LEGAL VIEW: SCOTUS on patent eligibility of medical diagnostics

By Andrew K. Gonsalves

The Daily Record Newswire

Medical diagnostic tests are often used by health care providers to aid in determining whether a patient has a particular disease or medical condition. Over the last decade, advances in the field of molecular biology have enabled researchers to better understand how a patient's unique metabolic, genetic and proteomic profile might be used to develop more targeted and effective diagnostic tests.

Personalized medicine, which is a relatively new but growing approach to health care, relies on the refinement of these customized diagnostic tests to assist in developing therapeutic treatments tailored to an individual patient's needs. Therefore, the Supreme Court's recent decision to strike down certain medical diagnostic patent claims has caused some concern and uncertainty for innovators in the field of personalized medicine.

On March 20, the Supreme Court, by unanimous decision, handed down its opinion in Mayo Collaborative Services v. Prometheus Laboratories, Inc. (No. 10-1150), which addressed the issue of patent eligibility of certain types of medical diagnostic patent claims.

The Prometheus decision concerned U.S. Patent Nos. 6,355,623 and 6,680,302, both of which relate to diagnostic tests for determining the appropriate dosages for a given patient of a thiopurine drug used to treat gastrointestinal autoimmune diseases such as Crohn's disease and ulcerative colitis.

In an opinion written by Justice Stephen Breyer, the Supreme Court reversed the Federal Circuit and held that the contested diagnostic process claims were not patent eligible under 35 U.S.C. § 101.

In brief, the Supreme Court found that the claims at issue recited "laws of nature" that were not themselves patent-eligible. In order to meet the patent eligibility requirements of § 101, the Supreme Court held that, in addition to reciting these laws of nature, the claims must also include "additional features that provide practical assurance that the process is more than a drafting effort designed to monopolize the law of nature itself." '

The court identified the laws of nature recited in the claims as being the relationships between concentrations of certain thiopurine metabolites (e.g., 6 thioguanine) in the blood and the likelihood that a thiopurine drug dosage will prove ineffective or cause harm. While the claims included an "administering" step, a "determining" step, and "wherein" clauses, the court found that any additional features recited in the claims were "not sufficient to transform unpatentable natural correlations into patentable applications of those regularities."

The "administering" step involved administering a drug providing 6-thioguanine to a subject having an immune-mediated gastrointestinal disorder. The court found that this step simply referred to the relevant audience, namely, doctors who treat patients with thiopurine drugs. The court also noted that treating these diseases with thiopurine drugs was already well known.

The "determining" step involved determining the level of 6-thioguanine in the subject. The court found that this feature merely told the doctor to determine the level of the relevant metabolites in the blood. Finally, the "wherein" clauses set forth the particular levels of 6-thioguanine in the blood that correlated to a need to either increase or decrease the drug to be subsequently administered to the subject. The court determined that these clauses simply told a doctor about the relevant natural laws, and, at most, suggested that the doctor take those laws into account when treating his patient.

In sum, the court concluded that any additional steps contained in the claims at issue consisted of well-understood, routine, conventional activity already engaged in by the scientific community, and, therefore, were not patent eligible.

In the short time since its issuance, the Prometheus decision has generated a good deal of discussion among those in the biotechnology industry.

Unfortunately, the Supreme Court did not provide explicit guidance on how the particular claims in Prometheus could have been amended to meet the requirements of § 101; accordingly, at present, there is little consensus of how the Prometheus decision will impact and influence the continued growth, innovation, patent procurement and commercialization of these promising medical technologies.

While many interested parties are concerned about the uncertainty created by the Prometheus decision, there are some practical considerations to be aware of with respect to medical diagnostic claims. It appears that, at the very least, diagnostic process claims similar in structure to those in Prometheus should require some post-solution activity.

For example, in Prometheus, rather than merely suggesting an increase or decrease in the dosage of the thiopurine drug, the claim could have, at least, positively required the subsequent administration of the higher or lower dosage indicated by the metabolite levels found in the patient's blood.

However, in many instances, this would not be an adequate approach, as some patentees are mainly interested in patent coverage for the use of their diagnostic test, not for the subsequent administration of a drug dosage informed by the test's results.

Association for Molecular Pathology v. Myriad Genetics et al. (No. 11-725, U.S. Supreme Court): On the heels of its decision in Prometheus, on March 26, the Supreme Court granted certiorari review of the Myriad Genetics case, which deals with the patent eligibility of patent claims directed to, inter alia, isolated human breast cancer genes.

Without rendering an opinion, the Supreme Court vacated the Federal Circuit's previous decision and remanded the case back to the Federal Circuit for further consideration in light of the Supreme Court's decision in Prometheus. The Myriad Genetics case, like Prometheus, will be closely watched by the biotechnology industry and patent practitioners.

SmartGene Inc. v. Advanced Biological Laboratories SA (No. 08-00642, D.D.C.): On March 30, the District Court for the District of Columbia became the first lower court to issue an opinion that applied the Supreme Court's holding in Prometheus.

In the SmartGene case, the District Court found the subject patent claims to be invalid as being directed to ineligible subject matter under 35 U.S.C. § 101. The patents at issue relate to a system, method, and computer program for guiding the selection of therapeutic treatment regimens for complex disorders by ranking available treatment regimens and providing advisory information. In rendering its decision, the District Court confirmed the patent eligibility statute of § 101 as presenting a threshold inquiry into patent validity. The court then went on to discuss Prometheus as being one "guidepost" in deciding the issue of patent eligibility.

While the impact of the Prometheus decision is still to be determined, innovators of diagnostic processes and personalized medicine inventions should evaluate their diagnostic process patent claims pending before the U.S. Patent and Trademark Office and consider whether they need to be amended to bring them in line with the Prometheus decision.

Similarly, those with issued patents containing diagnostic claims should immediately evaluate those claims to determine whether reissue is desirable and/or feasible, particularly if the patent issued less than two years ago.


Andrew K. Gonsalves is a senior attorney and member of the Biotechnology Practice Group of Heslin Rothenberg Farley & Mesiti PC. He can be reached by email at

Published: Wed, Apr 18, 2012


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