Court ruling applies law of nature; impacts patents directed to personalized medicine.

In Mayo Collaborative Services v. Prometheus Laboratories, Inc., U.S., No. 10-1150, an opinion authored by Justice Stephen Breyer, the U.S. Supreme Court unanimously ruled that method claims directed to the personalized use of medicines are not patentable subject matter under 35 U.S.C. Section 101. The claims at issue, which were directed to adjusting the administered dose of a drug after determining the levels of metabolites of that drug in a patient, were deemed to be effectively a law of nature and thus represent nonpatentable subject matter.

Prometheus originally sued Mayo on the basis that Mayo's diagnostic kit allegedly infringed Prometheus's exclusively licensed patents directed to a method of adjusting doses of a drug providing a thiopurine metabolite based on the detected levels of the metabolite in a patient (U.S. Patents 6,355,623 and 6,680,302). The method claims involved the three steps of (1) administering a drug providing a thiopurine metabolite to a patient, (2) determining the level of the thiopurine metabolite in the patient, and (3) a wherein step informing the doctor that metabolite concentrations above or below the claim thresholds "indicate a need" to decrease or increase (respectively) the drug dosage. The trial court determined that the claims relied on a law of nature. The U.S. Court of Appeals for the Federal Circuit reversed, deciding that the treatment satisfied the "machine or transformation" test. The Supreme Court remanded the case in view of the decision in Bilski v. Kappos, 130 S. Ct. 3218 (2010), that the "machine or transformation" test is not the sole or definitive test to determine if a process is patent eligible. The Federal Circuit then reaffirmed its original decision.

The Court first ruled that Prometheus's claims involved a law of nature in the relationships between concentrations of certain metabolites in the blood and the likelihood that a dosage will be ineffective or toxic. The Court then stated that the issue was whether the claims add enough to the correlations described to qualify as a patent-eligible process that applies natural laws. Precedential cases, such as Diamond v. Diehr, 450 U.S. 1981 (1981), and Parker v. Flook, 437 U.S. 584 (1978), had qualified that application of a law of nature or a mathematical formula in a novel and useful structure or process may be patentable.

The Supreme Court distinguished Prometheus's claims from the precedential cases on the basis that Prometheus merely used what was already known and easily understood to apply a law of nature. The Court found that administering the drug only established the relevant audience and that the "wherein" clause recited the law of nature. The Court ruled that determining the metabolite levels was a well-understood conventional activity and that this step could potentially be performed without transforming the patient's blood. In examining the claimed process as a whole, the Court found that the step of determining the metabolite levels added nothing significant beyond the sum of the parts taken separately. The Court further noted that while the laws of nature at issue were relatively narrow, the claims still tie up the use of the law of nature and foreclose the development of a more refined treatment. The Court also stated that application of a natural law to a known structure may still be patentable, but the application must be significant and include additional inventive concepts separate from the natural law without being so broad that it preempts the use of the law.

Clients holding patents directed to personalized treatment regimens are encouraged to assess the scope of such claims in light of this decision.