Canada: Medical Diagnostic Claims and "Bilski"

In the long awaited decision in Bilski v. Kappos,1 the U.S. Supreme Court has concluded that the machine-or-transformation ("MOT") test is not the sole arbiter of patentable subject matter for "processes" under section 101 of the U.S. Patent Act.2 The decision is expected to have far reaching effects for business methods and other processes, including medical diagnostics.

The court's majority stated that there are four broad categories for patentable subject matter, namely "processes, machines, manufactures, and compositions of matter". The court affirmed the existence of three specific exemptions to 101's broadest principles: laws of nature, physical phenomena, and abstract ideas. The court refused to accept the MOT test, adopted by the Federal Circuit in its Bilski ruling, as the sole test for determining patent eligible subject matter for processes. The Court also refused to establish a different bright-line test. The MOT test is not dead, however. The decision indicated that the "[MOT] test is a useful and important clue, an investigating tool, for determining whether some claimed subject matter are processes".

Calling into question the MOT test is expected to be far reaching, extending beyond the evaluation of business methods, the subject matter at the heart of Bilski's application. Though not strictly a part of the holding in Bilski, some of the majority agreed3 that the MOT test would create uncertainty as to the patentability in several new areas of technology including advanced diagnostic medicine techniques. This reference to diagnostic techniques may be directed to several recent decisions using the MOT test including, Classen Immunotherapies, Inc v. Biogen IDEC et al.4 and Mayo Collaborative Svcs et al. v. Prometheus Labs.5 Importantly, both cases were remanded the day after Bilski to the Federal Circuit for further consideration.

The claims in Classen6 are directed to methods of selecting vaccine regimes and were found to unpatentable by the District Court as "an attempt to patent unpatentable natural phenomenon". This conclusion was affirmed by the Federal Circuit since the methods "are neither 'tied to a particular machine or apparatus', nor do they 'transform[] a particular article into a different state or thing' Bilski".7 The claim in Classen is similar in format to the claim in Laboratory Corp. v. Metabolite Labs. Inc.8 involving a diagnostic method for identifying a vitamin deficiency based on increased levels of homocysteine in blood.9 However, the diagnostic claim in Metabolite, as affirmed by the Supreme Court, earlier was found patentable and determined to not constitute a law of nature.

The format of the claims in Classen and Metabolite, and many diagnostic claims including genetic testing10 (e.g. Association for Molecular Pathology, et al. v. USPTO, et al.11), are similar and involve identifying a biological state,12 using a diagnostic step that identifies a some type of biomarker,13 and correlating the biomarker with the biological state.14 In Myriad, the District court found that a diagnostic method that involves comparing an isolated DNA with a naturally occurring DNA does not satisfy the MOT test, and that the process of extracting DNA in itself is not transformative, but rather a data-gathering step. That court further concluded that an isolated gene sequence is the same as DNA found in the body. While the Myriad decision has recently been appealed, future developments in Classen, and Myriad will be of great significance to determine the application of the MOT test to claims involving diagnostic methods.

In Prometheus, the opposite conclusion to that of Classen was reached. The Federal Circuit applied the MOT test to consider whether claims15 directed to calibrating an appropriate dosage of an autoimmune medication, was patent eligible subject matter under 35 U.S.C. §101. They stated that the "transformation is of the human body following administration of a drug and the various chemical and physical changes of the drugs metabolites that enable their concentrations to be determined". In this method, the drug (a thiopurine) "necessarily under goes a transformation" within the body after administration, and "a process for a chemical or physical transformation of physical objects or substances is patent-eligible subject matter" (emphasis in the original text).

One of the challenges raised in Prometheus was that transformation within the body is a natural processes because "quite literally every transformation of physical matter can be described as occurring according to natural processes and natural law". Interestingly, even though the claims in Prometheus were found to pass the MOT test, this case was also remanded following Bilski, likely as a result of the conclusion that the MOT test is not the sole test.

Applicants and licensees will watch with interest the upcoming decisions in the remanded cases. In the meantime, incorporating diagnostic claims in an application is still an appropriate strategy while the patentablility of this type of claim remains unclear. Where possible, other claim types ought to be included, such as kit claims, or claims that tie the diagnostic process to an apparatus.


1. 08-964, U.S. Supreme Court; "Bilski"

2. 35 U.S.C. §101

3. Slip op. Part II-B-2. pp.8-10

4. 08-1509, U.S. Federal Circuit; "Classen"

5. 09-490; U.S. Federal Circuit; "Prometheus"

6. US 5,723,283; Claim 1 reads:

A method of determining whether an immunization schedule affects the incidence or severity of a chronic immune-mediated disorder in a treatment group of mammals, relative to a control group of mammals, which comprises immunizing mammals in the treatment group of mammals with one or more doses of one or more immunogens, according to said immunization schedule, and comparing the incidence, prevalence, frequency or severity of said chronic immune-mediated disorder or the level of a marker of such a disorder, in the treatment group, with that in the control group.

7. 545 954

8. 04-607; U.S. Supreme Court; "Metabolite"

9. US 4,940,658. Claim 13 reads:

A method for detecting a deficiency of cobalamin or folate in warm-blooded animals comprising the steps of: assaying a body fluid for an elevated level of total homocysteine; and correlating an elevated level of total homocysteine in said body fluid with a deficiency of cobalamin or folate.

10. US 5,747,282; US 5,837,492; US 5,693,473; US 5,709,999, US 5,710,001; US 5,753,441; US 6,033,857

11. 09- CIV 4515; U.S. District Court, "Myriad"

12. a vitamin deficiency (Metabolite), or a chronic immune-related disorder (Classen)

13. assaying a bodily fluid to detect elevated homocysteine levels (Metabolite), or immunizing mammals with one or more doses of one or more immunogens (Classen)

14. correlating elevated homocysteine with the vitamin deficiency (Metabolite), or comparing the incidence, prevalence, frequency or severity of chronic immunemediated disorders in mammals immunized according to the immunization schedule (Classen).

15. Prometheus was the sole licensee of US 6,355,623 and US 6,680,302; Claim 1 of the '623 patent was cited in the Federal Circuit opinion as being representative: A method of optimizing therapeutic efficacy for treatment of an immune-mediated gastrointestinal disorder, comprising: (a) administering a drug providing 6-thioguanine to a subject having said immune-mediated gastrointestinal disorder; and (b) determining the level of 6-thioguanine in said subject having said immune-mediated gastrointestinal disorder, wherein the level of 6-thioguanine less than about 230 pmol per 8x108 red blood cells indicates a need to increase the amount of said drug subsequently administered to said subject and wherein the level of 6-thioguanine greater than about 400 pmol per 8x108 red blood cells indicates a need to decrease the amount of said drug subsequently administered to said subject.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.

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