Mayo Collaborative Services v. Prometheus Laboratories, Inc., 132 S. Ct. 1289 (2012) (Breyer, J. for unanimous Court).  For the slip opinion, click here: Mayo03202012.USSC

SUMMARY:  CLAIM TO “LAW OF NATURE”; PROCESS STEPS NOT SUFFICIENT TO TRANSFORM CLAIM INTO A PATENT-ELIGIBLE APPLICATION OF A LAW OF NATURE; WELL-UNDERSTOOD, ROUTINE, CONVENTIONAL STEPS PREVIOUSLY USED BY RESEARCHERS IN FIELD; CLAIM TYING UP USE OF UNDERLYING NATURAL LAW AND INHIBITING ITS USE FOR FURTHER DISCOVERY. A patent concerned thiopurine drugs, which are used to treat immune-mediated gastrointestinal disorders. When a thiopurine drug is administered to a patient with the disorder, the patient develops metabolites, including G-TG and 6-MMP. The patent reports the named inventors’ discovery of precise correlations between the level of the metabolites in the patient’s blood and the drug’s efficacy and toxicity. The correlations are useful to physicians for adjusting the drug dosage up or down for a particular patient. The claim at issue recites two steps: (1) administering the drug to a patient with an immune-mediated gastrointestinal disorder and (2) determining the level of the 6-TG metabolite, together with two “wherein” clauses, which recite that a concentration below one specified level (230 pmol) “indicate[s] a need to increase” drug dosage and a concentration above another level (400 pmol) indicates a need to decrease the dosage. A district court held the claim invalid as a “law of nature. The Federal Circuit reversed. HELD: the Federal Circuit erred. The claim is invalid as drawn to a “law of nature,” that is, the relationship between metabolite concentration in blood and thiopurine drug efficacy and toxicity. The recited steps of administering the drug, determining the metabolite level together with the “wherein” indications of a need for dosage adjustment, do not transform the claim into a patent-eligible application of a law of nature because (1) “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,” and (2) “upholding the patents would risk disproportionately tying up the use of the underlying natural laws, inhibiting their use in the making of further discoveries.”

COMMENTARY.  For a critical commentary on Mayo, see below. Read CPLRG™ 0079