Are Medical Diagnostic Tests Patentable?  The United States Supreme Court Weighs in With the Mayo v. Prometheus Decision

Stan Gibson's Notes from the Inventor Underground

Are Medical Diagnostic Tests Patentable? The United States Supreme Court Weighs in With the Mayo v. Prometheus Decision

Patent and Technology trial lawyer Stan Gibson discusses a recent Supreme Court decision that calls into question the patentability of diagnostic methods.

Stan Gibson, Intellectual Property Trial Attorney

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In a widely watched and anticipated decision, the United States Supreme Court reversed the Federal Circuit’s decision in Mayo Collaborative Services v. Prometheus Laboratories, Inc., which had upheld the patentability of a medical diagnostic test that measured metabolites in human blood. The Supreme Court’s decision has wide ranging implications for the medical diagnostic community, as it throws into question the patentability of medical diagnostic tests and may raise patentability issues for other industries as well.

A typical claim of the patent-in-suit reads as follows:

"A method of optimizing therapeutic efficacy for treatment of an immune-mediated gastrointestinal disorder, comprising:

(a) administering a drug providing 6-thioguanine to a subject having said immune-mediated gastrointestinal disorder; and

(b) determining the level of 6-thioguanine in said subject having said immune-mediated gastrointestinal disorder,

wherein the level of 6-thioguanine less than about 230 pmol per 8×108 red blood cells indicates a need to increase the amount of said drug subsequently administered to said subject and

wherein the level of 6-thioguanine greater than about 400 pmol per 8×108 red blood cells indicates a need to decrease the amount of said drug subsequently administered to said subject." 6,355,623 patent, col. 20, ll. 10-20.

Justice Breyer authored the unanimous opinion of the Supreme Court and started the opinion by quoting from Section 101 of the Patent Act that defines patentable subject matter: "Whoever invents or discovers any new and useful process, machine, manufacture, or composition of matter, or any new and useful improvement thereof, may obtain a patent therefore, subject to the conditions and requirements of this title." 35 U.S.C. §101.

Justice Breyer next noted that the "Court has long held that this provision contains an important implicit exception. ‘[L]aws of nature, natural phenomena and abstract ideas’ are not patentable." Justice Breyer explained that "Einstein could not patent his celebrated law that E=mc²; nor could Newton have patented the laws of gravity." Justice Breyer did note, however, that the Court has also held that "’a process is not unpatentable simply because it contains a law of nature or a mathematical algorithm … and added that ‘an application of a law of nature or mathematical formula to a known structure or process may well be deserving of patent protection.’"

Writing on behalf of the Court, Justice Breyer stated that this case "lies at the intersection of these basic principles. It concerns patent claims covering processes that help doctors who use thiopurine drugs to treat patients with autoimmune disease determine whether a given dosage will be ineffective or induce harmful side-effects." Justice Breyer then framed the issue for decision as follows: "The claims purport to apply natural laws describing the relationships between the concentration in the blood of certain thiopurine metabolites and the likelihood that the drug dosage will be ineffective or induce harmful side-effects. We must determine whether the claimed processes have transformed these unpatentable natural laws into patent eligible applications of those laws."

After stating that prior cases warn the Court against upholding patents that claim processes that too broadly preempt the use of a natural law and that these cases insist that a process that focuses upon the use of a natural law must also contain other elements or a combination of elements, the Court found that the process claims at issue here did not satisfy those requirements. "We find that the process claims at issue here do not satisfy these conditions. In particular, the steps in the claimed processes (apart from the natural laws themselves) involve well-understood, routine, conventional activity previously engaged in by researchers in the filed. At the same time, upholding the patents would risk disproportionately tying up the use of the underlying natural laws, inhibiting their use in the making of further discoveries."

Thus, the Court found that the Prometheus patents set forth laws of nature, "[n]amely, relationships between concentrations of certain metabolites in the blood and the likelihood that a dosage of a thiopurine drug will prove ineffective or cause harm." The Court reached this conclusion by categorizing the patents into three steps, consisting of an administering step, a "wherein" clause describing the relevant natural law and a third determining step. With respect to the administering step, the Court found that this merely refers to the relevant audience, i.e., the doctors who treat patients. The "wherein" clause merely described the natural law. The third step, the determining step only tells the doctor to determine the level of the relevant metabolites in the blood. The Court found that this step merely told the doctors to engage in "well-understood, routine, conventional activity previously engaged in by scientists who work in the field." Finally, the Court found that "the three steps as an ordered combination adds nothing to the laws of nature that is not already present when the steps are considered separately."

Accordingly, the Court found that the patents were not valid. "The upshot is that the three steps simply tell doctors to gather data from which they may draw an inference in light of the correlations. To put the matter more succinctly, the claims inform a relevant audience about certain laws of nature; any additional steps consist of well-understood, routine, conventional activity already engaged in by the scientific community; and those steps, when viewed as a whole, add nothing significant beyond the sum of their parts taken separately."

Even after reaching this conclusion, the Court continued, in a third section of the opinion, to criticize the Federal Circuit decision. In noting that the Federal Circuit reasoned that the claimed processes were patent eligible because they involve transforming the human body by administering the drug and transforming the blood by analyzing it to determine metabolite levels, the Supreme Court found that the second step did not satisfy the transformation test. The Supreme Court reached this conclusion because science could develop a different test for determining metabolite levels that did not involve such a transformation: "And the second step could be satisfied without transforming the blood, should science develop a totally different system for determining metabolite levels that did not involve such a transformation."

* * *

The Supreme Court’s decision in Mayo raises more questions than it answers and it simultaneously calls into question the patentability of diagnostic methods that have wide ranging value. The effects of Mayo on the rapidly growing $20 billion U.S. market for in vitro diagnostics remain to be seen. The Supreme Court invalidated the patent but did not provide clear guidance on what types of diagnostic tests may remain patentable; its statement that neither Newton’s law of gravity nor Einstein’s E=mc² formula could have been patented was not particularly helpful.

The third section of the opinion is particularly odd because the Court reasoned that science could develop a different test in the future that might not involve a transformation. Yet, science would only discover such a test through the type of novel, original concept that is usually found to be patentable.

Regardless, given the lack of guidance from the Supreme Court’s decision, we can expect further decisions from lower court and the Federal Circuit on the patentability of medical diagnostic methods where both sides of the dispute will have plenty to argue.

Mayo Collaborative Services, dba Mayo Medical Laboratories, et al. v. Prometheus Laboratories, Inc. Case No. 10–1150.