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Federal Circuit clarifies patent-eligibility for diagnostic method patents: Endo v. Teva and Natural Alternatives v. Creative Compounds.

Zachary Silbersher

The Federal Circuit has recently issued two precedential decisions that clarify when method-of-use and diagnostic patents are directed to eligible subject matter rather than natural laws.  Some clear guidelines are solidifying that should make enforcement of these principally pharmaceutical-type patents easier to handicap.

Pharmaceutical patents come in many different forms.  Some forms include method-of-use patents, namely, a method of administering this drug to treat that disease.  Sometimes those method-of-use patents contain a diagnostic determination.  For instance, the claim may take the form: measure the patient’s X, and if X is above or below a certain threshold, then administer a lower or higher dosage of drug Y. 

Often times, the diagnostic components of these patents—measuring some criteria in the patient before determining how to administer the drug—is based upon a discovery by the inventors.  For instance, in Endo Pharmaceuticals, Inc. v. Teva Pharmaceuticals USA, Inc., 2017-1240 (Mar. 28, 2019), the asserted patent was based upon the purported discovery that patients with renal impairment required less oxymorphone to sustain the same blood concentration levels.  More specifically, the patent disclosed a study showing that plasma AUC for oxymorphone correlated with the degree of a patient’s renal impairment, which was indicated by their creatinine clearance rate.  Given that discovery, the patent was directed to a method of “measuring a creatinine clearance rate of a patient” and, based upon that measurement, administering a lower dosage of oxymorphone to sustain an average 12-hour AUC of about 21 ng-hr/mL.

The issue with these types of patents is that the inventor’s discovery, namely, the relationship between the patient’s measured criteria and the condition, is technically a law of nature.  And under Section 101 of the Patent Statute, laws of nature cannot be claimed in a patent.  The theory is that is laws of nature could be patented, that would preempt whole fields of scientific research.  Likewise, when courts wrestle with the question of whether a diagnostic patent is directed to ineligible subject matter, they fundamental inquiry is whether the patent simply claims a law of nature.  Indeed, in the Endo case, the district court originally found the patent simply covered a law of nature—the relationship between the severity of renal impairment and the bioavailability of oxymorphone—to determine the correct dose.    

The Federal Circuit disagreed.  In finding the patent was not directed to ineligible subject matter under § 101, the Court explained that patent may have been based upon the inventor’s discovery of a law of nature—namely, the relationship between renal impairment and oxymorphone’s bioavailability.  But the patent did not simply claim that law of nature.  Rather, it was directed to a specific method of treatment, namely, a method to treat pain in renally-impaired patients.   

In another recent case, Natural Alternatives Int’l Inc. v. Creative Compounds, the Federal Circuit applied the same reasoning to reverse a district court’s finding that a method-of-use patent was also simply claiming a natural law.  2018-1295 (Fed. Cir. Mar. 15, 2019).  The patents covered a method of administering beta-alanine, which is an amino acid, to increase the anaerobic working capacity of an athlete’s muscles.  (Another asserted patent involved ingesting beta-alanine to regulate hydronium ion concentration in tissue.)  The district court held the patents simply covered a natural law—namely, beta-alanine, a natural substance, will increase a human’s anaerobic working capacity by increasing carnosine concentration in human tissue. 

The Federal Circuit disagreed.  Much like in Endo, it held that the patent does not simply embody the discovery that ingesting bet-alanine will increase levels of creatine, and thus, improve an athlete’s performance.  Rather, the patens “require that an infringer actually administer the dosage form in the manner claimed.”  (Slip Op. at 8).  In other words, the patents required an affirmative treatment step.

In both cases, the Court relied heavily on Vanda Pharmaceuticals Inc. v. West-Ward Pharmaceuticals Int’l Ltd., 887 F.3d 1117 (Fed. Cir. 2018), and held the claims legally indistinguishable.  In Vanda, the patent was based upon the discovery that patients who are poor CYP2D6 metabolizers can be treated more safely—and avoid risks of cardiac problems—with lower dosages of iloperidone.  The patent covered a method of treating schizophrenia with iloperidone, where the dose is adjusted based on whether the patient is a CYP2D6 poor metabolizer. 

In both Vanda and Endo, for instance, the patent included a testing step and an administration step.  In Vanda, the testing step was genetic testing to determine if the patient was a CYP2D6 poor metabolizer, and the administration step was administering 12 mg/day of iloperidone if the patient is a CYP2D6 poor metabolizer, and more if the patient is not.  In Endo, the testing step was measuring a patient’s creatinine clearance rate to determine the degree of the patient’s renal impairment, and the administration step was administering a lower dosage based on the patient’s degree of renal impairment to sustain average AUC of oxymorphone over 12 hours at a specified amount.

In Endo, the Court also distinguished the Supreme Court’s decision in Mayo Collaborative Servs. v. Prometheus Labs., Inc., 566 U.S. 66 (2012), where the patent was deemed to be subject to ineligible subject matter.  Most importantly, the Court found that the patent in Mayo was not directed to actually treating a patient—“the claim as a whole was not directed to the application of a drug to treat a particular disease.”  (Endo, Slip Op. at 12).

The patent claim in Mayo did, in fact, have an administering step, which recited, “administering a drug providing 6-thioguanine to a subject having said immune-mediated gastrointestinal disorder.”  Yet, the Court in Endo distinguished Mayo’s administering step from the administering steps in Endo and Vanda.  Specifically, in Endo and Vanda, the administration step—the step involving actually giving the drug to a patient—was based upon the results of the testing step.  Indeed, the testing step preceded the administration step.  By contrast, the administration step in Mayo was the first step in the claim.  It was not based upon prior testing.  Rather, in Mayo, the drug is first administered to the patient, and next, the patient’s level of 6-thioguanine is measured, and the results of that measurement “indicates a need” to either increase or decrease the dosage.

 Similarly, the Court in Endo also distinguished Ariosa Diagnostics, Inc. v. Sequonom, Inc., 788 F.3d 1371 (Fed. Cir. 2015).  There, the patent was directed not to a method of treatment, but rather to a method of detecting paternally-inherited cell-free fetal DNA.  That, the Court held, was simply directed to applying routine techniques to detect what the inventors purported to discover—namely, the presence of cell-free fetal DNA in maternal plasma or serum.  The take-away is that a patent directed to detecting an aspect of a patient is presumably not eligible, whereas a patent directed using that detection to change some aspect of the patient is eligible.

These cases thus provide guidance for when disagnostic, method-of-treatment patents will pass muster under Section 101.  In short, to avoid claiming ineligible subject matter, it is helpful that the patent is directed to treating a specific condition.  In Natural Alternatives, the Court stated that the claims “require specific steps to be taken in order to bring about a change in a subject, altering the subject’s natural state.”  (Slip Op. at 10-11).