As life science and biotech companies discover and try to protect new medical uses of pharmaceutical compounds, patents covering these uses are crucial.  Earlier this year, the Canadian Intellectual Property Office ("CIPO") released practice guidelines for the examination of patent applications directed to these "medical uses"[1].  In the words of CIPO, "…the examination of medical use claims, including dosage regimens and dosage ranges, requires specific guidance in order to ensure efficient, predictable and reproducible examination of applications."

To provide this efficiency, predictablity and reproducibility, CIPO has now outlined what factors are to be considered in examining these applications.  This practice note is designed to provide some suggested strategies to help patentees obtain Canadian patent protection for medical uses.  In order to comply with the new CIPO guidelines, applicants should focus on "what" to use for treatment rather than "how" to treat.


It has been the law in Canada since the early 1970's that methods of medical treatment and surgery are not patentable.  CIPO has, however, allowed "use" claims provided that they do not encompass an active treatment or surgical step and many applicants have used these claims to get around the prohibition on medical treatments.  In more recent years, CIPO has been restricting the scope of such use claims, including claims directed to dosing/dosage regimes.

Canadian patent examiners are to assess patentability using a "purposive construction" approach.[2]  To perform a purposive construction, an examiner identifies the problem the inventors set out to address and the solution disclosed.  In identifying the problem faced by the inventors, the examiner will consider what the inventors state about the background of the invention, their objectives of the invention, any specific problems, needs, limitations or disadvantages known in the art or discovered by the inventors, etc.  The solution is the element or set of elements essential to the successful resolution of the problem.

The Solution Should Focus on the "What" not the "How"

A "purposive construction" assessment will be done for medical use claims as well.  Where the solution is a new compound, a new use of a compound or an improvement thereto (the "what"), the patent application will be considered proper under the new CIPO guidelines.  Where a dosage regimen or a dosage range is essential (the "how"), CIPO is of the view that the claim covers a method of medical treatment, and thus, is not patentable.  Where the emphasis of the application is not on "what" to use but instead relates to "how" to administer or refine a treatment, the solution as embodied by the essential elements of the claim will be refused as not being patentable subject matter.  The reasoning behind this is that any limitation of a physician's professional skill or judgment (i.e. how to treat patients) should not be permitted.

If applicants can focus, therefore, on the "what" rather than the "how", they stand a better chance of getting patent protection for their medical use directed patent.