Supreme Court Tackles §101 in Mayo v. Prometheus

Yesterday in Mayo Collaborative Services v. Prometheus Laboratories the Supreme Court addressed the question of patent eligible subject matter under 35 U.S.C. §101 for the first time since the Bilski decision last year.

Briefly, one of the claims in issue recites a method of optimizing treatment for an immune-mediated gastrointestinal disorder where a specific drug is administered to a patient, the level of a specific metabolite is determined in the patient’s blood, and a particular high metabolite level of a particular value indicates a need to reduce the dosage and a particular low metabolite level at a particular value indicates a need to increase the dosage. Another claim recites the same method, except excluding the administering step. Administering the drug was known in the art. Detection of the metabolites was known in the art. However, the correlation between specific metabolite levels and effectiveness or toxicity of the drug was not known.

Previously, the CAFC held that the administration step was transformative since it required changes within the patient’s body. The CAFC also held that the determining step was transformative because a transformation was required in order to detect the metabolite level in the blood. As such, the CAFC regarded both claims as complying with 35 U.S.C. §101. The CAFC stated that these claims recited not a law of nature, but an application of a law of nature. Like the Myriad Genetics case at the CAFC earlier this year, this oral hearing included attorneys for both sides, as well as a representative of the U.S. Government.

For additional commentary and summary of the Supreme Court’s oral argument see:
Supreme Court Hears Oral Argument in Mayo v. Prometheus


In the oral hearing, the attorneys for Mayo focused their arguments on the issue of preemption, citing to Flook and Diehr. Whereas Prometheus framed the scope of the claim limitation regarding the correlation between specific metabolite levels and effectiveness or toxicity as limited (the range between 230 pmol per 8×10 and 400 pmol per 8×10), Mayo characterized this as having virtually unlimited scope (the range from 400 pmol per 8×10 to infinity).

Thus, Mayo argued that the claims “preempt a whole field.” Justice Scalia pressed Mayo’s attorney on this, challenging him to draw a line where the cutoff for a correlation with toxicity would no longer create a preemption problem. The attorney explained that “doctors have to have the freedom to make their own judgments about these natural phenomena.” Justice Scalia was unimpressed by this, and stated that this is not a rule that could be easily applied.

After first stipulating that it was well established that a law of nature is not patent eligible but an application of a law of nature is patent eligible, Justice Breyer then introduced an interesting hypothetical. In Breyer’s hypothetical, a method is claimed where dosage of a drug is optimized by viewing discoloration of a finger—if too much drug is present, the finger become discolored. Mayo’s attorney argued that this would not be patent eligible because this simply adds an observation to a law of nature. My personal view on this hypothetical claim is that the step of administering the drug would be transformative, but the step of determining the color of the finger would not be transformative because is an observation which can be performed without any machine and without any transformation. Thus, my view is that if a claim only included the determining step, there would be no transformation of matter, and the claim would not recite patent eligible subject matter.

Justice Breyer, who later explicitly expressed second thoughts about his dissent in LabCorp, seemed uncertain about how to reconcile Flook and Diehr. Justice Breyer framed the question, as “how much has to be added” to a law of nature to make a process patent eligible? From here, the discussion strayed into a question of whether aspects of §102 and §103 should be imported into §101. Mayo argued that the recitation of a conventional (non-natural) step to a natural process was not sufficient to render a process patent eligible under §101.

Next, the discussion turned to whether the claims at issue were specific enough. Mayo argued that the claims can be construed to include optimizing treatment of dozens of diseases, and stated that the metabolite range for safe and effective dosage will vary among these diseases. Mayo also appeared to argue that the claims might be valid if instead of reciting that a metabolite level of more than 400 pmol per 8×10 “indicates a need to decrease the amount of said drug subsequently administered to said subject”, the claims recite that a metabolite level of more than 400 pmol per 8×10 indicated a need to, for example, reduce dosage by 20%. However, in my view, these comments are relevant to the enablement requirement in §112, not to §101.

Mayo also appeared to argue that the claims should have recited a subsequent treatment step of reducing dosage. However, while this may obviate any §101 question, such a claim may suffer from divided infringement problems. The CAFC will address this point soon at the en banc rehearing of Akamai and McKesson. Mayo ended their initial argument by again focusing on the issue of preemption.

U.S. Government

Next, the Solicitor General presented the viewpoint of the U.S. Government. The Government’s viewpoint is that the claims at issue comply with §101, but may be invalid in view of §102 and §103. The Government explained that many processes, such as igniting wood for heat, would be patent eligible in view of §101, since they involve the hand of man. However, processes like this could not actually be patented, since they would be anticipated by previous human activity.

