On March 20, 2012, the Supreme Court handed down its opinion in Mayo Collaborative Services v. Prometheus Labs., Inc., No. 10-1150.  In this case, the Court considered the validity of two patents belonging to Prometheus with claims directed towards the use of thiopurine drugs for the treatment of autoimmune diseases.  In general, the claims recited steps including (i) administering the drug to a patient; (ii) determining the number of metabolites in a patient; and (iii) adjusting the subsequent dose of the drug based upon the number of metabolites that were present in the patient.  The main issue considered by the Supreme Court was whether the subject patents were invalid under 35 U.S.C. § 101 for failing to claim patentable subject matter (as held by the district court) or whether the patents claims were valid under the machine-or-transformation test (as held by the Federal Circuit).

In its opinion, the Supreme Court reversed the Federal Circuit’s decision and held that the patents were invalid under Section 101.  Initially, the Court characterized the claims as being directed to a law of nature, namely, the relationship between concentrations of metabolites in the blood and the efficacy of a drug.  Further, the Court explained that the claims only recite “well-understood, routine, conventional activity already engaged in by the scientific community . . . .”  Slip. Op. at 11 (U.S. March 20, 2012).  The Court then concluded that “the [claimed] steps are not sufficient to transform unpatentable natural correlations into patentable application of those regularities.”  Slip. Op. at 11 (U.S. March 20, 2012).

Members of the patent bar have raised several concerns with this latest Supreme Court opinion that impacts patent law:

• The Court’s opinion will likely encourage the use of Section 101, as opposed to other conditions for patentability, in evaluating the validity of patent claims.  The concern with such a trend is that there was a traditionally low burden for meeting subject matter eligibility under Section 101 for non-business method patents.  Now, post-Prometheus, courts may argue that broad patent claims are not directed to patentable subject matter, as opposed to invalidating such claims on the basis of prior art disclosures.
• In reaching its decision, the Court failed to outline a test to determine whether claims based upon a law of nature are directed to patentable subject matter.  After explaining why Prometheus’ patents are invalid, the Court commented that “[w]e need not, and do not, now decide whether were the steps at issue here less conventional, these features of the claims would prove sufficient to invalidate them.”  Slip. Op. at 18 (U.S. March 20, 2012).  In other words, the Court hints that a patent claim reciting a combination of a law of nature with unconventional steps may be valid, but it does not explain what would be deemed unconventional.
• The Court’s decision adds confusion to its 2010 decision in Bilski v. Kappos, No. 08-964.  In Bilski, the Court commented that although it is not the only test for determining whether a claimed method is patentable subject matter, “the machine-or-transformation test is a useful and important clue, an investigative tool, for determining whether some claimed inventions are processes under § 101.”  Slip. Op. at 8 (U.S. June 28, 2010).  However, in Prometheus, the Court holds that some claimed methods may pass the machine-or-transformation test, but yet still fail the requirements of Section 101.

In light of the Prometheus decision, there is a new importance on meeting the requirements of Section 101, especially for patents directed to diagnostic and therapeutic processes.  While the Court’s decision creates more questions concerning what types of claims would meet subject matter eligibility, it appears that claims that could be interpreted as reciting a law of nature should drafted to include unconventional steps or other novel properties in order to meet the requirements of Section 101.