On June 10, 2013, the Canadian Intellectual Property Office (CIPO)1 issued a guidance document for patent examiners (the “Notice”) on examining claims to medical uses. The Notice applies to medical use claims “per se”, regardless of form, but the emphasis of the guidance is the examination of claims that recite dosage regimens or dosage ranges.  Unfortunately, the notice does not make matters much clearer and continues CIPO’s practice of deviating from the Supreme Court precedent on purposive construction.

The Notice reaffirms that medical use claims (as opposed to medical method claims) are generally permitted, but directs that “inventions preventing physicians from exercising their skill and judgment in using a known compound for an established purpose effectively cover a method of medical treatment”. The Notice offers guidance to examiners on identifying such cases. The assessment of whether a claim is directed to patentable subject matter is to be based on “the essential elements of the claim as determined by a purposive construction”. A purposive construction requires the identification of the problem to be solved and the solution disclosed based on a consideration of the specification as a whole. The Notice offers specific guidance to examiners on identifying the problem and solution. Of note, the Notice provides that if the applicant is explicit as to the nature of the problem, “examination should generally proceed accordingly unless doing so would be unreasonable on an informed reading of the application in light of the common general knowledge.”

A distinction is drawn between an essential element that only instructs a medical professional “how” to treat a patient (not allowable) versus one directed to “what” is used to treat a patient (allowable). Elements that purportedly point to limitations on a physician’s skill or judgement are identified as details of a dosing schedule, a range of potential dosages and narrowing treatment to a patient sub-population or administration site.