The Justices also seemed interested in whether there was a greater burden on the USPTO or in litigation caused by rejecting a claim based on §101 vs. rejecting a claim based on §102 or §103. The Solicitor General explained that this was not a problem, since the USPTO reviews claims for §101, §102, §103 and §112 at the same time. From this line of questioning, it appears that the Court is thinking, as Judge Rader of the CAFC suggests, that §101 should be an initial coarse filter, followed by a §102 and §103 prior art analysis.

The Solicitor General’s time was then mostly consumed by questions from Justices Scalia and Breyer with respect to a new use of a known composition. The Justices seemed slightly confused about the differences between a composition of matter claim, a process claim, and a “use” claim (which is not patent eligible in the US).


Next, Prometheus presented their position. Surprisingly, the Justices did not interrupt the attorney for Prometheus nearly as much. Like the Government’s position, Prometheus urged the Court not to permit questions of novelty and obviousness to creep into §101. With respect to a hypothetical related to fertilizing plants, Prometheus argued that although a person 10,000 years ago could have received a patent for this, a person today could not. In other words, this subject matter passed through the coarse filter of §101, but in modern times would be anticipated and not patentable due to §102.

With respect to a hypothetical regarding a method of measuring energy, Prometheus referred to a claim in 1853’s O’Reilly v. Morse (also known as the Telegraph Patent Case), which recited a method of using electricity to write at a distance. Prometheus argued that this claim would have preempted future innovation, and thus was too abstract to be patent eligible. Prometheus then argued that their claims were unlike this, and did not recite a broad idea of correlating metabolite levels and treatment. Instead, they argued that the claims were applied to a specific class of drugs, specific metabolite levels and specific diseases. Further, Prometheus explained that although the claims recited a particular range of metabolite levels indicative of ideal treatment levels, this did not preempt another party from filing an improvement patent where the range was specified in greater detail for a particular disease.

As to the lack of an actual step of treatment, or re-administration of the drug, Prometheus skillfully argued that precedent permits the patenting of a process where the only output is information, using analogies to a method of detecting ore in the ground and a method of detecting the likely location and size of an earthquake.

Furthermore, Prometheus argued that the fact that others had performed the conventional steps of the claimed method (the drug administration and the metabolite detection) should not bar patent eligibility for a claim which recites those conventional parts plus a novel discovery. In other words, Prometheus argued that the patentees should not be penalized by the failure of others to come before them. Prometheus wrapped up their argument by stressing that in order to comply with §101, a process must be a “physical, hands-on process” and must not preempt all follow-on innovation.

Mayo’s rebuttal

Finally, Mayo provided their rebuttal remarks. Mayo argued that §101 should be a “robust test”, and that the claimed process is “entirely natural.” Mayo further argued that the metabolite range claimed was inaccurate, but that the public is “stuck with” this information for the life of the patent. Mayo concluded with general policy arguments regarding protection of the research process, patients and the health care industry.


In conclusion, this was a very interesting discussion, although I was surprised at how little Bilski was mentioned. Although the hearing did digress on some tangents, the Justices’ questioning was generally on point and indicative of the difficult questions a case like this presents. Surely, the Court will be thinking of the impact a decision might have on the healthcare industry, as well as the information technology industry. Also, Justices are no doubt aware of other pending cases which may find their way to the Supreme Court, such as AMP v. USPTO, Classen v. Biogen, and the divided infringement cases of McKesson and Akamai. I will leave the reader to reach their own conclusions, but my best guess is that the Court is leaning toward the position that §101 should be a coarse filter and that §102 and §103 would be more appropriate to challenge the validity of the claims in this case. We will learn the answer in the spring.

Transcript is available here:

Audio recording will be available here:


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Join the Discussion

2 comments so far.

  • [Avatar for SooraJ]
    January 1, 2012 01:43 am

    Sir I wanted to ask u this. it is true that law of nature is not eligible for patent. but at the same time what if a particular amount of drug is administered by analysing statistical data of a number of biomarkers on a patient’s body.?

  • [Avatar for Charanjit Sehgal]
    Charanjit Sehgal
    December 22, 2011 06:15 am

    It is a well known fact that level of metabolite after the administration of a drug is a yard stick about arriving at the optimum dosage for a perticular drug for a particular disease. Conversion of a drug molecule into a mretabolite is a natural phenomenon so any claim on this aspect is not patentable. But the process of analysis/determining a specific metabolite which can’t be common for all and accordingly a process for arriving at an optimum dosage for a specific drug is not a natural law but the application of natural law,therefore, comples 101. Furthermore, it does not bar patentability of othert future potential new molecules patents on these aspects and also new applications of existing molecules on these aspects. 102 and103 can be applied if anticipation of the same or similar metabolite not otherwise