Federal Circuit Affirms Patent-Ineligibility Of Diagnostic Method Claims

On April 1, 2019, the Court of Appeals for the Federal Circuit (CAFC) issued a decision in Cleveland Clinic Foundation v. True Health Diagnostics LLC affirming a decision by the U.S District Court for the Eastern District of Virginia that held claim 1 of U.S. Patent No. 9,575,065 and claims 1 and 2 of U.S. Patent No. 9,581,597 invalid under 35 U.S.C. §101 for being directed to a natural law without reciting an inventive concept beyond the natural law itself.

The Cleveland Clinic Foundation and Cleveland HeartLab, Inc., (collectively, “Cleveland Clinic”) appealed from a decision of the United States District Court for the Eastern District of Virginia, dismissing their complaint for patent infringement against True Health Diagnostics LLC under Rule 12(b)(6) and holding claim 1 of U.S. Patent 9,575,065 (the “’065 patent”) and claims 1 and 2 of U.S. Patent 9,581,597 (the “’597 patent”) invalid under 35 U.S.C. § 101 as directed to an ineligible natural law. Cleveland Clinic Foundation v. True Health Diagnostics LLC, No. 1:17-cv-00198-LMB-IDD, 2017 WL 3381976 (E.D. Va. Aug. 4, 2017).

The ‘065 and ‘597 patents disclose diagnostic tests for characterizing an individual’s risk of developing or having a cardiovascular disease. These diagnostic tests are based on the discovery that patients with coronary artery disease (CAD) have significantly greater levels of leukocyte and blood myeloperoxidase (MPO) levels. The sole claim of the ‘065 patent reads as follows:

1. A method of detecting elevated MPO mass in a patient sample comprising:

a) obtaining a plasma sample from a human patient having atherosclerotic cardiovascular disease (CVD); and

b) detecting elevated MPO mass in said plasma sample, as compared to a control MPO mass level from the general population or apparently healthy subjects, by contacting said plasma sample with anti-MPO antibodies and detecting binding between MPO in said plasma sample and said anti-MPO antibodies.

The ‘597 patent has only two claims, which read as follows:

1. A method for identifying an elevated myeloperoxidase (MPO) concentration in a plasma sample from a human subject with atherosclerotic cardiovascular disease comprising:

a) contacting a sample with an anti-MPO antibody, wherein said sample is a plasma sample from a human subject having atherosclerotic cardiovascular disease;

b) spectrophotometrically detecting MPO levels in said plasma sample;

c) comparing said MPO levels in said plasma sample to a standard curve generated with known amounts of MPO to determine the MPO concentration in said sample; and

d) comparing said MPO concentration in said plasma sample from said human subject to a control MPO concentration from apparently healthy human subjects, and identifying said MPO concentration in said plasma sample from said human subject as being elevated compared to said control MPO concentration.

2. The method of claim 1, further comprising, prior to step a), centrifuging an anti-coagulated blood sample from said human subject to generate said plasma sample.

The Federal Circuit noted that it had previously addressed the subject matter eligibility of a parent patent, U.S. Patent No. 7,223,552, in Cleveland Clinic Foundation v. True Health Diagnostics, LLC, 859 F.3d 1352 (Fed. Cir. 2017) (“Cleveland Clinic I”), in which the Court held that the methods claimed in the parent ‘552 patent were invalid under § 101 as directed to the ineligible natural law that blood MPO levels correlate with atherosclerotic CVD (holding that the claimed method “starts and ends” with observation of “naturally occurring phenomena,”). In Cleveland Clinic I, the Federal Circuit further held that, because the patent did not purport to have invented any of the biological techniques used to detect MPO or the statistical methods used to compare a patient’s MPO levels to the control group, the claims recited no further inventive concept sufficient to transform the nature of the claims into a patent-eligible application of the natural law. According to the Federal Circuit, the claims of the ‘065 and ‘597 patents recite methods of identifying and detecting MPO, in contrast to the parent ’552 patent’s claimed method of assessing atherosclerotic CVD risk from blood MPO levels.

Cleveland Clinic argued in the appeal proceedings that the claims of the ‘065 and ‘597 patents are not directed to a natural law, but to the technique of using an immunoassay to measure the blood MPO levels of patients with atherosclerotic CVD. Cleveland Clinic further asserted that the correlation between blood MPO levels and atherosclerotic CVD is not a natural law because it can only be detected using certain techniques. According to Cleveland Clinic, prior art techniques were either too invasive (e.g., detecting MPO in samples of excised atherosclerotic lesions) or failed to predict CVD risk. Cleveland Clinic also argued that, while performing an immunoassay on blood samples was known, using the immunoassay to detect the correlation between blood MPO levels and atherosclerotic CVD supplies an inventive concept sufficient to transform the claims into patent-eligible subject matter. True Health countered the arguments of Cleveland Clinic. True Health responded that the correlation between atherosclerotic CVD and blood MPO levels is a natural law because it exists in nature apart from human intervention and that using known techniques in a standard way to observe the natural law neither renders the claims directed to something other than this natural law nor supplies an additional inventive concept.

