Patent Claims to Medical Diagnostic Methods: Practice Notice Updates

The Canadian Intellectual Property Office (CIPO) has released a Practice Notice on the examination of patent claims related to medical diagnostics methods.¹ The Notice sets out the tests for an examiner to apply in determining the subject matter eligibility of a diagnostic claim that extracts diagnostic meaning from data, with the suggestion that a level of physicality to data acquisition step(s) will be an important factor for consideration by the examiner.

Problem-Solution Test Continues to Apply

Following on its 2013 practice guidance regarding purposive construction, the CIPO continues to advocate that examiners use the "problem-solution" method of claim construction.² This method involves identifying both the problem the inventors set out to solve as guided by the patent application’s description and the common general knowledge in the art, and the proposed solution, also guided by the description. Having identified the solution, the Practice Notice states that the examiner must then determine the element or set of elements essential to that solution.

Physicality of Data Acquisition vs. Data Analysis

The Practice Notice distinguishes between a "data acquisition problem" and a "data analysis problem": the former is generally characterized by a description directed to identifying, quantifying or acquiring data on a chemical substance or biomarker (an "analyte"); and the latter is generally characterized by a description directed to correlation(s) between a condition and an analyte. According to the CIPO, a problem identified as a "data analysis problem" is unlikely to include any steps to acquire the data, since the way in which the data is acquired does not affect the nature of the solution.

The Practice Notice suggests that "data analysis" solutions will generally be viewed as unpatentable, where the identified solution is only provided by an element or set of elements associated with the analysis or significance of acquired data. The CIPO views that the recitation of only data analysis elements that are disembodied (e.g., mental process, lacking physicality or having no physical application) is insufficient to meet the subject matter eligibility criteria of the Patent Act.

In contrast, the Practice Notice indicates that a claim having a physical step of data acquisition as an essential element will likely be found subject-matter eligible. While the Notice does not explicitly address the situation of an essential non-physical step of data acquisition, the following examples given by the CIPO as to elements expected to be characterized as "data acquisition" suggest that physicality will be an important factor to subject matter eligibility:

• detecting protein X in a subject sample;
• measuring the concentration of substrate X;
• determining the expression levels of genes A, B and C;
• contacting a urine sample with antibody A and determining the optical density; and
• incubating a sample with a nucleic acid probe consisting of SEQ ID NO: 1 and detecting hybridization between the probe and target sequence A.

This Notice brings some clarity to the subject matter eligibility of medical diagnostic method claims. The CIPO has put these Notice guidelines into effect, and we expect to begin to see their impact on the examination of medical diagnostic method claims in Canada soon.

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¹ PN 2015-02: www.ic.gc.ca/eic/site/cipointernet-internetopic.nsf.

² PN 2013-02: www.ic.gc.ca/eic/site/cipointernet-internetopic.nsf.