Supreme Court Invalidates Process Claims in Prometheus

Executive Summary

In a unanimous opinion on March 20, 2012 in Mayo Collaborative Services v. Prometheus Laboratories., Inc., the United States Supreme Court invalidated Prometheus' process claims, which relate to a diagnostic test. The claims were deemed not eligible for patent protection because they effectively claimed underlying laws of nature.

The Court did not, however, close the door entirely on the possibility of patenting process claims using a natural law, holding that claims containing "inventive concepts" limitations could still be patentable, but clearer guidance on what is meant by "inventive concepts" will have to wait until the courts take further action.

The Court also took this moment to reiterate its finding in the Bilski decision that the "machine-or-transformation" test is only an "important and useful clue" to determining patentability, but would never "[trump] the 'law of nature' exclusion."

After the decision, the US Patent and Trademark Office (USPTO) sent examiners initial guidelines on how to apply the case. The examiners were instructed to reject claims directed to natural phenomena unless they include elements causing the claimed invention to amount to "significantly more" than a law of nature. The USPTO said that it is continuing to study the decision and would be developing more detailed guidelines in the future.


The Prometheus patent claims at issue examine relationships between concentrations of certain metabolites in the blood and the likely ineffectiveness or harmful effects of a dosage of the drug thiopurine. The blood level of the metabolites indicates a need to increase the amount of the drug administered if below a set level or a need to decrease the amount of the drug administered if above a set level. The claims recite (1) an "administering" step - instructing the administration of the drug to a patient; (2) a "determining" step - measuring the resulting metabolite levels in the patient's blood; and (3) a "wherein" step - describing the metabolite concentrations below which it is likely that the drug dosage is ineffective and above which there is a likelihood of harmful effects.

Prometheus sued Mayo for infringement. The district court held that the Prometheus claims were invalid because the claimed processes effectively claim natural laws or natural phenomena and, therefore, are not patentable. The United States Court of Appeals for the Federal Circuit (Federal Circuit) reversed, finding the claims to be patent eligible subject matter, applying the machine-or-transformation test. The Supreme Court granted a petition for certiorari and then remanded to the Federal Circuit for reconsideration in light of its opinion in Bilski v. Kappos which held that the machine-or-transformation test is not the sole test but rather a useful tool for determining patent eligibility. On remand, the Federal Circuit reaffirmed its earlier opinion.

Supreme Court Decision

In holding that Prometheus' claims are not patent eligible, the Court reasoned that because the laws of nature recited by Prometheus' claims are not themselves patentable, the claimed processes are not patentable without "additional features that provide practical assurance that the process is more than a drafting effort designed to monopolize the law of nature itself."

With respect to the three steps in the claims ("administering," "determining," and "wherein"), the Court held that the "administering" and "determining" steps are routine and conventional, and the "wherein" clause is merely suggestive. Therefore, none are sufficient to transform the essence of the claims, even if considered as an "ordered combination."

The Court also relied on its own precedent to warn against interpreting the patent statute in ways that make patent eligibility "depend simply on the draftsman's art". The Court concluded that any process that focuses on the use of a natural law should also "contain other elements or a combination of elements, sometimes referred to as an 'inventive concept,' sufficient to ensure that the patent in practice amounts to significantly more than a patent upon the natural law itself."

Although the Court did not articulate what constitutes an "inventive concept," it suggested that steps or a combination of steps that are not obvious, not already in use, or not purely conventional might constitute such an "inventive concept", thereby allowing for the future use of laws of nature.

Prometheus argued that its claims were patent eligible because they passed what the Court described as "the [Federal] Circuit's 'machine or transformation test'." In reply, the Court pointed out that "in stating that the 'machine-or-transformation' test is an 'important and useful clue' to patentability," it has "neither said nor implied that the test trumps the 'law of nature' exclusion."


The full significance of the Court's opinion will not be known until lower courts and the USPTO provide guidance as to how to apply this decision to specific types of process claims.

What is clear from the Court's decision is that claims should set forth one or more specific applications of a natural law, such that the claims do not cover all possible implementations of the natural law. At the same time, it is also clear that such claims should avoid having only specific applications that are merely routine or conventional steps.

While the Court has stated that claims must be limited to particular applications of natural laws, through the inclusion of "inventive concepts," the Court did not clearly articulate what constitutes "inventive concepts" sufficient to make patent-eligible a claim that embraces a natural law.

Encouragingly, though, the Court recognized "that too broad an interpretation of this exclusionary principle could eviscerate patent law. For all inventions at some level embody, use, reflect, rest upon, or apply laws of nature, natural phenomena, or abstract ideas." Notably, the Court observed that a "typical" patent for a "new drug or new way of using an existing drug" does not appear merely to encompass a natural law.

Importantly, in light of its decision in Prometheus, the Court today vacated the judgment in the Myriad Genetics case and remanded it to the Federal Circuit for further consideration.

The Court's decision may also serve as a basis for challenging existing patents as having claims that are not patent-eligible. Thus patent holders may wish to review existing patents to determine if the claims comport with this decision of the Court, and then take corrective action if necessary.