Skip Page Banner  
Skip Navigation

Supreme Court Again Considers Patentability of Medical Diagnostic Claims

Wednesday, July 6, 2011

Naresh Sritharan | Bloomberg Law For the second time, the U.S. Supreme Court has granted certiorari in Mayo Collaborative Services v. Prometheus Laboratories, Inc.1 to review the patentability of methods for optimizing the dosage of a therapeutic drug. The Court's decision will likely impact the burgeoning field of personalized medicine, which seeks to customize healthcare by tailoring decisions and practices to the individual patient. Mayo Collaborative Services, the petitioner, has argued that the patents at issue, which have twice been found not invalid by the Federal Circuit, claim ineligible subject matter. Prometheus maintains that its patents represent innovation and has asserted that Mayo's claims "ring particularly hollow."2 This article will review the case's lengthy proceedings and consider the future of medical diagnostic patent claims.

Defining Patentable Subject Matter

Under the U.S. Patent Act, "any new and useful process, machine, manufacture, or composition of matter, or any new and useful improvement thereof" is eligible for patent protection.3 Although the Supreme Court has previously interpreted the Act to include "anything under the sun that is made by man,"4 the Court specifically excluded "manifestations of . . . nature, free to all men and reserved exclusively to none."5 Moreover, an unpatentable principle cannot be transformed into a "patentable process" merely through the addition of conventional method steps.6 The Court has noted, however, that a patent is not invalid "simply because it contains a law of nature."7 Rather, the patentability analysis centers on whether "the claim 'wholly pre-empts' all uses of the natural phenomenon . . . such that the 'practical effect is a patent on the [phenomenon] itself."8

District Court Finds Prometheus's Patents Invalid

Prometheus's patents9 recite methods for optimizing the efficacy of thiopurine drugs for use in the treatment of auto-immune diseases, such as Crohn's disease. The asserted claims disclose a method wherein a thiopurine drug is administered, the levels of certain drug metabolites are determined, and specific action is taken based upon the levels of the metabolites. For example, claim 1 of the '623 patent recites: A method of optimizing therapeutic efficacy for treatment of an immune-mediated gastrointestinal disorder, comprising:
administering a drug providing 6-thioguanine to a subject having said immune-mediated gastrointestinal disorder; and determining the level of 6-thioguanine in said subject having said immune-mediated gastrointestinal disorder, wherein the level of 6-thioguanine less than about 230 pmol per 8x108 red blood cells indicates a need to increase the amount of said drug administered to said subject and wherein the level of 6-thioguanine greater than about 400 pmol per 8x108 indicates a need to decrease the amount of said drug subsequently administered to said subject.
Prometheus markets a thiropurine metabolite test incorporating the claimed technology. After discovering that Mayo planned to sell a competing test, Prometheus filed suit in the U.S. District Court for the Southern District of California, alleging Mayo infringed the '623 and '302 patents. The district court granted summary judgment in favor of Mayo, finding the patents claimed ineligible subject matter because they comprised routine data-gathering steps, such as "administering" and "determining," in conjunction with natural phenomena, i.e. drug-metabolite correlations resulting from a bodily process. Specifically, the court found the metabolites were "products of the natural metabolizing of thiopurine drugs, and the inventors merely observed the relationship between these naturally produced metabolites and therapeutic efficiency and toxicity."10 The district court further determined that the patent claims wholly preempted the use of these correlations except as claimed by Prometheus and therefore ruled the patents invalid.

