Mayo Collaborative Servs. v. Prometheus Labs., Inc.

Case Name: Mayo Collaborative Servs. v. Prometheus Labs., Inc., Civ. No. 10-1150, 2012 U.S. LEXIS 2316 (March 20, 2012) (Breyer, J. delivered unanimous opinion of the Court), on cert. from Prometheus Labs., Inc. v. Mayo Collaborative Servs. & Mayo Clinic Rochester, 628 F.3d 1347, 2010 U.S. App. LEXIS 25956 (Fed. Cir., 2010). (Claims directed to methods for determining the toxicity of thiopurine drugs in the treatment of autoimmune diseases were held invalid under 35 U.S.C. § 101 because they preempted laws of nature, namely, correlations between thiopurine metabolite levels and efficacy and toxicity.).

Drug Product and Patent(s)-in-Suit: Diagnostic Tests for Thiopurine Drugs; U.S. Pat. Nos. 6,355,623 and 6,680,302.

Nature of the Case and Issue(s) Presented:  The issue here concerns whether the asserted claims of U.S. Pat. Nos. 6,355,623 and 6,680,302 (the '623 and '302 patents, respectively) that allegedly covered diagnostic tests sold by exclusive licensee Prometheus Laboratories, Inc. ("Prometheus") were directed towards patent-eligible subject matter.  Petitioners Mayo Collaborative Services and Mayo Clinic Rochester ("Mayo") argued that the claims of the '623 and '302 patents were directed toward unpatentable laws of nature. 

In 2004, Mayo announced its intention to market and sell its own, somewhat different version of Prometheus' diagnostic tests.  Prometheus filed suit against Mayo in the United States District Court for the Southern District of California alleging infringement of the claims of the '623 and '302 patents.  In 2008, the district court found that Mayo's diagnostic test infringed the claims of the '623 and '302, but granted summary judgment in favor of Mayo, finding that the '623 and '302 patents were invalid under § 101.  Prometheus appealed the case to the United States Court of Appeals for the Federal Circuit, which reversed the district court's finding of invalidity as to both patents.  Mayo then filed a petition for certiorari to the Supreme Court.  In 2010, the United States Supreme Court vacated and remanded the case to the Federal Circuit for further consideration in light of its holding in Bilski, which clarified that the "machine or transformation test" was not a definitive test of subject matter eligibility, but instead represented one clue to be used in the overall analysis.  The Federal Circuit applied the Supreme Court's holding in Bilski and held that the '623 and '302 patents were valid, and were directed toward patentable-eligible subject matter.  Mayo again filed a petition for certiorari to the Supreme Court, which was granted.        

Why Prometheus Prevailed:  In a unanimous decision authored by Justice Breyer, the United States Supreme Court determined that the claims of the '623 and '302 patents were not directed toward patent-eligible subject matter.  The diagnostic test at issue was designed to determine the appropriate dosage of thiopurine drugs to administer to a patient by monitoring the level of metabolites of the drug present in the bloodstream after administering the drug.  A high concentration of metabolites in the bloodstream had the potential to trigger dangerous side effects, while a low blood concentration indicated a clinically ineffective dose.  The patent claims covering the diagnostic test involved a sequential, three step process involving an "administering" step, which identified a group of people interested in the correlations, a "wherein" step, in which the party administering the diagnostic test was informed of the relevant natural laws regarding appropriate metabolite concentrations, and a "determining" step, which instructed the party administering the thiopurine drug to measure a patient's metabolite levels through whatever process the administering party deemed acceptable.

First, the Court noted that the relationship between the administration of a drug and the metabolites present in the bloodstream after administration was clearly a non-patentable statement of a natural phenomenon that existed apart from any human action.  The Court's inquiry then, was whether the claims of the asserted patents did anything more than describe this relationship.  The Court noted that an otherwise unpatentable claim could not be made subject- matter eligible by simply limiting the group of individuals who should be informed of the law.  As an example, the Court indicated that Albert Einstein could not patent the law he discovered correlating energy and matter (E=mc²) by simply identifying  linear accelerator operators and instructing them to apply this law.  In this case, the "administering" step did nothing more than identify a specific group (doctors), while the "determining" step instructed them to determine metabolite concentrations in the blood through the use of an accepted test.  The Court noted that the specification of the '623 patent stated that such tests for determining metabolite concentrations in the blood were well known in the art before the filing date of the '623 patent.  The Court concluded that the claims inform a relevant audience about certain laws of nature; any additional steps consist of well-understood, routine conventional activity already engaged in by the scientific community; and those steps, when viewed as a whole, add nothing significant beyond the sum of their parts taken separately.

The Court then engaged in a detailed comparison of the claims at issue with those considered by the Supreme Court in the Diehr and Flook cases.  In Diehr, the patented process under consideration involved the application of the Arrhenius equation to a process used to determine the optimum time to open a mold used to make rubber.  The Court ultimately found that the process claimed in Diehr did represent patentable subject matter because it did more than simply recite and apply the Arrhenius equation.  In addition to the Arrhenius equation, the process at issue involved a variety of other steps that included monitoring the temperature of the mold, constantly recalculating cure times through the use of a computer and automatically opening the press at the optimal time.  Those additional steps, the court found, transformed the process into an inventive application of the formula.  Flook, on the other hand, involved an attempt by the patentee to claim a process that the Court found unpatentable.  The process at issue involved measurement of a variable, the application of an algorithm to calculate alarm limits based on the variable measurements, and adjustment of the system to reflect new alarm limit values.  The Court found that the algorithm employed was nothing more than a recitation of a law of nature, and that monitoring variables and re-computing alarm limits based on variable readings were conventional and obvious concepts that did not transform an unpatentable principle into a patentable process.  After considering the claims at issue in Diehr and Flook, the Court determined that the claims of the '623 and '302 were weaker than Diehr, and no stronger than the unpatentable claims asserted in the Flook case.  The Court hinted that in order to claim patentable subject matter, in addition to reciting a law of nature, a process should also claim several unconventional steps that confine the claims to a particular, useful application of the principle.  The Court cautioned that upholding patents that simply appended conventional steps, specified at a high level of generality, to laws of nature and natural phenomena would inhibit further discovery by improperly tying up the future use of laws of nature.

Last, the Court considered Prometheus's argument that the asserted claims constituted patentable subject matter because they "transformed" the patient, as understood by the "machine-or- transformation test" described in Bilski.  The Court rejected this argument based on the fact that a diagnostic test could be developed in the future for measuring metabolites that did not involve any type of transformation of the patient's blood.  Regardless, the Court held that the "machine- or-transformation test" did not trump the "law of nature" exclusion.  The Court also rejected arguments set forth in the United States' amicus curiae brief, where it asserted that virtually any step beyond a mere recitation of a natural law should transform a claim into a patentable application sufficient to satisfy § 101's eligibility requirements.  The Government argued that after making this minimal showing, other provisions of United States patent law, such as anticipation, obviousness, enablement and the written description requirement would eliminate unpatentable subject matter.  The Supreme Court rejected this argument, finding that such an approach would essentially render § 101 null and void, and would also depart from well-established precedent.