What to use vs. how to treat: Important distinction for patentability of health care inventions

Canada has a long-standing prohibition against granting patents for inventions that are “methods of medical treatment.” A decision of the Patent Appeal Board (PAB) issued earlier this year provides some clarity on when an invention will be considered a method of medical treatment and when it will be considered patentable subject matter.

Patentable subject matter in Canada

Under section 2 of the Canadian Patent Act, an invention is defined as “any new and useful art, process, machine, manufacture or composition of matter, or any new and useful improvement in any art, process, machine, manufacture or composition of matter.” A “method” claim that describes a series of steps to obtain a desired result will generally fall within the category of “art.”

However, case law in Canada has held that methods of medical treatment and surgical methods do not fall within the definition of invention under section 2. The basis for this exclusion is that these methods are not related to trade, industry or commerce, but instead are related to a professional’s skill and judgment. For policy reasons, the courts were likely wary of permitting surgical methods to be patented as this could hinder a physician’s (and other professionals) ability to practise their profession without fear of patent infringement. So, where a method provides a therapeutic benefit to a human or animal patient, it will not be permitted subject matter in Canada.

From a practical perspective, claims directed to methods can often be drafted in a way to avoid characterizing the invention as a method of medical treatment. For example, a claim such as “A method of treating cancer by administering drug X to patient,” can be recast as “Use of drug X to treat cancer.”

The latter will be deemed acceptable subject matter. Methods to surgical interventions can be more difficult to convert, as the patent office will typically reject any claim having an active treatment step.

The Canadian patent office makes a distinction between methods related to the treatment of “ailments or pathological” conditions, which are not patentable subject matter, and “natural conditions” which can be subject to patent protection. The patent office gives the examples of ageing, pregnancy, baldness and wrinkles as non-pathological, natural occurring conditions.

Commissioner’s Decision No. 1491

Commissioner’s Decision No. 1491, related to a patent ultimately issued on Oct. 8, 2019, provides some helpful guidance on permissible subject matter claims.

CooperVision International Holding Company had filed Canadian patent application 2,760,920 directed to “Use of accommodative error measurements in providing ophthalmic lenses.” The application claimed methods of providing and using lenses sequentially to reduce or prevent the progression of myopia (i.e., nearsightedness), an eye condition that is known to get worse as a person ages.

The patent office examiner reviewing the application had originally rejected the claims as methods of medical treatment and therefore non-patentable subject matter. This decision was appealed to the PAB, which held that the claims should be allowed.

The PAB based this decision on the fact that myopia is a natural human condition as assessed by ophthalmologists, being experts in the relevant field. These experts would not consider myopia a pathological disease. Therefore, the PAB determined that the claims could not be considered methods of medical treatment.

The PAB went on to provide further guidance on assessment of claims for instances where the invention is directed to a pathological condition. The PAB indicated that a distinction should be made between claims that are directed only to “how” to treat a patient, as opposed to claims directed to inventions for “what” to use to treat a patient.

If the essential elements of a claim give instruction to health care professionals on “what” to use to treat a patient, then the claims are not directed to a method of medical treatment. However, if the essential elements are directed to “how” to treat a patient, further consideration of the subject matter is needed. An examiner must assess whether the performance of the claim would interfere with the professional skill and judgment of a health care professional. If the answer is yes, the claim will be rejected as an unpatentable method of medical treatment. Thus, claims that are directed to “how” to treat could be statutory subject matter if such claims to not restrict the ability of a professional to exercise their skill and judgment.

Practice point

While claims can often be redrafted to convert methods of treatment to use claims in Canadian patent applications, Decision No. 1491 is helpful to applicants that are encountering rejections in prosecution on the basis of subject matter. If a condition can be characterized as relating to the natural ageing process, the claim should not be deemed to be a method of medical treatment.

Furthermore, Decision No. 1491 instructs examiners to assess whether (i) a claim is directed to “what” to use vs. “how” to treat, and (ii) for “how” to treat claims, only those that impede professional skill and judgment should be considered non-statutory. This decision can be asserted where the applicant’s invention is in alignment with these principles.

This article was originally published by The Lawyer’s Daily part of the LexisNexis Canada Group Inc.