The Federal Circuit agreed with True Health and concluded, as it did in Cleveland Clinic I, that the claims of the ‘065 and ‘597 patents are directed to the natural law that blood MPO levels correlate with atherosclerotic CVD. With regard to the Cleveland Clinic’s primary argument that, unlike the ’552 patent claims, the claims at issue are not directed to “assessing a test subject’s risk of having atherosclerotic [CVD]” by comparing the subject’s MPO levels to a control group, but rather to “techniques for detecting elevated levels of MPO in the blood of patients having CVD”, the Federal Circuit found this distinction (as the district court did) to be “overly superficial”. More particularly, the Federal Circuit commented as follows:

“The claims are not directed to new techniques for performing an immunoassay to detect a patient’s blood MPO levels. They only recite applying known methods to detect MPO levels in plasma, comparing them to standard MPO levels, and reaching a conclusion: that the patient’s blood MPO levels are elevated in comparison to a control group. This conclusion is simply another articulation of the natural law that blood MPO levels correlate with atherosclerotic CVD. Thus, as we held in Cleveland Clinic I, the claims are directed to the patent-ineligible natural law that blood MPO levels correlate with risk of atherosclerotic CVD. Cf. Flook, 437 U.S. at 593 (stating that patent eligibility does not turn “on the draftsman’s art”). The rephrasing of the claims does not make them less directed to a natural law.”

“Nor is the fact that blood MPO levels correlate with atherosclerotic CVD any less a natural law because it can only be observed by use of certain techniques. Many scientific techniques will not reveal a correlation between blood MPO levels and atherosclerotic CVD. But the same is true of the natural laws at issue in our previous cases. See“Nor is the fact that blood MPO levels correlate with atherosclerotic CVD any less a natural law because it can only be observed by use of certain techniques. Many scientific techniques will not reveal a correlation between blood MPO levels and atherosclerotic CVD. But the same is true of the natural laws at issue in our previous cases. See Ariosa, 788 F.3d at 1376 (that paternally inherited cffDNA is present in maternal blood plasma); Athena Diagnostics, Inc. v. Mayo Collaborative Servs., LLC, 915 F.3d 743, 747 (Fed. Cir. 2019) (that some Myasthenia gravis patients “generate autoantibodies to a membrane protein called MuSK”). These laws of nature exist regardless of the methods used by humans to observe them. Inadequate measures of detection do not render a natural law any less natural. Thus, we held the claims at issue in those cases directed to a natural law, and we do so again here.”

Cleveland Clinic also argued that the district court failed to give the appropriate deference to subject matter eligibility guidance published by the PTO, as required by Skidmore v. Swift & Co., 323 U.S. 134 (1944), and also that the district court erred by not granting Skidmore deference to the examiner’s decision to allow the patents’ applications to issue in light of the guidance, specifically Example 29–Claim 1. True Health counter-argued that the PTO guidance is neither persuasive nor relevant to the eligibility of the claims at issue, and that the district court correctly found that the claim 1 of Example 29 of the PTO guidance is directed to a method of detecting a protein in a plasma sample without linking the results to a disease or other natural phenomenon.

The Federal Circuit agreed with True Health and declined to follow the PTO’s Example 29–Claim 1 and concluded that the district court did not err in its consideration of the PTO’s subject matter eligibility guidance. The Federal Circuit’s opinion said:

“While we greatly respect the PTO’s expertise on all matters relating to patentability, including patent eligibility, we are not bound by its guidance.  And, especially regarding the issue of patent eligibility and the efforts of the courts to determine the distinction between claims directed to natural laws and those directed to patent-eligible applications of those laws, we are mindful of the need for consistent application of our case law.”

Thus, the Federal Circuit affirmed the decision of the district court that held claim 1 of ‘065 patent and claims 1 and 2 of ‘597 patent invalid under 35 U.S.C. § 101 as directed to an ineligible natural law.

Author: Mr. Antony David, Principal Associate – Pharmaceutical-Life Sciences Practice Group at Khurana & Khurana, Advocates and IP Attorneys. In case of any queries please contact/write back to us at antony@khuranaandkhurana.com .

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