Summary of Mayo v. Prometheus Oral Argument

Guest Post by Jonas Anderson, Assistant Professor at American University Washington College of Law for Patently-O

Yesterday morning I attended the highly anticipated oral argument in Mayo v. Prometheus at the Supreme Court.  The case raises the question of whether a patent claim that covers correlations between blood tests and patient health is 'patentable' under 35 U.S.C. § 101. 

I assume most PatentlyO readers are familiar with this case, but will provide a very brief background before diving into today's argument.  Prometheus is the owner of a patent that covers a method of analyzing the effectiveness of thiopurine drugs for treating gastrointestinal disorders.  Claim 1 of the relevant patent reads as follows:

    (1) 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 8x10^8 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 8x10^8 red blood cells indicates a need to decrease the amount of said drug subsequently administered to said subject.

Prometheus offers a blood test which analyzes metabolite levels in patients.  Mayo sought to offer a competing blood test at a lower price.  Prometheus promptly sued Mayo for infringement.

I have divided my review into 7 topics.  The topics are ranked based on my impression of the importance that the justices appeared to give to each topic.  Although I have tried to transcribe the key statements made by the justices and advocates as accurately as possible, all quotations are approximate.

1.  The preemption question

The justices and the parties focused much of their discussion on the issue of preemption.  One of Mayo's principal arguments in its brief and at oral argument is that Prometheus's patent preempts the use of a law of nature — namely, the relationship between metabolite levels and patient health. 

Justice Kennedy began the preemption questioning by asking whether a system of measurements that continually monitor drug retention would be patentable.  Mayo's counsel responded that it would depend on the breadth of the claims.  "Claim specificity is key."  According to Mayo, if Prometheus's patent had provided competitors room to develop different, more accurate metabolite levels it may have passed the 101 test.  But, in this case Prometheus's patent preempted any reduction in dosage if a patient's metabolite levels were above 400 pmol.  In Mayo's view, "incidental" steps added to a natural phenomenon were insufficient to avoid preemption.  Thus, any patent consisting only of a natural phenomenon and "incidental steps" would be preempted under Mayo's test.

Justice Breyer, the author of the famous LabCorp dissent, focused nearly all of his questions on the issue of differentiating between a patentable application of a law of nature and an unpatentable law of nature.  He pressed both parties to identify a process by which the court could discern the difference.  Mayo's counsel first suggested that a preemption test could be used to ferret out unpatentable laws of nature.  Later, he suggested that Bilski suggests that courts can determine if the non-novel elements of a claim are "incidental."  "You're getting warmer," Justice Breyer quipped.

Justice Scalia interrupted the exchange and scoffed "I'm not comfortable with that.  It depends on how broad it is?  Is up to 700 [pmol]? Is that OK?  550?  830?  How are we supposed to apply that kind of rule?  It just seems to me not a patent rule that we could apply."  It seems fair to say that Scalia was not convinced by either party that a 101 standard based on preemption could be reliably applied by courts.

Despite Scalia's concerns, preemption seemed to carry the day — with both sides.  Justice Breyer continued the preemption line of questioning with Prometheus's counsel.  "What has to be added to a law of nature to make it a patentable process?  If you put too little to the answer to that question, I believe I can take things like e=mc2 and make them patentable, and if you put too much in you'll wreck your case."  Prometheus's counsel also advocated a preemption test, but its test would be much more limited than Mayo's.  Whereas Mayo would consider any natural phenomenon with "incidental" transformational steps as preempted subject matter, Prometheus would only find preemption when no applicative steps were added.  Prometheus repeatedly cited to the Morse telegraph case as a classic example of preemption under 101.

Of course, Prometheus's suggested application of the preemption test has an obvious problem: Bilski.  The patented hedging method in Bilski was not a naked claim to an abstract idea; the claim was limited by both industry and analysis techniques.  Prometheus's counsel acknowledged this difficulty, but argued that Bilski's abstract idea was merely coupled with other abstract ideas.

2.  The 'creep' of novelty and obviousness

Many of the Justices, but primarily the Chief Justice, expressed concern about the blurred relationship between novelty, non-obviousness and the 101 inquiry.  Chief Justice Roberts wanted to know what efficiencies would be gained, if any, by relying on Section 101 instead of obviousness or novelty to reject invalid patents.  Mayo made the case that 101 is a much more manageable and predictable doctrine than 102 or 103.  Prometheus countered by reference to the very case before the court — clearly Section 101 had not led to a quick resolution of this long-running case.

The Chief Justice asked Prometheus's counsel whether he was advocating for the elimination of a Section 101 limitation on patentability.  In response, counsel conceded that he was urging that courts rely on other patent doctrines in most cases, but that there would be some instances, such as the Morse case, in which 101 would be the proper vehicle for rejecting or invalidating a patent.

