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U.S. Patents on Medical Diagnostics: Valid…For Now

By Linda B. Truong and Seth D. Levy
[June 2006]

Patent protection is the primary vehicle by which not-for-profit institutions commercialize technology developed on-campus, and the chief legal tool that companies use to maintain a market advantage for their products and services. Patents can be extraordinarily valuable assets for any organization, but the U.S. Supreme Court has recently brought into question whether one significant category of such patents is valid. Medical diagnostic patents were the subject of Laboratory Corp. of Am. Holdings v. Metabolite Labs., Inc. Not only does the case have important implications for patent owners, but also for the clinicians and institutions that utilize medical diagnostic technologies.

On June 22, 2006, the U.S. Supreme Court dismissed the case of Laboratory Corp. of Am. Holdings v. Metabolite Labs., Inc.¹ Patent owners on medical diagnostic technologies can thus breathe a sigh of relief, as the Court’s decision in this case could have rendered invalid a host of patents on medical diagnostic technologies as claiming unpatentable subject matter under 35 U.S.C. §101. Although the Court did not elaborate on its rationale for suddenly dismissing the case, it is widely believed that it was for procedural and not substantive reasons. In fact, despite extensive briefing on the issue before the Court, LabCorp had not raised the question of patentable subject matter at the district court level, and the Court of Appeals for the Federal Circuit thus did not opine on the issue when the case was first appealed. Still, a 15-page dissent by Justice Breyer, which was joined by Justices Stevens and Souter, suggested that not only was this case ripe for review by the Court, but that at least these Justices would likely have found the patent claims at issue to be invalid. Although not binding legal precedent, it is entirely likely that patent defendants in future cases will be mindful of the LabCorp dissent, and raise similar defenses regarding subject matter patentability in connection with this type of technology.

Patent protection is granted to “promote the Progress of Science and useful Arts.”² The broad range of innovation that is eligible for patent protection is described at 35 U.S.C. §101, which defines “patentable subject matter.” Courts have recognized that “[p]henomena of nature, though just discovered, mental processes, and abstract intellectual concepts are…the basic tools of scientific and technological work,”³ but have long held that fundamental scientific principles and laws of nature are regarded as “part of the storehouse of knowledge” and “free to all men and reserved exclusively to none.”⁴ In sum, “laws of nature” are not patentable subject matter. However, “an application of a law of nature…to a known…process may well be deserving of patent protection” if it “produces a useful, concrete and tangible result.”⁵

The specific question in LabCorp was whether the correlation of a test result to a medical condition constitutes unpatentable subject matter as a mere “law of nature.” The inventor had essentially discovered a law of nature; namely, that elevated levels of homocysteine in the blood tend to indicate a deficiency in the B vitamins, cobalamine or folate. Capitalizing on this discovery, Metabolite’s U.S. Patent No. 4,940,658⁶ claims “[a] method for detecting a deficiency of cobalamin or folate in warm-blooded animals comprising the steps of: assaying a body fluid for an elevated level of total homocysteine; and correlating an elevated level of total homocysteine in said body fluid with a deficiency of cobalamin or folate.” The method, therefore, includes two steps: (i) assaying a body fluid, and (ii) correlating the measure with a mineral deficiency. The first step (i.e., testing the blood for levels of homocysteine) is not a novel concept. Rather, the novel and non-obvious portion of the claim relates primarily to the scientific discovery -- the second, “correlating” step. If the claim is taken as a whole, it passes muster under 35 U.S.C. §101 as relating to patentable subject matter, at least, based on current case law. If, however, focus is placed on the subset of the claim that contributes to its novelty and non-obviousness, this portion of the claim could fail as an unpatentable “law of nature.”

The Court had originally granted certiorari to determine the question of whether a patent can claim rights to a basic scientific relationship used in medical treatment if the claim is limited to “correlating” test results. The specific question on review was as follows: “Whether a method patent setting forth an indefinite, undescribed, and non-enabling step directing a party simply to ‘correlat[e]’ test results can validly claim a monopoly over a basic scientific relationship used in medical treatment such that any doctor necessarily infringes the patent merely by thinking about the relationship after looking at a test result.” In its invitation to the U.S. Solicitor General to file a brief in this case, the Court further posed the issue of whether the patent is invalid because “one cannot patent laws of nature, natural phenomena, and abstract ideas” (i.e., whether the invention is patentable subject matter under §101). The issue of patentable subject matter was not formally litigated in the lower courts and the Court of Appeals for the Federal Circuit had not directly considered the question. Despite this procedural posture, the Supreme Court does have authority to consider this issue sua sponte, and until June 22, 2006, it appeared that it was willing to do so.

Justice Breyer’s dissent to the dismissal of LabCorp indicated that, at least in his opinion and in the minds of the two Justices that joined him, the process of “correlating” test results does not amount to patentable subject matter. In a brief review of the merits of the case, the dissent opined that the invention “simply described the natural law at issue in the abstract patent language of a process.”⁷ In response to the argument that the patent claim was to a process that involves the application of a law of nature, the dissent focused on the step that the inventive process embodied. Justice Breyer determined that “aside from the unpatented test, [the process embodies] the correlation between homocysteine and vitamin deficiency,”⁸ which is a natural phenomenon.

If the Court had issued a ruling in this case, it could have had a profound impact on the patent protection sought, obtained, and enforced by the medical diagnostics industry and, depending upon the breadth of the ruling, perhaps to numerous other industries as well. Furthermore, as recognized by the dissent, a decision upholding the patent claim may subject physicians to restrictions which may “inhibit doctors from using their best medical judgment[,] force doctors to spend unnecessary time and energy to enter into license agreements[,] divert resources from the medical task of health care to the legal task of searching patent files for similar simple correlations[, and] raise the cost of healthcare while inhibiting its effective delivery.”⁹ However, if the patent was rendered invalid for claiming unpatentable subject matter, thousands of similar “correlation patents” could have been invalidated and the substantial investments by patentees would have been lost.

Although the Court’s dismissal of LabCorp and the corresponding dissent are not binding legal precedent, this may provide some insight into the way in which the issue will be decided in the future. Today, “correlation patents” remain valid under 35 U.S.C. §101, but the ground on which they stand has been shaken.

Footnotes

For further information, please contact:

Linda B. Truong Los Angeles, California (213) 633-6874 lindatruong@dwt.com

Seth D. Levy Los Angeles, California (213) 633-6869 sethlevy@dwt.com

This Life Sciences Advisory Bulletin is a publication of the Life Sciences Group of Davis Wright Tremaine LLP. Our purpose in publishing this Advisory Bulletin is to inform our clients and friends of developments in life sciences law. It is not intended, nor should it be used, as a substitute for specific legal advice as legal counsel may be given only in response to inquiries regarding particular situations.

Copyright © 2006, Davis Wright Tremaine LLP.

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