Supreme Court Expands "Laws of Nature" Exception to Patentability in Mayo v. Prometheus

This week, the U.S. Supreme Court reshaped the landscape of patent law with its long-awaited decision in Mayo Collaborative Services v. Prometheus Laboratories.  The Court ruled that certain claims of patents licensed to Prometheus, claims that related to the use of thiopurine drugs in the treatment of autoimmune diseases such as Crohn’s disease, were invalid because they did not constitute patent eligible subject matter.  In so doing, the Court held that the patent claims recited a “law of nature” – specifically, the relationship between concentrations of certain metabolites in the blood and the likelihood that a thiopurine drug dosage will be ineffective or cause harm – which is not itself patentable, and that the various steps in the method claim were insufficient to transform an unpatentable law of nature into a patent-eligible application of such a law.  The decision will be welcomed by certain patient advocate groups and medical associations, but many in the medical industry consider that the decision will discourage investment and innovation, particularly in the diagnostics field.

Mayo challenged two patents licensed to Prometheus in response to a lawsuit for patent infringement.  The U.S. District Court for the Southern District of California found that that Mayo’s diagnostic tests infringed Prometheus’s patents but granted Mayo’s motion for summary judgment on the grounds that the asserted process claims effectively claimed natural laws or natural phenomena and that such claims were not patentable.  The Federal Circuit reversed the summary judgment decision, finding that the process claims constituted patent-eligible subject matter under its “machine or transformation test.”  Mayo twice appealed the decision to the Supreme Court.  After the first appeal, the Supreme Court returned the case to the Federal Circuit for reconsideration in view of another recent Supreme Court decision in Bilski v. Kappos.  On remand, the Federal Circuit again held that the process claims constituted patent-eligible subject matter; this second appeal to the Supreme Court followed.

The Court analyzed a claim apparently representative of the claims of the two patents:

A method of optimizing therapeutic efficacy for treatment of an immune-mediated gastrointestinal disorder, comprising:

1. administering a drug providing 6-thioguanine to a subject having said … disorder; and
2. determining the level of 6-thioguanine in said subject having said … disorder, wherein the level of 6-thioguanine less than [a specified amount] indicates a need to increase the amount of said drug subsequently administered to said subject and wherein the level of 6-thioguanine greater than [another specified amount] indicates a need to decrease the amount of said drug subsequently administered to said subject.

In its analysis, the Court stated that “Prometheus’ patents set forth laws of nature – namely relationships between concentrations of certain metabolites in the blood and the likelihood that a dosage of a thiopurine drug will prove ineffective or cause harm.”  The Court then went on to consider “whether the claims do significantly more than simply describe these natural relations,” or put another way, whether “the patent claims add enough to their statements of the correlations to allow the processes they describe to qualify as patent-eligible processes that apply natural laws.”  Although the three steps in the claimed process (the administering step, the determining step, and the wherein step) were not themselves natural laws, the Court found that they were insufficient to transform the nature of the claim into patent eligible subject matter.  In particular, the Court stated that the “steps in the claimed processes (apart from the natural laws themselves) involve well-understood, routine, conventional activity previously engaged in by researchers in the field.”  The Court went on to state that if “a law of nature is not patentable, then neither is a process reciting the law of nature, unless that process has additional features that provide practical assurance that the process is more than a drafting effort designed to monopolize the law of nature itself.”

With regard to the “administering” step, the Court stated that it “simply refers to the relevant audience, namely doctors who treat patients with certain diseases with thiopurine drugs.”  With regard to the “wherein” step, the Court stated that it simply tells a doctor about the relevant natural laws, adding, at most, a suggestion that the test results be considered when making treatment decisions.  With regard to the “determining” step, the Court stated that it tells a doctor to measure the metabolite through whatever process the doctor wishes to use.  Because methods for making such determinations were well known in the art, the Court characterized this step as simply “telling doctors to engage in well-understood, routine, conventional activity previously engaged in by scientists who work in the field.”  The Court declared that such activity “is normally not sufficient to transform an unpatentable law of nature into a patent-eligible application of such a law.”  In so doing, the Court inferred that the three steps were merely “’conventional or obvious’ ’[pre]-solution activity’” or “insignificant post-solution activity.”  The Court reasoned that the “claims inform a relevant audience about certain laws of nature; any additional steps consist of well-understood, routine, conventional activity already engaged in by the scientific community; and those steps, when viewed as a whole, add nothing significant beyond the sum of their parts taken separately.”

The decision likely will call into the question the validity of many issued patent claims in the diagnostics field, including some of the claims under review in The Association of Molecular Pathology v. Myriad Genetics, as well as the patentability of pending patent applications.  For example, in many diagnostics patents, the claimed invention is premised on the discovery of a particular correlation between the presence, absence or amount of one or more biomarkers and a medical condition.  However, the claimed processes often only include steps that are well-understood, routine and conventional activities by those working in the field.  In addition, the decision may also impact the patentability of methods of conducting personalized medicine, for example, where treatment regimens for a subject are tailored based on the presence, absence or amount of one or more biomarkers that correlate with treatment efficacy.  The full reach of the decision’s impact, potentially well beyond the diagnostics field, is not yet clear.  The Court observed that “all inventions at some level embody, use, reflect, rest upon, or apply laws of nature, natural phenomena, or abstract ideas.”  That observation acknowledged that not all inventions can be unpatentable simply because they have some relationship with a law of nature.  At the same time, the observation also serves as a warning that the impact of Prometheus will not be limited to one class of invention or one field of technology.

In its concluding remarks, the Court indicated that it is up to Congress to craft finely tailored rules if, from a policy perspective, more protection for discoveries of diagnostic laws of nature are desirable.

Even in the diagnostics field many inventions will remain patent-eligible, including new and inventive methods for detecting biomarkers, and reagents and other tools for detecting biomarkers.  Similarly, in the therapeutics field the Court distinguished the unpatentable methods of Prometheus from a presumably patent-eligible “new drug or a new way of using an existing drug.”  On the other hand, the Prometheus decision will have an unavoidable impact on certain other technologies and business plans, an impact that companies and investors ignore at their peril.  For example, unless Congress intervenes, companies that routinely patented diagnostic inventions in the past may conclude that future diagnostic inventions are better kept as trade secrets.  More broadly, it is important that those in the medical industry (and beyond) take this opportunity to reevaluate their intellectual property positions, as the strategies on which companies have relied in the past may no longer be optimal in the post-Prometheus world.