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On March 20, 2012, the Supreme Court of the United States issued its unanimous opinion in Mayo Collaborative Services v. Prometheus Laboratories, Inc.  This decision is the latest “landmark” decision in patent law that has left practitioners, the United States Patent and Trademark Office, and the courts scratching their heads wondering how the legal landscape will change.

The case came about as a result of Prometheus’ personalized medicine patents that related to the use of thiopurine drugs in the treatment of autoimmune diseases. More specifically, Prometheus patents embodied the findings that concentrations in a patient’s blood of the metabolite from the thiopurine drug above a certain level could prove toxic, while concentrations of the metabolite lower than a certain level would prove ineffective. Prometheus developed diagnostic kits which it sold to a number of customers, including Mayo.  However, in 2004, Mayo announced that it was going to make and sell its own diagnostic test.  Prometheus sued for infringement of two of its patents.

The lower court held that, although Mayo’s diagnostic tests infringed Prometheus’ patents, Mayo was entitled to judgment as the patents in question were invalid for effectively claiming “natural laws or natural phenomena,” which have long been held ineligible for patent protection. On appeal from this decision, the Court of Appeals for the Federal Circuit reversed the lower court’s decision, holding that the steps recited by the patent were sufficiently transformative.  The Supreme Court of the United States granted certiorari, vacated the judgment and remanded the case back to the Federal Circuit to again consider the case in the light of Bilski v. Kappos, an intervening court decision.  Bilski held that the machine or transformation test is not the definitive test, but rather only an important tool or clue to find patentable subject matter.  The Federal Circuit again held the patents valid and infringed.

The Supreme Court then took up the case and ultimately held the patents in question invalid as they “effectively claim the underlying laws of nature themselves.”  In ruling, the Court reasoned that both patents could ultimately be boiled down into three distinct steps: a step where the doctor would administer the drug to the patient, a step where the doctor would determine the level of metabolite in the patient’s blood, and a third “wherein” step that advised doctors to take into account a natural law and adjust the dosage of the drug given to the patient.  The first two of these steps, as the Court reasoned, are well known in the field of medicine and thus could not form the basis for a valid patent.  The third step was the step that, as the Court held, tried to claim the laws of nature.  More distinctly, the Court held that there was nothing claimed in the patents that pushed the idea beyond claiming the unpatentable natural law itself and into the realm of claiming an application of the natural law.

Many legal minds have commented on this case with opinions diverging in all directions.  The United States Patent and Trademark Office has already sent out an internal memo instructing patent examiners on how to take into account the Supreme Court’s mandate regarding patent eligible subject matter.  Practitioners and scholars are just now beginning to see how the lower courts will handle this change in law.  It will most likely be some time before more concrete rules are in place.

Those interested should keep an eye on the Federal Circuit as it will hear arguments in Association for Molecular Pathology v. USPTO and Myriad Genetics on July 20, 2012 – a case that should speak directly to the impact of Mayo v. Prometheus.

This article reflects the author's personal views, which may differ from the views of other Carr & Ferrell LLP employees. Our blog articles are neither opinions of the Firm nor legal advice on which you should rely. Please review our disclaimer.

Michael Adelsheim is an associate in the Intellectual Property Practice Group of Carr & Ferrell LLP. Mr. Adelsheim specializes in intellectual property law matters including the preparation and prosecution of U.S. patent applications, strategic intellectual property planning and patent portfolio management for both established and start-up clients.