Patenting Medical Devices and Procedures


There is a great deal of valuable intellectual property associated with medical technology.  However the patent landscape is, in my opinion, unclear and unsettled.  Diagnostic procedures that utilize human biologic functions are denied patent protect because the procedures rely on “natural law”. I have tried to outline the problem using the actual wording of disputed patents and the words of the determining judges.  My goal is to allow the diligent reader an opportunity to evaluate the problem for themselves.

Statute Immunity for Medical Practioner

First, there is a little known Federal statute 35 U.S.C. §287(c) that provides patent law cannot block performance of a medical procedure. The statute states:

“a medical practitioner’sperformance of a medical activity that constitutes an infringement of an issued patent will not be held liable for damages and will not be enjoined from practicing the medical procedure claimed in the patent.”  

However I have never read in any source where this statute has been asserted to defend a patent infringement dispute.

Discussion of Patent Eligibility – Metabolic/DNA Factors

What constitutes patentable subject matter is very broad. However natural law, natural phenomena or abstract ideas are not patentable.  Although the courts have frequently invalidated patents as merely comprising an abstract idea, they have never felt compelled to define an abstract idea.  

As indicated, there are many court cases that have grappled with the issue of what mental steps, methods to organize human activity, collection or manipulation of data, or business procedures can achieve patentable subject matter.  This has created continued upset in the areas of software and business method patenting.

There are, in my opinion, three significant cases that pertain specifically to the patentability of medical procedures.  They are discussed below.  However, as a spoiler alert, the analysis of the cases do not provide a clear answer. (As an aside, the Mayo Clinic is a party in two of the three cases.  Perhaps this says something of their attitude toward competitor IP.)

Mayo v. Prometheus

First, there is the 2012 case of Mayo v. Prometheus.  The Supreme Court in Mayo re-asserted that “Laws of nature, natural phenomena, and abstract ideas are not patentable”.  The accepted rationale is that “they are the basic tools of scientific and technological work” that lie beyond the domain of patent protection.  Without this exception, there would be considerable danger that the grant of patents would “tie up” the use of such tools and thereby “inhibit future innovation premised upon them.”

At issue in Mayo v. Prometheus was Prometheus’s patent for use of a thiopurine drug in treatment of Crohn’s disease and ulcerative colitis. Administration of the drug was metabolized in the body to form metabolites detectable in the blood stream. It was known that certain levels were either too low or too high for effective treatment.  The patent claimed 


“(a) administering a drug providing 6-thioguanine to a subject having said immune-mediated gastro intestinal disorder; and

“(b) determining the level of 6-thioguanine in said subject having said immune-mediated gastro intestinal disorder, 

“wherein the level of 6-thioguanine less than about 230 pmolper 8×108 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 pmolper 8×108 red blood cells indicates a need to decrease the amount of said drug subsequently administered to said subject.”  

(Author’s Note: the Court’s interpretation of this claim is outlined below.)

Prometheus patented a procedure for monitoring blood levels to determine the efficacy of a drug treatment.  If the levels were too low, the patent procedure required additional administration of the drug.  Mayo Clinic purchased and utilized the tests.  However Mayo subsequently “developed” its own procedure wherein the threshold limits were somewhat different.  A patent infringement suit arose.  However it was determined that the difference utilized by Mayo in its new procedure were not patentably distinct.  Mayo was infringing upon Prometheus’s patent.  The dispute then turned upon whether the Prometheus patent was valid.  

The trial court determined that that the patents effectively claimed natural laws or natural phenomena—namely the correlations between thiopurine metabolite levels and the toxicity and efficacy of thiopurine drug dosages— and therefore the Prometheus patents were not patentable. 

The Court of Appeals for the Federal Circuit reversed and the matter was taken up by the Supreme Court.  

Supreme Court Fumble

The Supreme Court stated the issue to be decided was whether the 

“claims do significantly more than simply describe these natural relations.  To put the matter more precisely, *do the patent claims add enough to their statements of the correlations to allow the processes they describe to qualify as patent-eligible processes that apply natural laws?  We believe that the answer to this question is no.”

            *Author’s note:  This is a significant factor.

The court found that the claim included application of natural law or phenomena.  The court stated: 


The Court then went on to ask what was more to be decided:  

What else is there in the claims before us? The process that each claim recites tells doctors interested in the subject about the correlations that their searchers discovered.  In doing so, it recites an “administering” step, a “determining” step, and a “wherein” step.  These additional steps are not themselves natural laws but neither are they sufficient to transform the nature of the claim.

“First, the “administering” step simply refers to the relevant audience, namely doctors who treat patients with certain diseases with thiopurine drugs.  That audience is a pre-existing audience; doctors used thiopurine drugs to treat patients suffering from auto immune disorders long before anyone asserted these claims. In any event, the “prohibition against patenting abstract ideas ‘cannot be circumvented by attempting to limit the use of the formula to a particular technological environment.’”