3.  The impact (or lack thereof) of LabCorp

In my view, one of the most surprising statements of the day came about as a result of Mayo's suggestion—in response to a question from Justice Scalia—that Justice Breyer's dissent in LabCorp could guide some of the analysis in this case.  Justice Breyer quickly interrupted and seemed to distance himself from his dissent.  Although he was convinced that the patent claims in the LabCorp case were merely directed to an observation of a law of nature, the dissenting opinion, he said, "lacked an explanation of why [the claims in that case were not] an application of the law of nature."

Throughout the argument, he was clearly wrestling with how much "extra" is needed in order to patent a newly discovered natural law.  If, as many have predicted, Justice Breyer pens part of the Prometheus decision, I expect that he will attempt to give some guidance to this most difficult question.

4.  The innovation question.

A healthy amount of discussion centered around the impact on innovation that a decision in this case will have.  Justice Breyer, who had been extremely skeptical of diagnostic method patents in his dissent in LabCorp, noted that discovering laws of nature can be an incredibly expensive process.  His search for a line between phenomenon and application seemed to center around balancing the incentive to discover new laws of nature with a desire to allow access to those laws to follow-on innovators. 

Mayo repeatedly urged the court to overturn the patent at issue by arguing that Promtheus could limit others from developing new, improved, and cheaper alternatives to their blood test and was therefore preemptive.  Mayo argued that if the claims incorrectly correlated metabolite levels and outcomes, "the public is stuck with the erroneous information."  In response, Prometheus stated that there are ways that follow-on innovators can improve on Prometheus's patent; namely, by acquiring an improvement patent or by challenging Prometheus's patent under Section 101's utility requirement.

Finally, as any good appellate attorney would, Mayo's counsel attempted to limit the perceived impact of a reversal.  When asked by Justice Sotomayor how many patents would be impacted by a ruling favoring Mayo, counsel responded "only a couple."

5.  The scope of Prometheus's patent

The newest Justices, Sotomayor and Kagan, directed nearly all of their questions to the scope of the patent claims at issue.  Although claim construction was no longer at issue, the Justices probed the extent to which Prometheus's patent foreclosed competitors.  Justice Kagan wanted to know what, in Mayo's opinion, Prometheus's patent attorney could have done to make their invention patent-eligible.  Mayo's counsel responded by saying that a claim with a more narrow range of relevant metabolite levels and a specified treatment protocol would satisfy 101.  Justice Kagan followed-up by asking whether "the difference is the scope of the ranges, or the treatment protocol."  "Both," Mayo responded.

Justice Kagan followed up with Prometheus.  When asked why the patent drafter had failed to include a therapeutic step (which Mayo conceded would have made the claim patent-eligible), Prometheus's counsel responded that it was unnecessary.  He pointed to numerous patents that merely claimed a method of gathering information: patents on identifying ore deposits (but not requiring removal); patents on navigating boats in fog (but not requiring redirecting the ship); patent to find leak in a water main (but not requiring repair).

6.  Prior decisions: are they helpful?

Justice Scalia seemed genuinely dismissive of the Court's precedents that have held that laws of nature (or natural phenomenon) are not patentable.  "Tell me why you can't patent nature?" he asked Mayo's counsel early in the proceeding.  "Doesn't any medical patent rely on natural processes?  Even if you invent a new drug, what that new drug does is natural.  Whatís the difference [from this case]?"  When Mayo's counsel responded that the specificity would be the key test for preemption, Justice Kennedy responded "I thought your answer to Justice Scalia would be...that [the claims here cover] the measurement of a result.  That's how I would have answered the question.  But that's obviously not the right way to do it."

In a related vein, Justice Breyer openly questioned whether the holdings in Flook and Diehr can be reconciled.  "If you look at the Court's cases, they seem to say Flook, one thing, and Diehr another thing."

7.  The transformation question

Almost no time was devoted to discussing whether the claims at issue meet the machine or transformation test. In fact, I can't recall hearing the words "Machine or Transformation" escape from the Justices.  Perhaps the Court is going to distance itself from the MOT test — or at least give courts another "clue."


Predicting the outcome of Supreme Court rulings in patent cases is a treacherous hobby.  If anything, the argument today revealed a Court troubled by the fact that both sides have urged an application of Section 101 that centers on preemption, but with little guidance on how to apply such a test.  While I would expect a ruling to have some mention of preemption, none of the justices seemed comfortable with either side's suggested application of such a test, while Justice Scalia was dismissive of such an idea. 

Perhaps most surprising was that the Court's most vocal critic of diagnostic patents, Justice Breyer, appeared to distance himself from LabCorp.  I get the feeling that he is still troubled with the idea of granting patent rights covering natural phenomenon, he is genuinely concerned with the impact of the Court's decision in this case on the medical innovation community. 


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