Patentability of laws of nature in the United States: the Mayo case


On March 20th, 2012, the Supreme Court of the United States issued a landmark decision regarding patentability of laws of nature.

Pursuant to Section 101 of the US patent law (35 USC 101), only the processes, machines, manufactures or compositions of matter are patentable inventions. This definition has been completed by the Case law which specified on several occasions which inventions were not included in the list of Section 101. For example, the Supreme Court indicated in the decision Gottschalk v. Benson (1972) that the laws of nature were not patentable because they are tools at the basis of scientific and technical work. In the decision Diamond v. Chakrabarty (1980), the Supreme Court reaffirmed this principle by specifying that Einstein could not patent his famous law E=mc2, nor Newton his gravitation law, because such findings are manifestations of  nature, free to all men, and reserved exclusively to none.

In the Mayo Collaborative Services v. Prometheus Laboratories, Inc. (Mayo v. Prometheus) case, claim 1 of the contested patent related to a method of optimizing therapeutic efficacy of an immune-mediated gastrointestinal disorder, comprising two steps:

(a) administering a medicament (in this case a thiopurine);

(b) determining the level of a definite metabolite (6-thioguanine) of the medicament,

wherein a level under a threshold value indicate the need for increasing the dose of said drug, and

wherein a level above a threshold value indicate the need for reducing the dose of said drug.

The Supreme Court had to determine whether this method was simply enunciating a law of nature, thereby unpatentable, or consisted in a patentable application of this law.

Accordingly, the Cour examined the various steps of the claimed method and first concluded that the « wherein » clause establishing a relationship between a threshold value of the metabolite level and the need for changing the dose of the medicament was merely enunciating a law of nature.

Regarding the administration step, it only defines the target public of the method: physicians treating their patient with a thiopurine. Finally, the step of determining the metabolite level merely invites the physicians to engage in « well understood, routine, conventional activity ».

To summarize, the claim only recommends to physicians to collect data from which they can take a decision under consideration of the existing correlation between the data. This is not sufficient for rendering an unpatentable law of nature into a patentable application of this law.

In this decision, the Supreme Court thus affirms that the combination of a natural process and of known elements does not form a patentable application of the natural process. In particular, the Cour insists on the importance to not let allow the appropriation of a law of nature by a right of intellectual property which would forbid its use by other parties, thus reaffirming the principles enunciated in the Gottschalk v. Benson and Diamond v. Chakrabarty decisions.

The unanimous decision of the Supreme Court (9 pro, 0 con) bears important consequences on the patentability of diagnostic methods in the United States. The validity of a number of granted patents could be put in question, while a number of pending applications could be rejected by the USPTO based on the Mayo decision.

In fact, one of the first consequences of this decision was quick to come: the Supreme Court requested the Appeal Court for the Federal Circuit to review its decision in the famous Myriad Genetics case, in view of the Mayo decision. This review of the Myriad Genetics case shows that the Mayo decision could also put in question the patentability of isolated genes. In the first decision issued in the Myriad case, the Appeal Court had considered that an isolated DNA sequence formed a different molecule than the same sequence when it is part of the human genome. The Court had thereby acknowledged the patentability of an isolated gene. However, all things considered, an isolated gene is nothing more than the combination of a natural product (DNA) and a known process (DNA isolation). We shall see in the future if the Appeal Court will choose, by analogy, to apply to a product claim the reasoning of the Mayo decision, which relates to a method claim.