Written By: Chris Chiavatti (IP Lawyer)
On September 19, 2024, the Supreme Court of Canada granted leave in Pharmascience Inc v Janssen Inc et al [“Janssen”], giving the Supreme Court an opportunity to weigh in whether certain dosing regimens are unpatentable methods of medical treatment in Canada.
Canadian case law prevents methods of medical treatment from being patented. However, medical use claims (e.g., the use of Compound X to treat Disease Y) may be patentable, provided that they do not require or limit the exercise of skill and judgment by a physician. The distinction between a non-patentable method of medical treatment and a patentable use claim is often a fine line. As would be expected, this fine line leads to frequent disputes between applicants and CIPO and is a frequent subject of litigation for pharmaceutical patents. Janssen is yet another example of the courts navigating this distinction.
In Janssen, Canadian Patent No. 2,655,355 is at issue, broadly relating to the treatment of schizophrenia with a long-acting, injectable formulation of paliperidone palmitate marketed in Canada as INVEGA SUSTENNA™.
At first instance, the Federal Court identified four broad groupings of claims:
- Claims 1 to 16, pertaining to prefilled syringes for administration according to the following dosage regimen:
- a first loading dose of 150 mg-eq of paliperidone (or 100 mg-eq for a renally impaired patient) to be administered on Day 1;
- a second loading dose of 100 mg-eq (or 75 mg-eq for a renally impaired patient) to be administered one week ±2 days after the first loading dose; and
- a maintenance dose of 75 mg-eq (or 50-mg-eq for a renally impaired patient) to be administered monthly ±7 days after the second loading dose and thereafter.
- Claims 17 to 32, pertaining to “use of a dosage form of paliperidone … for treating a psychiatric patient in need of treatment for schizophrenia” according to the dosage regimen above;
- Claims 33 to 48, pertaining to “use of paliperidone … for the preparation of a medicament” for administration to a patient in need of treatment, the medicament comprising the above dosage regimen; and
- Claims 49 to 63, pertaining to a dosage form of paliperidone palmitate for administration to a patient in need of treatment according to the above dosage regimen.
The Federal Court decided that Groups I, III, and IV were all directed to a “vendible product” (i.e., the prefilled syringe, the medicament, and the dosage form). Thus, these groups were, by definition, not directed to unpatentable methods of medical treatment.
Group II was deemed to be directed to a medical use, but not a method of medical treatment. Previous cases had found that dosage ranges could improperly require the exercise of skill and judgment of a physician. Pharmascience argued that the date windows for administering the second and subsequent doses made these claims into a method of medical treatment. Similarly, Pharmascience argued that the different dosage regimen for renally impaired patients requires a physician to exercise skill and judgment.
However, the Federal Court held that the date windows and dosage regimen for renally impaired patients did not require skill and judgment. Instead, these claims merely required a physician to implement the claimed dosage regimen, and there was no clinical implication to when in the date window a dose was administered.
Pharmascience appealed the Federal Court’s finding that the claims were not directed to methods of medical treatment. The Federal Court of Appeal agreed that Groups I, III, and IV were directed to vendible products and thus could not be methods of medical treatment. The Federal Court of Appeal also agreed that a dosing regimen with inbuilt flexibility did not automatically make the use claim into a method of medical treatment. Rather, the focus of the analysis was on whether the skill and judgment of a physician was implicated. Again, the Federal Court of Appeal agreed that the dosage windows did not require the exercise of clinical judgment, and were present merely to provide flexibility in administration.
The grant of leave by the Supreme Court ensures that the Supreme Court will weigh in on the distinction between unpatentable methods of medical treatment and patentable medical uses. The Supreme Court’s granting of leave in a patent case is also rare, with the Court not having issued a patent-related decision since Nova Chemicals Corp v Dow Chemical Co in November 2022. BRION RAFFOUL LLP will keep stakeholders apprised of developments in this case as they arise.
The continuing evolution of Canadian law regarding methods of medical treatment reveals many potential pitfalls for applicants. Thus, it is critical to have experienced Canadian counsel prosecuting biomedical patent applications. For further information, please contact our experts at BRION RAFFOUL LLP.
