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Federal Court of Appeal affirms paliperidone palmitate claims are not unpatentable methods of medical treatment

Authored byMalcolm Harvey

Update: On April 2, 2024, Pharmascience filed an application for leave to appeal to the Supreme Court of Canada (Docket No. 41209).

In a 2022 decision involving Janssen and Pharmascience, the Federal Court found that the claims of Canadian Patent No. 2,655,335 (335 patent, relating to paliperidone palmitate (Janssen’s INVEGA SUSTENNA)) were not invalid for obviousness or as a method of medical treatment.


On February 1, 2024, the Federal Court of Appeal (FCA) dismissed Pharmascience’s appeal. Per the FCA, whether a claimed dosing regimen is an unpatentable method of medical treatment cannot be based exclusively on whether the dosing regimen is fixed or variable. Rather, the proper inquiry is “whether use of the invention (i.e., how to use it, not whether to use it) requires the exercise of skill and judgment”: Pharmascience Inc v Janssen Inc, 2024 FCA 23.


The claims of the 335 patent relate to dosing regimens for paliperidone. They contemplate administering specified doses of paliperidone into a deltoid muscle on days 1 and 8 and then into a deltoid or gluteal muscle monthly thereafter (i.e., two “loading doses” followed by a “maintenance dose”). In particular:

  • the second loading dose is administered “one week ± 2 days after the first loading dose”; and
  • the maintenance dose is administered “according to a continuous schedule having a monthly ± 7 days dosing interval after the second loading dose”.

In its 2022 decision, the Federal Court distinguished between the “use” and “product” claims of the 335 patent. The use claims related to use of a dosage form according to the claimed dosing regimens. The product claims related to prefilled syringes, use of paliperidone in the preparation/manufacture of a medicament, and a dosage form, each adapted for administration according to the claimed dosing regimens.

The Federal Court stated that a method of medical treatment analysis was relevant in respect of the 335 patent’s use claims but not its product claims. For the use claims, professional skill and judgment would not be required to implement the claimed dosing regimens, as (i) each of the claims taught fixed dose amounts, intervals and injection sites, and (ii) select claim elements that involved choice (e.g., injection site for the maintenance dose) did not have clinical implications. The Federal Court therefore concluded that the claimed subject matter was not a method of medical treatment.

FCA upholds Federal Court’s determination of patentable subject matter

Unpatentable subject matter (i.e., method of medical treatment) was the sole validity issue in dispute at the time of the FCA’s decision. Here, Pharmascience argued that the Federal Court erred in law by:

  1. excluding the 335 patent “product” claims from its method of medical treatment analysis; and
  2. determining patentability based on a dichotomy between fixed and variable dosing regimens.

Before addressing these issues, the FCA reviewed the jurisprudence on the prohibition against patenting methods of medical treatment.

The FCA concluded that the proper inquiry remains whether use of the invention requires the exercise of skill and judgment. However, what is prohibited is the exercise of skill and judgment in deciding how to use the invention (not whether to use the invention). While it is permissible to consider whether a claimed dosing regimen is fixed or variable, this alone cannot determine whether a claim concerns an unpatentable method of medical treatment.  

The FCA then turned to Pharmascience’s arguments, rejecting them as follows:

  • Dosing regimens in product claims: Pharmascience argued that the 335 patent product claims concern a dosing regimen involving ongoing maintenance dosing and should not have been excluded from the Federal Court’s method of medical treatment analysis.

The FCA noted that it was not in dispute that a vendible product is not a method of medical treatment. In addition, it noted that claims containing a dosing regimen as an essential element may still concern a vendible product.

In the FCA’s view, the product claims identified by the Federal Court – relating to pre-filled syringes, use of paliperidone in the preparation of a medicament, and a dosage form – all concerned vendible products and not methods of medical treatment. Despite a suggestion otherwise in its reasons, the Federal Court had in fact considered these claims and found that they related to a vendible product (and were therefore patentable subject matter).

  • Fixed versus variable dosing regimens: Pharmascience argued that the Federal Court erred (i) in describing the relevance of fixed versus variable dosing regimens, and (ii) in characterizing the 335 patent use claims as defining fixed dosages and schedules.
    • The FCA noted in response to the first assertion that, although the Federal Court’s description of the law on fixed dosages and schedules was incomplete, this was not a reviewable error. The Federal Court properly addressed whether use of the claims required the exercise of skill and judgment in deciding how to use the invention.

    • In response to the second assertion, the FCA highlighted the Federal Court’s finding that choices in select claim elements (e.g., scheduling and location of the maintenance dose) did not have clinical implications and would therefore not interfere with a physician’s exercise of skill and judgment. The FCA saw no legal error in this finding and noted that Pharmascience did not assert any error of fact or mixed fact and law.

    The FCA also addressed a sentence in the 335 patent disclosure relating to maintenance dose titration – this was “not of such a nature as to require the Federal Court to conclude that use of the claimed invention demands the exercise of skill and judgment.”

FCA upholds injunction granted by Federal Court

Pharmascience also argued that the injunction granted by the Federal Court was overly broad for covering activities outside of the exclusive rights enumerated in s. 42 of the Patent Act.

The FCA rejected this argument. Pharmascience did not raise the issue in its notice of appeal, and the FCA had granted a similar injunction in a parallel proceeding involving Apotex (and the reasons given in that decision also applied in the present matter).

Pharmascience would need leave from the Supreme Court of Canada to appeal the FCA’s decision.

Should you have any questions, please do not hesitate to contact a member of the Pharmaceutical Litigation Group.

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