Appeal Court Clarifies Patentability Of Methods Of Medical Treatment

In Canada, the prohibition against patenting methods of medical treatment has been a subject of legal ambiguity. Historically, case law suggested that claims to fixed dosages were patentable, while claims to dosage ranges were often deemed unpatentable as methods of medical treatment.

The decision issued by the Federal Court of Appeal ("FCA") in Pharmascience v Janssen earlier this year offers additional perspective and commentary on what constitutes patentable subject matter in the context of methods of medical treatment.

Background

Janssen owns Canadian Patent No. 2,655,335 (the "335 Patent"), which focuses on a specific dosing regimen for INVEGA SUSTENNA, a treatment for schizophrenia. This regimen includes first and second loading doses, followed by monthly maintenance doses. The 335 Patent contains four sets of claims:

1. prefilled syringes adapted for administration according to the claimed dosing regimens;
2. the use of a dosage form according to the claimed dosing regimens;
3. the use of paliperidone palmitate to manufacture a medicament adapted for administration according to the claimed dosing regimen; and
4. a dosage form adapted for administration according to the claimed dosing regimens.

Pharmascience challenged the 335 Patent, arguing the claims constitute an unpatentable method of medical treatment.

The Trial Judge's Ruling

The trial judge held that this challenge was only relevant to the claims directed to the use of a dosage form according to the claimed dosing regimens; the other claims were all directed to a vendible product, which does not constitute a method of medical treatment. The trial judge upheld Janssen's patent as valid, finding that it encompassed fixed dosage amounts. The judge also noted that to the extent there were choices concerning dosing windows and injection sites, these choices had no clinical implications and did not interfere with a physician's exercise of skill and judgment. Therefore, the claims were not categorized as a method of medical treatment.

The Appeal

On appeal, Pharmascience contended that all claims of the 335 Patent, due to their inclusion of a dosing regimen as an essential element, should have been subjected to the method of medical treatment analysis.

The FCA's decision provides a crucial takeaway: including a dosing regimen does not inherently render a claim unpatentable. The Court noted that a claim may pertain to a vendible product, even if it includes a dosing regimen as an essential element. The pivotal question is whether the use of the invention requires the physician's professional skill and judgment. The Court emphasized that a claim will only constitute a prohibited method of medical treatment if it goes to how to treat a patient, as opposed to whether to treat a patient. A patent claim with a dosing regimen can still be patentable if it does not necessitate the exercise of a physician's professional skill and judgment.

The FCA noted that the variability present in the 335 Patent was not problematic as it did not interfere with a physician's exercise of skill and judgment. Essentially, the discretion in applying the treatment regimen under this patent was a question of "whether" to use the drug, as opposed to "how" to use it. As the 335 Patent did not impinge on the physician's discretion in deciding how to treat the patient, it was deemed not to be a method of medical treatment.

Two Key Clarifications by the FCA

1. A claim that includes a dosing regimen as an essential element can be a patentable claim to a vendible product.
2. The patentability of a claim to a dosing regimen depends on whether the use of the invention requires the exercise of professional skill and judgment. A claim to a dosing regimen can still be patentable if no professional skill and judgment is involved in administering the dosing regimen.

Commentary

The FCA decision reflects the evolving nature of patent law, broadening the scope for patenting pharmaceutical inventions that involve dosing regimens. It introduces greater flexibility for pharmaceutical and biotech companies in patent drafting, moving beyond the strict dichotomy of fixed versus variable dosing regimens. However, this shift reduces the predictability of patent litigation outcomes. Future cases will no longer hinge on the distinction between fixed and variable doses. Instead, they will be assessed based on their specific facts and evidence, with a particular focus on the physician's involvement in the implementation of the claimed dosing regimen.

However, the implications of the FCA decision may change, as Pharmascience recently submitted an application to the Supreme Court of Canada ("SCC") requesting permission to appeal the decision. If the request is granted, the SCC will have the chance to confirm or clarify the approach to assessing the patentability of methods of medical treatment.

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