Supreme Court Holds That Medical Diagnostic Method is Not Patentable Subject Matter

March 21st, 2012

By: John R. Harris

On March 20, 2012 a unanimous Supreme Court held that a patent claim directed to a method of optimizing therapeutic efficiency for treatment of a disease involving (a) administering a certain drug, and (b) determining the level of the drug in a subject (e.g. by a test kit), is not patentable subject matter. Mayo Collaborative Services d/b/a Mayo Medical Laboratories, et. al. v. Prometheus Laboratories, Inc., No. 10-1150, ___ U.S. __ (S.Ct. March 20, 2012). Basically, the Supreme Court applied a long-standing principle that “laws of nature, natural phenomena, and abstract ideas” by themselves are not patentable.

The case could have important implications to the medical diagnostics and drug industry, but has potential effects on other industries as well. One of the main lessons from the case is that the content and manner in which claims are presented to the U.S. Patent and Trademark Office can be extremely important. The Court suggested that the extent to which patent claims provide practical assurance that a process is a genuine application of a law of nature rather than an effort to monopolize the discovery of a correlation, might be the determining factor for patentable subject matter in some process patents. That practical assurance may be available, following the Court’s suggestion, by inclusion of other steps in a claim that provides more specific and determinable application of the law of nature.

The claims at issue were from U.S. Patent Nos. 6,355,623 and 6,680,302, which were licensed to Prometheus Laboratories. An exemplary claim 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 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.

These steps were found by the Supreme Court insufficient to transform unpatentable natural correlations into patentable applications of those correlations.

The case arose when Mayo, which had purchased diagnostic test kits from Prometheus, decided to begin using and selling its own test having somewhat different levels of the metabolites. A lower court first hearing the dispute construed the claim language about “indicates a need to decrease” (or “increase”) as not limited to instances where a doctor actually decreases or increases the dosage level when the test indicates that an adjustment is advisable, and granted summary judgment to Mayo.

However the Federal Circuit reversed the lower court’s ruling, and asserted that the administering of the drug in the first step involved the transformation of the human body or of blood taken from the body. According to the CAFC, the claims satisfied the “machine-or-transformation” test set forth in the case of Bilski v. Kappos, 561 U.S. ___ (2010). But the “machine-or-transformation” test was not enough in this case. The Supreme Court disagreed and reversed the Federal Circuit with its ruling today.

The Supreme Court reaffirmed the long-standing principle that claims merely reciting laws of nature – in this case the relationships between concentrations of certain metabolites in the blood and the likelihood that a drug dosage will prove ineffective or cause harm – are not patentable. The Court suggested, however, that additional features in the claims that provide practical assurance that the processes are genuine applications of those laws of nature, rather than efforts to monopolize the discovery of the correlations, might make some process claims patentable subject matter.

The Court further suggested, by reference to an old English patent case from the 1840s, that if a claimed process includes not only a law of nature but also “unconventional steps” that confine the claims to a particular, useful application of the principle, it is much more likely to be found a patentable subject matter. Later cases will no doubt probe the boundaries of these suggestions.

Patent disputes centered around the question of patentable subject matter have been increasing in recent years, and several have now ended up at the Supreme Court. The results have not always been all that helpful to patent system stakeholders. Although the question of patentable subject matter is not a new area for judicial exploration, the explosion of cases suggests that further patent reforms may be necessary. As the Supreme Court said in concluding its opinion, “[We] must recognize the role of Congress in crafting more finely tailored rules where necessary.”

Click here to read the Supreme Court opinion.

For further information, contact any attorney in the IP Group at Morris, Manning & Martin, LLP.




This information is presented for educational purposes and is not intended to constitute legal advice. Opinions expressed are those of the author and not of Morris, Manning & Martin, LLP; see our disclaimer for more information. Contact John Harris for more information at