Pharmascience Inc. v. Janssen Inc. — SCC Rules Pharmaceutical Dosing Regimens CAN Be Patented If They Don’t Require Medical Judgment (2026 SCC 26)

Background

This landmark case asked the Supreme Court of Canada to decide whether pharmaceutical dosing regimen claims constitute unpatentable “methods of medical treatment” or patentable subject matter under the Patent Act, RSC 1985, c P-4. The dispute centered on Janssen Inc.’s patent for INVEGA SUSTENNA, a long-acting injectable formulation of paliperidone palmitate used to treat schizophrenia. The patent claimed a specific dosing regimen — an initial two-dose loading phase followed by a monthly maintenance dose — that achieved therapeutic drug levels more rapidly than prior long-acting antipsychotics.

Pharmascience Inc., a generic drug maker that sought to launch a competing paliperidone palmitate product, challenged Janssen’s patent on the ground that the claimed dosing regimen was a method of medical treatment and therefore unpatentable under the longstanding rule from Tennessee Eastman Co. v. Canada (Commissioner of Patents), [1974] SCR 111. The Federal Court and the Federal Court of Appeal (2024 FCA 23) both held the claims were patentable, reasoning that the specific dosing schedule was a “vendible product” rather than a pure method of medical treatment. Pharmascience appealed to the Supreme Court, which heard the case on October 9, 2025.

The Court’s Holding

The Supreme Court dismissed Pharmascience’s appeal 7-2, upholding Janssen’s dosing-regimen patent while simultaneously reaffirming — and refining — the rule that methods of medical treatment are unpatentable in Canada.

Writing for the majority, Justice Jamal confirmed that Tennessee Eastman‘s exclusion of methods of medical treatment from patentable subject matter remains good law in Canada. The Court rejected the dissent’s invitation to overrule it, noting that the exclusion reflects Parliament’s intent to preserve physicians’ freedom to exercise their clinical judgment without fear of patent liability. However, the majority held that not every claim touching on medicine or therapeutics is automatically disqualified. The “ultimate question,” Justice Jamal wrote, is whether the claimed subject matter “amounts to professional medical skill and judgment” — and that inquiry is guided by three factors: (1) whether implementing the claimed regimen requires the exercise of professional skill or judgment; (2) whether the claimed regimen is tailored to the individual patient; and (3) whether medical professionals are expected to develop or improve upon the claimed regimen.

Applying that test to Janssen’s claims, the majority found the dosing regimen patentable. Once a physician selects which paliperidone palmitate regimen to prescribe, the specific dosing intervals and loading doses are defined by the patent with enough precision that no further professional skill or judgment is required to carry them out. The patent does not monopolize medical decision-making; it monopolizes a specific pharmaceutical schedule. The dissent (O’Bonsawin and Moreau JJ.) would have gone further, holding that the Tennessee Eastman exclusion is “a relic of another age” that should be abandoned and that methods meeting the standard Patent Act criteria of novelty, utility, and non-obviousness should be patentable regardless of whether they involve medical practice.

Key Takeaways

• Methods of medical treatment remain unpatentable in Canada. The SCC unanimously declined to abolish the exclusion, even as two justices argued for its elimination. Brand-name pharmaceutical companies cannot patent the act of physician judgment itself.
• Specific dosing regimens CAN be patented if they do not require clinical judgment to implement. The new three-factor test provides a workable framework: claims are patentable if a nurse or patient can follow the prescribed schedule mechanically, without the physician needing to individualize or modify the regimen in real time.
• A 2-justice dissent signals ongoing pressure on the exclusion. If the composition of the Court shifts, the Tennessee Eastman rule may face further challenge. Pharmaceutical patentees should monitor this space closely.
• Canadian patent practice diverges further from U.S. practice. In the United States, method-of-treatment claims are presumptively patentable under 35 U.S.C. § 101 (subject to the separate Mayo/Alice framework). Canada’s categorical exclusion creates a distinct risk profile for pharma patent portfolios that span both jurisdictions.

Why It Matters

Pharmascience v. Janssen is the Supreme Court of Canada’s most significant patent-eligibility ruling in decades and will immediately shape pharmaceutical patent strategy across the country. Generic drug makers now have a clear but narrow window: dosing regimens that are rigid and standardized will be patentable and can extend market exclusivity beyond the underlying compound patent, while regimens that require physician interpretation or individualization remain challengeable as unpatentable methods of medical treatment.

The decision also has implications for medical device, diagnostics, and digital health companies whose products involve step-by-step clinical protocols. Those seeking Canadian patent protection for algorithm-driven treatment recommendations, personalized medicine protocols, or dosing calculators should carefully map their claims against the three-factor test. Whether the claimed steps can be followed mechanically — without the intervention of professional medical judgment — will now be the central question in Canadian patent prosecution and litigation involving any claim that touches on how physicians treat patients.