“Second, the ‘wherein’ clauses simply tell a doctor about the relevant natural laws, at most adding a suggestion that he should take those laws into account when treating his patient.  That is to say, these clauses tell the relevant audience about the laws while trusting them to use those laws appropriately where they are relevant to their decision  making (rather like Einstein telling linear accelerator operators about his basic law and then trusting them to use it where relevant).”

“Third, the ‘determining’ step tells the doctor to determine the level of the relevant metabolites in the blood, through whatever process the doctor or the laboratory wishes to use. As the patents state, methods for determining metabolite levels were well known in the art.  Indeed, scientists routinely measured metabolites as part of their investigations into the relationships between metabolite levels and efficacy and toxicity of thiopurine compounds.  Thus, this step tells doctors to engage in well-understood, routine, conventional activity previously engaged in by scientists who work in the field. Purely ‘conventional or obvious’ ‘[pre]-solution activity’ is normally not sufficient to transform an unpatentable law of nature into a patent-eligible application of such a law.”

“To put the matter more succinctly, the claims inform a relevant audience about certain laws of nature; any additional steps consist of well­understood, routine, conventional activity already engaged in by the scientific community; and those steps, when viewed as a whole, add nothing significant beyond the sum of their parts taken separately.  For these reasons we believe that the steps are not sufficient to transform un­patentable natural correlations into patentable applications of those regularities.”


The patent was invalidated based upon the basis that the patent combined well know medical steps with mental activity.  The subject matter comprised an “abstract idea”.  An abstract idea is not patentable subject matter under 35 U.S.C. §101.  Note that the courts have consistently declined to provide a definition of what is an abstract idea.

AMP v. Myriad Genetics

The second case is AMP v. Myriad Geneticsdecided in 2013. The case pertained to whether DNA testing could be patented.  The Court determined that naturally occurring DNA segment is a product of nature and not patent eligible merely because it has been isolated.  It must remembered that nothing Myriad did altered the genetic information of the subject DNA.  

Myriad obtained several patents after discovering the precise location and sequence of the BRCA1 and BRCA2 genes, mutations of which can dramatically increase the risk of breast and ovarian cancer.  Myriad asserted that this was a discovery among approximately 8 million nucleotide pairs contained in a subpart of chromosome 17. This knowledge allowed Myriad to determine the gene’s nucleotide sequence, which, in turn, enable it to develop medical test useful for detecting mutations in the genes.  If valid, Myriad’s patents would give it the exclusive right to isolate an individual’s BRCA1 and BRCA2 genes and would give Myriad the exclusive right to synthetically create BRCA cDNA.  

Interestingly the Court of Appeals found (reluctantly?) the patents valid in light of the Supreme Court’s written statement of the Mayo case discussed extensively above.  The Court of Appeals held that the act of isolating the naturally occurring genes created an innovative product (an inventive act).  The separated BRCA gene was cleaved from a larger molecule and therefore became a separate free standing molecule or product.  The isolated DNA molecules became distinct from their natural existence.  

The Supreme Court disagreed for the reasons stated below.

A representative patent claim stated: 

“An isolated DNA coding for a BRCA1 polypeptide” which has “the amino acid sequence set forth in SEQ ID NO:2.”  

Note SEQ ID NO:2 was stated by the Court as constituting a list of 1,863 amino acids that the typical BRCA1 gene encodes.  The Court stated “(p)ut differently, claim 1 asserts a patent claim on the DNA code that tells a cell to produce the string of BRCA1 amino acids listed in SEQ ID NO:2.”

The Supreme Court held that a patent could not be claimed upon the naturally occurring DNA even when the DNA segment was isolated form its naturally occurring whole.  However, DNA that had been modified per the patent procedure could be patented.

The Supreme Court focused upon the fact that the cleaved molecule or DNA segment contained no new properties or structure than when the segment was attached to the longer (original) sequence.  It is worth noting that there were no new techniques utilized in separating or isolating the BRCA1 or BRCA2 segment.  There was therefore no basis to claim novel methodology.  Myriad was only claiming the isolated segment was a new “product”, i.e., composition of matter.  

Myriad patents gave it exclusive right to isolate the BRCA1 and BRCA2 gene (or any strand of 15 or more nucleotides with the genes) by breaking the covalent bonds that connect the DNA to the rest of the individual’s genome. The isolated gene was argued to become a patentable composition of matter.  However the Supreme Court, for the reasons stated above, invalidated the patent.

The Supreme Court also decided a non-medical device/procedure case Alice v. CLS Bank in 2015.  The Court again determined abstract idea comprising mental steps and well know business practices, enveloped into a computer program, could not be patented. The Alice decision has had significant spill over and been widely used by the USPTO to refuse to grant patent protection.

