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Claims to Dosing Regimens May Not Be Prohibited Methods of Medical Treatment: A Question of “Whether” and “How”

In Pharmascience v Janssen, the Federal Court of Appeal (Locke JA writing for the Court) held that the claims in Janssen’s patent to a dosing regimen are not prohibited as a method of medical treatment.

Pharmascience v Janssen, 2024 FCA 23  

The patent at issue in this case (“335 Patent”) was the subject of two recent Federal Court of Appeal decisions (see our blog post here). The 335 Patent claims a dosing regimen for treating schizophrenia that required patients to receive:

  1. A first loading dose of 150 milligrams equivalent [mg-eq.] of paliperidone palmitate administered into the deltoid muscle on Day 1 of treatment;
  2. A second loading dose of 100 mg-eq. of paliperidone palmitate administered into the deltoid on Day 8 ± 2 days; and
  3. Maintenance doses of 75 mg-eq. of paliperidone palmitate administered into the deltoid or gluteal muscle monthly ± 7 days after the second injection.

The issue in the present appeal was whether the claims of the 335 Patent comprise unpatentable subject matter as being directed to methods of medical treatment.

The Prohibition Against Patenting Methods of Medical Treatment

The patentability of methods of medical treatment has been an unsettled issue in Canada for many years. Until February 1993, the Patent Act was interpreted by the Supreme Court of Canada as prohibiting patents for methods of surgical skill (e.g., Tennessee Eastman ([1974] SCR 111)). The Supreme Court subsequently extended this principle to cover methods of medical treatment that purported to monopolize a physician’s skill and judgment (e.g., Shell Oil ([1982] 2 SCR 536) and Welcome Foundation (2002 SCC 77)).

After the statutory prohibition was repealed, Courts struggled to find a logical dividing line between claims to therapeutic uses of pharmaceutical products (which are patentable) and claims monopolizing areas of professional skill (which are not patentable). Courts often held that claims to the use of “vendible products” and “fixed dosing regimes” were patentable, whereas claims that were not tied to specific products or that required the exercise of discretion by physicians were not patentable. The lack of doctrinal precision caused the case law to develop in an imperfect manner, including many decisions at the appellate level.

Claims to Dosing Regimens may be Patentable

The Court of Appeal held the jurisprudential distinctions between fixed dosing and variable dosing, and between vendible products and therapeutic uses per se, does not necessarily determine the issue of patentability.

Rather, the Court of Appeal held that judges must focus on the distinction between the exercise of skill and judgment in deciding whether to use a claimed invention (this is patentable), and the exercise of skill and judgment in deciding how to use a claimed invention (this is not patentable). In other words, claims are not patentable if they cover areas where it was expected that professional skill and judgment would be required in how the claimed invention is to be used. Thus, the proper inquiry when deciding if a claim to a dosing regimen relates to a method of medical treatment is to ask if the claim covers how a physician will use the claimed invention, rather than covering whether a physician should use the claimed invention.

With regard to Janssen’s 335 Patent in particular, the patent contained three types of claims: claims directed to prefilled syringes, claims to dosage forms, and claims to uses. The Court of Appeal held that claims to prefilled syringes and dosage forms are not prohibited as methods of medical treatment, even where the dosing regimen may be an essential element of the claims. This is because both types of claims are directed to vendible products, which clearly relate to trade, industry or commerce.

As for the claims directed to the use of the medicine using the specific dosing regimen, the Court of Appeal held that the proper question is whether professional skill and judgment was required in how to use the claimed invention. The fact that the use claims of the 335 Patent include a fixed dosage and schedule was a good indication that no such skill and judgment is required. On the other hand, where the claims include a variable dosage and/or schedule, it may be that the physician will have to exercise skill and judgment in how the claimed invention is to be used, which may render the claims unpatentable.

In summary, the Court of Appeal held that claims including a dosing regimen as an essential element are patentable unless a physician must exercise skill and judgment in deciding how to use the claimed invention. Claims that include fixed dosages and schedules are likely patentable since they do not require skill and judgment on how to use the invention. Moreover, claims directed to products, such as prefilled syringes, dosage forms, etc., are patentable because they are vendible products regardless of whether a dosing regimen is an essential element.

Pharmascience has 60 days from the date of the judgment to file an application for leave to appeal to the Supreme Court.