Alternative lower dosage amounts are also specified for renally impaired psychiatric patients.
The ’335 patent has four types of claims with a total of 63 claims surrounding the dosage regimen: claims 1-16 are directed to prefilled syringes; claims 17-32 are medical use claims of the dosage forms; claims 33-48 are Swiss-type claims covering the use of paliperidone in the manufacture of a medicament; and claims 49-63 are for the dosage forms. None of the claims are prima facie methods of medical treatment claims.
Pharmascience Inc. sought a Notice of Compliance to market a generic version of INVEGA SUSTENNA®. Janssen commenced an action under subsection 6(1) of the Patented Medicines (Notice of Compliance) Regulations[2] arguing that Pharmascience Inc.’s generic version would infringe the ‘335 patent. Pharmascience Inc. defended the action on several grounds, including that claims of the ‘335 patent are invalid for claiming unpatentable methods of medical treatment.
At the trial level, the Federal Court held that based on the case law, claims to a vendible product (i.e. claims 1-16 and 33-63) are patent eligible, and a method of medical treatment analysis was only relevant to use claims 17-32 of the ‘335 Patent (Janssen Inc. v. Pharmascience Inc., 2022 FC 1218, para 163).[3] In practice, claims directed to a fixed dosage regimen (fixed amounts and fixed dosing schedules) have been considered to be patent eligible. However, if the claims involve a variable dosage regimen which requires a physician’s skill and judgment, the subject matter is generally unpatentable. While acknowledging this fixed vs. variable dichotomy “seems to have a questionable underpinning”[4], the Federal Court concluded that the use claims of the ‘335 patent were not methods of medical treatment. The conclusion was based on the rationale that the specified dosage regimens are of fixed amounts and schedules, and thus no skill and judgement is required that would interfere with or restrict a physician to prescribe the dosing regimen.[5]
Pharmascience Inc. appealed to the Federal Court of Appeal (FCA)[6] alleging that the Federal Court erred by excluding vendible products from the methods of medical treatment analysis, and by determining that the claims of ‘335 patent did not fall within the scope of the methods of medical treatment prohibition based on a dichotomy between fixed and variable dosing regimens.
After a review of the jurisprudence on the prohibition against patenting methods of medical treatment, the FCA unanimously upheld the Trial Judge’s finding that the ‘335 patent contained patentable subject matter. The FCA confirmed that the “product” claims (claims 1-16 and 33-63) are directed to a vendible product that is not a method of medical treatment, noting that a product claim with a dosing regimen as an essential element may still concern a vendible product.[7]
For the “use” claims, the FCA agreed that the Trial Judge properly focused on whether use of the claims required the exercise of skill and judgment.[8] The FCA held that whether a dosage regimen is fixed or variable alone is not determinative of patentable or unpatentable subject matter, and that the proper inquiry for determining whether a claimed subject matter falls under the prohibited methods of medical treatment remains “whether use of the invention (i.e., how to use it, not whether to use it) requires the exercise of skill and judgment”. [9] The FCA cautioned that it is “difficult to provide more detailed guidance than this” for future litigation and allegations of invalidity based on unpatentable methods of medical treatment.[10]
Pharmascience Inc. sought leave to appeal, and SCC granted the leave on September 19, 2024.[11]
While the SCC’s decision is unlikely to follow soon after the hearing in October, it is expected to attract close attention from both the intellectual property community and the pharmaceutical industry because the decision could potentially clarify the framework for assessing the patentability of methods of medical treatment, and may reshape what would constitute to an unpatentable method of medical treatment in Canada.
Please do not hesitate to contact one of our team members if you have questions or concerns regarding patenting methods of medical treatment in Canada.