Prometheus v. Mayo: Supreme Court decides that diagnostic methods are not patentable subject matter

May 01, 2012

The Supreme Court in the case of Mayo Collaborative Servs. v. Prometheus Labs., Inc., 2012 U.S. LEXIS 2316 (U.S. 2012), decided that diagnostic method claims that solely rely on a natural law are not patentable subject matter. The Court held that because the natural laws recited in the Prometheus patent claims are not themselves patentable, the claimed processes are not patentable unless they have additional features that provide practical assurances that the claims are a genuine application of the law rather than drafting efforts to monopolize the correlations. The Court also held these patent claims tie up the use of natural laws, the basic tools of scientific and technological work, resulting in inhibition of innovation.

The Court’s analysis begins with the recognition that natural laws are an exception to patentable subject matter and that too broad an application of this exception can eviscerate patent law. The Court goes on to discuss the circumstances that transform such unpatentable subject matter into a patent eligible practical application of such a law. Looking to case law precedents concerned with algorithms, such as Flook1 and Benson2, the Court finds a requirement for an “inventive concept” that shows that the claims include something beyond the natural law and do not rely on limiting the use to a particular technological environment or add insignificant post solution activity.

The claims at issue in the Prometheus case are directed to a method of optimizing therapeutic efficacy of a drug and include the steps of administering the drug, determining the level of metabolite of the drug, and increasing or decreasing the dosage on the drug based on the levels of the metabolite. Finding that the claims set forth a law of nature because the relationship between concentrations of metabolites and toxicity of the drug is based on natural processes in the body, the Court then looked at each step of the claims to see if they were sufficient to transform the nature of the claim.

This case turns on the interpretation of the claims. The Court found that the claims failed the “machine or transformation” test because the transformations relied on by the Federal Circuit in applying the test were found to either be irrelevant or not required by the claims. The Court characterizes the administering step as referring to physicians as the relevant audience and an attempt to limit the use of the formula to a particular technological environment. The Court concludes that any transformation due to administering is therefore irrelevant. The determining step was viewed as conventional obvious activity, and therefore, was nothing more than insignificant post solution activity not requiring any specific transformation. The “wherein” clause was interpreted as merely a suggestion that the doctor take into account the natural law when treating the patient. Analyzing the combination of the steps, the Court found that the steps do not add anything to transform patent ineligible subject matter to patent eligibility as they simply tell doctors to gather data from which they may draw an inference about the correlations.

Finally, the Court found that the claims at issue preempt use of basic science and technological tools and inhibit innovation. The Court points to Amicus briefs of several medical associations including the American Medical Association, the American College of Medical Genetics, and the American Hospital Association for the proposition that patents in this area will create a thicket of rights over critical information needed for patient care. The Court defers to Congress to determine if policy dictates that increased protection of diagnostic method claims is desirable.

The Court gives guidance as to how claims to diagnostic method claims that include a natural law could include steps that transform the natural law to patent eligible subject matter. By highlighting the Diehr3 case as an example of patent claims that achieve such a transformation, the Court suggests that the steps could include how the variables were selected, details of the chemical processes at work, and means for adjusting the limits as a result of the chemical processes. The additional steps should be more than conventional well known processes.

In summary, in the Prometheus v. Mayo case, the Supreme Court found that a diagnostic method claim that solely relies on a natural law to be patent ineligible. The Court found the claims failed the machine or transformation test because the transformations that occur as a result of the steps are either irrelevant or not required by the claims. Analysis of the claims in view of legal precedents shows the claims did not have additional features that transform the claims into patent eligible subject matter. Given this guidance, clients should review their existing portfolios to determine if the claims in pending cases should be changed or if issued cases should undergo reissue.



1Parker v. Flook, 437 U.S. 584 (1978).
2Gottschalk v. Benson, 409 U.S. 63 (1972).
3Diamond v. Diehr, 450 U.S. 175 (1981).