Federal Circuit Applies Machine-or Transformation Test, Finds Patents Claimed Eligible Subject Matter

On appeal, the Federal Circuit applied the machine-or-transformation test of In re Bilski,11 finding Prometheus's patents were "squarely" drawn to statutory subject matter.12 The court noted that although natural phenomena are not per se patentable, their application to a process may be eligible for patent protection. Specifically, the court found the patents "transform[ed] the human body following administration of a drug and the various chemical and physical changes of the drug's metabolites that enable their concentrations to be determined."13 Disputing the district court's characterization of the claim steps as merely data-gathering, the Federal Circuit found that the steps "are part of a treatment protocol, and they are transformative."14 The court did agree with the district court that the claims contained "mental" steps, but found that they did "not detract from the patentability of Prometheus's claimed methods as a whole."15 Accordingly, the Federal Circuit reversed the district court's summary judgment in favor of Mayo. Following the Supreme Court's decision in Bilski v. Kappos,16 the Court granted Mayo's writ of certiorari, vacating the judgment of the Federal Circuit, and remanding the case back to the Federal Circuit for further consideration.17

Federal Circuit Upholds Validity of Prometheus's Patents Under Transformation and Preemption Tests

On remand, the Federal Circuit once again found the asserted patents claimed statutory subject matter.18 The court found that the Supreme Court's most recent decision in Bilski did not dictate a wholly different analysis or result on remand because the Court had not completely rejected the "transformation" test, but merely reduced its importance in judging patentability under Section 101. The court found that the asserted claims satisfied both the "preemption" and "transformation" tests. Specifically, the court noted that Prometheus's claims were a patentable application of naturally occurring correlations and did not wholly preempt all uses of the correlations. The Federal Circuit reaffirmed that the asserted claims "recite specific treatment steps, not just the correlations themselves."19 Applying the "transformation" test, the court again focused on the change that occurs in the body upon administration of any drug, noting that this transformation "is the entire purpose of administering these drugs."20 The Federal Circuit noted that the district court had fundamentally erred in considering the "administering" and "determining" steps to be no more than data-gathering, finding the steps to be "significant" transformative elements of the claimed methods. 21 Accordingly, the court again reversed the judgment of the district court, and Mayo again petitioned for certiorari, which has now been granted by the Supreme Court.

The Labcorp Dissent

While likely granting certiorari in order to shed further light on the scope of patentable subject matter post-Bilski, at least one in the Court may also be eager to revisit the patentability of natural "correlations" first presented to it in Laboratory Corp. of America Holdings v. Metabolite Laboratories, Inc.22 Labcorp had been found liable for inducing others to infringe a patented process involving the correlation of high levels of homocysteine and certain vitamin deficiencies. The Federal Circuit affirmed the infringement finding and Labcorp petitioned the Supreme Court for a writ of certiorari, arguing, among other questions, that a patent claiming a correlation of test results effectively claims a monopoly over a basic scientific relationship. The Court granted review, but later found certiorari to be improvidently granted because Labcorp had not specifically referred to Section 101 in the lower courts to support its patentability arguments. Justices Breyer, Stevens, and Souter, however, dissented from the dismissal, noting that LabCorp had argued the essence of its claim in the lower courts and the Court should now decide "special public interest considerations."23 The dissent noted that patents to scientific correlations "may inhibit doctors from using their best medical judgment . . . spend unnecessary time and energy to enter into license agreements . . . [and] divert resources from the medical task of health care to the legal task of searching patent files."24 The dissenting Justices argued that even if the correlation at issue was patentable, a decision in this case would better inform doctors of their legal obligations and highlight to Congress any inadequacies in the patent system. Turning to the merits of respondents' patent, the dissent argued that extending patent protection to natural phenomena, such as the correlation of test results, "despite its potentially positive incentive effects, would too often severely interfere with, or discourage, development and the further spread of useful knowledge itself."25 While conceding that defining natural phenomena per se is a difficult task, the dissent nevertheless had "little doubt" that the correlations at issue inLabCorp were unpatentable. 26 The respondents argued that even if the correlations were natural phenomena, the process itself was patentable because there was a physical transformation of blood samples during the variety of tests used to measure homocysteine levels. The dissent rejected this view, finding that any transformation occurring during the unpatented step of obtaining the blood test results did not bolster the patentability of the claimed process, which did not recite a specific test for obtaining the results. Indeed, the dissent remarked that the use of any natural phenomena for any purpose "could well involve the use of empirical information obtained through an unpatented means that might have involved transforming matter,"27 but this transformation would not make patentable a bare process claiming the phenomena. The dissent concluded that respondents' patented "process [was] no more than an instruction to read some numbers in light of medical knowledge"28 and constituted an unpatentable natural phenomenon. Following the retirement of Justices Stevens and Souter, only Justice Breyer from the Labcorp dissent remains on the Court. Although his dissent would seem to indicate that Justice Breyer would also vote to find Prometheus's similar patent invalid, there is room for doubt. First, the Labcorp dissent noted that the Federal Circuit never considered the Section 101 patentability issue in finding the patent not invalid, remarking that "further consideration by the Federal Circuit might help us reach a better decision."29 In Mayo, the Federal Circuit has now twice upheld the validity of the patent, and even Justice Breyer may be unwilling to disturb the lower court's considered analysis. Second, the Labcorp dissent focused on the absence of any transformation in the steps of the patent, noting that the patent merely claimed the obtaining of blood test results and their interpretation. Prometheus's patents specifically recited an initial step of drug administration to obtain the test results, a step that the Federal Circuit has twice found to transform the body. Justice Breyer may also agree that the incorporation of this administration step saves the Prometheus patents from invalidity. Third, the Labcorp dissent did not discuss whether the patent at issue preempted all possible uses of the homocysteine/vitamin correlations. On remand, the Federal Circuit had applied this preemption standard to the Prometheus patents, finding no claim was made to the correlations themselves, but rather to treatment methods. Justice Breyer may now consider these factors in finding that Prometheus's patents, unlike that involved in Labcorp, are indeed patentable.