Athena v. Mayo

The third medical procedure/device case entitled Athena Diagnostics Inc. v. Mayo Collaborative Services, LLC was decided in early July of 2019.  One interesting aspect is that it is a decision by the Federal Circuit Court of Appeals sitting en banc, i.e., all 12 justices voted (versus the typical practice of cases decided by a three member panel).  Also unusual is the number of individual written opinions of the justices and the statements that some justices felt their hands were tied by Supreme Court precedent (discussed above).  (It is worth noting that the Court of Appeal of the Federal Circuit hears all appeals of patent disputes.  The only recourse after the Court of Appeals is the Supreme Court.  The Court of Appeals for the Federal Circuit is considered to possess high expertise on patent matters.)

Legal procedure aside, the issue was a patent owned by Athena for diagnosing a neurological disorder by detecting antibodies to a protein call muscle specific tyrosine kinase MuSK.  Mayo developed competing tests.  At issue was whether the Athena patent enforceable or whether it constituted an unpatentable abstract idea.

A representative claim (combination of independent claim 1 – not at issue- and dependent claim 7)

  1. A method for diagnosing neurotransmission or developmental disorders related to muscle specific tyrosine kinase (MuSK) in a mammal comprising the step of detecting in a bodily fluid of said mammal autoantibodies to an epitope of muscle specific tyrosine kinase (MuSK).

7.    A method according to claim 1, comprising contacting MuSK or an epitope or antigenic determinant thereof having a suitable label thereon, with said bodily fluid, immunoprecipitating any antibody/MuSK complex or antibody/MuSK epitope or antigenic determinant complex from said bodily fluid and monitoring for said label on any of said antibody/MuSK complex or antibody/MuSK epitope or antigen determinant complex wherein the presence of said label is indicative of said mammal is suffering from said neurotransmission or developmental disorder related to muscle specific tyrosine kinase (MuSK). 

Patenting After Supreme Court Fumble

The Court of Appeals reluctantly (and noisily) followed the decision of the Supreme Court of Mayo v. Prometheus(discussed above). 

As in the Mayo case, it was determined the claim covered a natural relationship between the presence of the MuSK complex and neurotransmission or developmental disorder.  The medical techniques to determine the existence of the naturally occurring MuSK complex were not novel or innovative.  

The panel majority also agreed with Mayo that “the steps of the claims drawn to ineligible subject matter, whether viewed individually or as an ordered combination, only require standard techniques to be applied in a standard way.”  In a lengthy footnote, the panel majority responded to a dissenting opinion by explaining that:

“The dissent states much that one can agree with from the standpoint of policy, and history, including that “the public interest is poorly served by adding disincentive to the development of new diagnostic methods.”  We would add further that, in our view, providing patent protection to novel and non-obvious diagnostic methods would promote the progress of science and useful arts.  But, whether or not we as individual judges might agree or not that these claims only recite a natural law, . . . the Supreme Court has effectively told us in Mayothat correlations between the presence of a biological material and a disease are laws of nature, and “[p]urely ‘conventional or obvious’ ‘[pre]-solution activity’ is normally not sufficient to transform an unpatentable law of nature into a patent-eligible application of such a law,” . . . .  Our precedent leaves no room for a different outcome here [citations omitted].”

Stated differently, the justices of the Court of Appeals are saying that finding a new diagnosis of a physical condition, regardless whether the novel technique depended upon a natural relationship, should be a patentable invention.  To use a lay person’s example, discovering an early method of diagnosing a cancer (treatable with early diagnosis) should be patentable, even though the method of diagnosis depends on finding an unusual but naturally occurring enzyme in the blood.  

This paper does not help the clinical researcher.  But hopefully it identifies a problem.  The “wise justices” of the Supreme Court have gotten it wrong.  

Finally, one justice of the Court of Appeals wrote:

“If I could write on a clean slate, I would write as an exception to patent eligibility, as respects natural laws, only claims directed to the natural law itself, e.g., E=mc2, F=ma, Boyle’s Law, Maxwell’s Equations, etc.  I would not exclude uses or detection of natural laws” (as patentable subject matter).

Note this corrective interpretation to the patentability of developments related to natural law, natural phenomena or abstract ideas does not utilize the question of the Supreme Court in Mayo, i.e., “do the patent claims add enough to their statements of the correlations ”with natural law “to allow the processes they describe to qualify as patent-eligible processes that apply natural laws?”  


Justice Kennedy acknowledged that patent practitioners loathed the Supreme Court taking up patent issues because “we will get it wrong”. That statement has proven true on several occasions. There is an effort within Congress to revise the text of 35 U.S.C. Section 101. However I am not optimistic that it will soon provide a remedy. Therefore, providing deserved protection for medially diagnostic procedures will be problematic.

©David McEwing, 2019