SUPREME COURT OF CANADA UPHOLDS PATENTABILITY OF DOSING REGIMENS

The Supreme Court of Canada released its decision in Pharmascience Inc. v Janssen Inc., 2026 SCC 26 on July 17, 2026, dismissing Pharmascience’s appeal and upholding the validity of Janssen’s Invega Sustenna dosing regimen patent.

Pharmascience had argued that the lower courts erred in determining that Janssen’s patent, directed at dosing regimens for long-acting injectable formulations of paliperidone palmitate for use in treating schizophrenia, was not a method of medical treatment.

Pharmascience submitted that the Court should adopt a “how and when” test, in that claims directed to “how” and “when” a physician administers a drug or treatment are unpatentable methods of medical treatment. Conversely, Janssen submitted that the prohibition against methods of medical treatment rested on former s. 41(1) of the Patent Act, or alternatively, that any prohibition should not extend to medical activities related to commercial products.

Writing for the majority, Justice Jamal rejected Pharmascience’s proposed test and found that drug-dosing regimens can be patentable subject matter in Canada. The majority was not prepared to abolish the method of medical treatment prohibition, as the minority would have, finding that even with the repeal of s. 41(1) of the Patent Act, inventions to methods of medical treatment remain unpatentable because of the principle that professional skills are not patentable, and because Canadian courts have continued to apply the prohibition after the repeal of s. 41(1).

The majority provided non-exhaustive guidance on how to distinguish between patentable medical innovations and patents which seek to “fence in” professional skill and judgment, emphasizing that the assessment is “factually suffused”. The analysis begins by construing the patent’s claims, followed by an assessment of “the real subject matter of the claim” without putting the form in which the claim is drafted over its true substance. The majority provided three non-exhaustive points to help guide the analysis.

1. The Court stated that the analysis should not consider whether professional skill and judgment is needed to choose to treat a patient with the claimed invention, as medical judgment is often required in deciding whether any drug or treatment is appropriate for a given patient. Similarly, it is irrelevant as to whether a medical professional has to monitor a patient while on the drug or treatment.
2. The Court stated that the more the practice of an invention requires tailoring the invention to the particular circumstances of a given patient, the more likely it is that the invention is a method of medical treatment – but that this is also not the determinative factor in the analysis. They further stated this also means that if the subject matter of the invention can be applied generally to a broad class of patients, the less likely it is for the invention to be a method of medical treatment.
3. The Court provided that the more a medical professional would be incentivized to develop or improve a given subject matter in the course of their professional practice, the more likely it is that the invention is unpatentable as a method of medical treatment.

The Court found that the trial judge correctly focused on professional skill and judgment and that there was no error in the judge’s findings that aspects of the dosing regimen requiring physician choice (i.e. whether to use a separate regimen for renally impaired patients, as well as choices around dosing windows and monthly maintenance dose injection sites) did not amount to exercising skill and judgment. Thus, the Court concluded the trial judge’s findings disclosed no reviewable error, and dismissed Pharmascience’s appeal.

Concurring reasons were provided by Justices O’Bonswain and Moreau. They agreed that Pharmascience’s appeal should be dismissed, however they disagreed with the majority that methods of medical treatment are inherently prohibited under Canadian law. Justices O’Bonswain and Moreau found that, following the repeal of s. 41(1), the precedential value of the Supreme Court of Canada’s decision in Tennessee Eastman is “doubtful”, and that post-repeal comments on methods of medical treatment by the Court in other decisions were in obiter. They agreed with the parties that there have been practical issues in applying the method of medical treatment doctrine and skill and judgment test. They concluded that methods of medical treatment are not inherently unpatentable and should be assessed in the same manner as any other claimed invention. They also commented that the utility requirements for patentability would safeguard against the patenting of many methods of medical treatment, reasoning that inventions that depend upon one’s skill and judgment would be deemed inoperable, as the “actual result” for which they were designed is uncontrollable or irreproducible due to the significant subjective human contribution required to operate the invention.

Stakeholders await the lower courts’ application of this decision.