Stage Set for the Supreme Court

The question now presented before the Supreme Court is:
Whether 35 U.S.C. § 101 is satisfied by a patent claim that covers observed correlations between blood test results and patient health, so that the claim effectively preempts all uses of the naturally occurring correlations, simply because well-known methods used to administer prescription drugs and test blood may involve "transformations" of body chemistry.30
Three recent decisions by the Supreme Court provide some insight into how the Court may rule in Prometheus. In all three cases, Global-Tech Appliances Inc. v. SEB S.A.,31 Board of Trustees of Leland Stanford Junior University v. Roche Molecular Systems, Inc.,32 and Microsoft Corp. v. i4i LP,33 the Court affirmed the Federal Circuit's decisions in a seemingly strong vote of confidence in both the lower court and the rights of patentees. These rulings come in stark contrast to recent Supreme Court reversals and criticism of Federal Circuit patent decisions.34 The Court may now be ready to step back from concerns over the proliferation of patents for the "results of ordinary innovation"35 and adhere to established principles of patent law. If this new trend continues, the Court will likely uphold the validity of Prometheus's patents while perhaps shedding further guidance on the scope of patentable subject matter. No matter the result, Prometheus and Mayo, along with doctors, scientists, and most pharmaceutical companies, will be eager to hear the Court's decision sometime around June 2012. Disclaimer This document and any discussions set forth herein are for informational purposes only, and should not be construed as legal advice, which has to be addressed to particular facts and circumstances involved in any given situation. Review or use of the document and any discussions does not create an attorney-client relationship with the author or publisher. To the extent that this document may contain suggested provisions, they will require modification to suit a particular transaction, jurisdiction or situation. Please consult with an attorney with the appropriate level of experience if you have any questions. Any tax information contained in the document or discussions is not intended to be used, and cannot be used, for purposes of avoiding penalties imposed under the United States Internal Revenue Code. Any opinions expressed are those of the author. The Bureau of National Affairs, Inc. and its affiliated entities do not take responsibility for the content in this document or discussions and do not make any representation or warranty as to their completeness or accuracy. ©2014 The Bureau of National Affairs, Inc. All rights reserved. Bloomberg Law Reports ® is a registered trademark and service mark of The Bureau of National Affairs, Inc.

To view additional stories from Bloomberg Law® request a demo now