Supreme Court upholds Janssen dosing patent while preserving medical-treatment exclusion

The Supreme Court of Canada has upheld Janssen’s patent for dosing regimens of a long-acting schizophrenia drug while reaffirming that professional medical skill and judgment cannot be patented.

In Pharmascience Inc. v. Janssen Inc., 2026 SCC 26, decided July 17, 2026, all nine judges dismissed Pharmascience’s appeal. A seven-judge majority maintained the exclusion for methods of medical treatment and explained how courts should apply it. Two judges agreed that the patent survived but would have abandoned that general exclusion.

The result leaves the challenged patent intact. It does not mean that every drug-dosing regimen is patentable, or that any involvement of a doctor makes an invention unpatentable.

A dispute over how a drug is administered

Janssen developed a long-acting injectable formulation of paliperidone palmitate, marketed as INVEGA SUSTENNA, and dosing regimens intended to achieve an optimal concentration of the medication in patients over time. The reasons describe years of research, clinical trials and setbacks before the company arrived at the regimen underlying Canadian Patent No. 2,655,335.

The patent, issued in September 2016, includes initial injections followed by monthly maintenance doses. It specifies different regimens for patients with and without impaired kidney function. Its claims cover uses of a drug-delivery system as well as products, including prefilled syringes and preparations adapted to the regimens.

Pharmascience sought approval for a generic version. The resulting litigation dealt separately with infringement and validity. The lower courts had already found that its proposed product would infringe the patent; infringement was not before the Supreme Court. The appeal concerned only whether the patent was invalid because it claimed an unpatentable method of medical treatment.

Both sides proposed broader changes

Pharmascience argued that a patent governing how and when a drug is administered should be treated as a method of medical treatment. It also linked its proposed approach to concerns about extending drug monopolies through successive patents.

Janssen took the opposite position. It argued that the exclusion for medical-treatment methods had lost its legal foundation when Parliament repealed a provision restricting pharmaceutical patents in 1993. Alternatively, it said the exclusion should be confined to non-economic activities unrelated to commercial products.

Justice Jamal, writing for the majority, rejected both approaches. The exclusion continued to rest on the interpretation of “invention” in section 2 of the Patent Act and the established rule against patenting professional skills. In the majority’s view, medical professionals already have obligations to use and share their skills for patients’ benefit; granting exclusive patent rights over those skills would not serve the legislation’s purpose of encouraging invention.

The majority also rejected a sweeping how-and-when test. Such a rule could catch patents for new uses of existing drugs that the Court had previously upheld. Concerns about improperly extending a patent’s life could instead be addressed through the distinct rules against double patenting. No such challenge was made in this case.

The focus is the invention, not the decision to prescribe it

The central question is whether the claimed subject matter amounts to professional medical skill and judgment. Courts must interpret the claims in context and examine their substance rather than simply accepting the form in which they are drafted.

The majority identified three useful considerations. First, a doctor’s judgment in deciding whether a treatment suits a patient, or remains suitable during monitoring, generally does not make the invention itself unpatentable. Otherwise, the exclusion could reach almost any drug.

Second, a treatment that must be tailored to individual patients is more likely to involve the professional judgment protected by the exclusion. Third, an innovation that a medical professional would ordinarily develop or improve while treating patients is more likely to fall within that professional field. These are guides, not an exhaustive checklist or automatic rules.

The Court also rejected a rigid distinction between fixed and variable dosages. Whether a patent specifies one dose or a range may help illuminate the evidence, but it does not decide the issue. Nor does inclusion on the regulatory patent register establish that a dosing patent is valid.

Why Janssen’s patent survived

The trial judge’s findings supported the conclusion that, once a physician selected one of Janssen’s regimens, implementing it did not require the relevant professional skill and judgment. The claims taught fixed doses, intervals and injection sites.

The choice between the two regimens turned on kidney function. The majority treated that binary distinction as insufficient to make the invention an unpatentable medical-treatment method. It also relied on the trial judge’s findings that the permitted dosing windows and alternative maintenance-injection sites offered flexibility without significant clinical differences. Pharmascience had not established an error warranting interference with those findings.

Agreement on the result, disagreement on the rule

Justices O’Bonsawin and Moreau would also have upheld the patent, but considered the general medical-treatment exclusion outdated and inconsistent. They would have assessed these inventions under the ordinary statutory requirements, including novelty, non-obviousness and utility. In their view, the utility requirement could prevent patents over methods whose results depend on subjective professional skill and cannot reliably be reproduced.

That approach did not command a majority. The governing reasons preserve the medical-treatment exclusion while requiring a fact-specific assessment of each claimed invention.

The Court dismissed the appeal without costs. Its ruling resolved the patentable-subject-matter challenge, not a damages claim or a new determination of infringement. The practical boundary remains between protecting a medical innovation and monopolizing the professional judgment used to treat patients.