On March 20, 2012, the U.S. Supreme Court unanimously held that method claims for treating gastrointestinal disorders by determining the level of certain metabolites (e.g., 6-thioguanine) in a patient after treating with a particular drug and then correlating the amount of drug and the level of metabolite did not constitute patentable subject matter under 35 U.S.C. § 101. Mayo Collaborative Servs.v. Prometheus Laboratories, Inc., 566 U.S. __ (2012). This holding reversed the Federal Circuit, which, after reconsidering in light of the Bilski decision, had reaffirmed its prior holding that the claimed process steps of (1) "administering a [thiopurine] drug" to a patient and (2) "determining the [resulting metabolite] level" involved the transformation of the human body or blood taken from it and thus satisfied the Federal Circuit's "machine or transformation test" bringing the claims into compliance with § 101. See Prometheus Labs., Inc. v. Mayo Collaborative Servs., 628 F.3d 1347, 1355–56, 1359 (Fed. Cir. 2010); 581 F.3d 1336, 1345, 1346–47 (Fed.Cir. 2009).

In rejecting the Federal Circuit's analysis, the Supreme Court focused on whether the claimed processes transformed unpatentable natural laws (correlations between certain metabolite levels and the effectiveness of treatment) into patent eligible applications of those laws by doing significantly more than simply describing the natural correlations. Mayo Slip Op. at 3, 8. Apart from the natural laws themselves, the Supreme Court found that the other steps in the claimed processes merely involved "well-understood, routine, conventional activity" previously engaged in by researchers in the field. Id. at 10–11. The other "administering" and "determining" steps were required to apply the laws in question and their effect was "simply to tell doctors to apply the law somehow when treating their patients." Id. at 13. Thus, the Supreme Court concluded that the claims did not do significantly more than simply describe the natural correlations and therefore were not patent-eligible subject matter. Id. at 8, 11, 18–19.

The Supreme Court considered and expressly rejected the government's argument that "virtually any step beyond a statement of a law of nature itself should transform an unpatentable law of nature into a potentially patentable application sufficient to satisfy § 101's demands," stating that the government's approach would make the "law of nature" exception to § 101 patentability "a dead letter." Mayo Slip Op. at 20–21. The Supreme Court thus declined the government's invitation to substitute §§ 102, 103, and 112 inquiries for the § 101 analysis. Id. at 22. While acknowledging the conflicting views of the amici on this issue, the Supreme Court pointed out that it is the role of Congress to craft more narrowly tailored rules where necessary and that the Supreme Court did not need to determine whether, from a policy perspective, increased protection for discoveries of diagnostic laws of nature is desirable. Id. at 23–24.

What This Means for You

Mere discovery of a law of nature and crafty claim drafting does not create patent-eligible subject matter under 35 U.S.C. § 101. To pass the § 101 test, a claimed process involving a law of nature must include steps that apply that law in new ways. If the additional steps merely require routine actions that prior researchers would undertake to apply the law, they will not be sufficient to make the claimed process eligible for patent protection.

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