Patent Appeal Board Allows Dosage Regimen Claims – No Physician Skill Needed
In the recent Commissioner’s Decision Re Amgen Research (Munich) GmbH (2021 CACP 2), the Patent Appeal Board allowed medical use claims reciting a dosage range in Amgen’s Canadian Patent Application 2,633,594 (the 594 application).
It is well known that in Canada, while methods of medical treatment are not patentable subject matter, medical use claims are considered patentable. Nevertheless, there have been several Federal Court decisions1 where a claim directed to the exercise of professional skill or judgment, for instance a claim containing a dosage range, was held to be not patentable.2 Consequently, CIPO issued the 2015 Revised Examination Practice Notice (PN 2015-01), which specified that where an essential element of a medical use claim prevents, interferes with or requires the professional skill of a physician, the claim is considered to encompass a method of medical treatment and is not patentable subject matter under s.2 of the Patent Act.
The claims in questions in the 594 application are directed to an antibody for use in the treatment of B cell non-Hodgkin lymphoma or B cell leukemia, wherein the antibody is for administration for at least 1 week in a daily dose of 10 μg to 80 μg per square meter patient body surface area. In the Final Action, the Patent Office recognised that determination of the duration of the treatment and selecting a dosage from within the recited range of 10 μg to 80 μg would not require the skill and judgment of a physician, since there is no indication that a particular duration or a fixed dose would not work for all subjects. Nevertheless, the Examiner determined that administration of the antibody based on square meter body surface area of a patient does require professional skill and judgment, citing PN 2015-01.
The Applicant successfully argued that calculation of a particular dosage based on body surface area is mere mathematical calculation that is within the skill of a technician and not a physician. The determination thus does not require professional judgment. The Patent Appeal Board also distinguished the invention in question from those of previous decisions such as Axcan and Commissioner’s Decision Re Allergan (CD 1292). The Board noted that whereas in previous decisions a physician’s skill and judgment is required to determine whether a particular dosage is appropriate for a particular patient, there is no evidence here to show that any dosage within the 10 μg to 80 μg range is inappropriate, since the description of the 594 application shows that any dosage within the range would be safe and effective and no adjustment is required. Thus, the Board is of the opinion that no skill or judgment is associated with administering any dosage as defined in the claims.
The Board’s position that the calculation of body surface area or body weight does not involve the skill and judgment of a physician is definitely a welcome clarification for patentees in the pharmaceutical industry. It is a positive step towards being able to protect innovations involving dosage regimens. Further, this case highlights that, from a patent drafting and prosecution perspective, it would be useful to provide evidence in the description as to the safety and efficacy of the entire claimed dosage range and that any selection within the range does not depend on any patient-specific factors.
In November 2020, the Patent Office published a revised Patent Examination Notice, in which they explained that the fact that at least one essential element of a claim contains a dosage range is not in itself determinative of whether a claim is unpatentable subject matter (read our article here). They confirmed that it is necessary to consider whether the exercise of professional skill and judgment of a medical professional is part of the actual invention. The 594 application provides an example of how the Patent Office implements such an analysis. However, it should be noted that the November 2020 Patent Examination Notice extends this analysis to dependent claims even in the case where the independent claim is a general use claim without a specific dosage range. Nevertheless, patent prosecution professionals and Applicants should keep in mind that dosage range claims can be allowed in Canada. As the Federal Court cautioned in a recent infringement action Janssen Inc et al. v Apotex Inc et al. (2021 FC 7) brought under s.6(1) of the Patented Medicine (Notice of Compliance) Regulations (read our article here), “the issue of method of medical treatment is not a settled one and therefore a court should be cautious in striking down claims on this basis”.3 It will be interesting to follow any future development.
