Patent Docs: District Court decision raises concerns regarding patent protection for diagnostic methods

The Supreme Court’s Mayo v. Prometheus decision in 2012 signaled renewed concern by the court regarding claims to diagnostic methods, including that patents on such methods could impede the ability of doctors to practice medicine. Whether justified or not, the court’s rationale has (as expected) begun to be translated into decisions at the trial court level. In particular, the decision by Judge Susan Illston of the Northern District of California in Ariosa Diagnostics v. Sequenom to grant summary judgment of invalidity against the patentee warrants consideration for its effects, if upheld, on the viability of diagnostic method patents.

The technology at issue is non-invasive prenatal diagnosis of sex determination, blood typing, other genetic disorders and detection of pre-eclampsia, using a simple blood test that reduces or eliminates the need for amniocentesis and chorionic villus sampling (which incur risks to both mother and child). The method claim recited detection (using DNA amplification and sequencing) of paternally derived fetal DNA (termed “cffDNA”) in maternal blood (as disclosed and claimed in U.S. Patent No. 6,258,540). The legal basis for the court’s grant of summary judgment of invalidity was based on the concept, from the Mayo case (but extending beyond the contours of that decision), that diagnostic method claims must do more than identify a law of nature and then direct that it be applied “without more” involving what the court identified (but did not define) as “an inventive concept.”

In applying this precedent, the court stated that it was undisputed that neither cffDNA nor the discovery of cffDNA in maternal plasma or serum is patentable, because the presence of cffDNA in maternal plasma or serum is a natural phenomenon. The judge then decided that the methods recited in the claims, being “routine, well-understood and conventional,” did not add “enough” to satisfy the requirements for patent eligibility set out in the Supreme Court’s Mayo decision.

The decision is worrisome because the patent does not claim as an invention the discovery of cffDNA in maternal plasma or serum, but rather methods for detecting it to provide a diagnosis. The methods claimed here differed from the methods at issue in the Mayo case, where all of the process steps in the claim had been practiced before by physicians (specifically, administering 6-thioguanine to Crohn’s disease patients and monitoring drug and metabolite levels in the blood) so that the only “inventive” part of the claim was the identification of the optimal therapeutic window for the drug. Here, because the presence of cffDNA in maternal blood and the ability to use it to make a fetal diagnosis of disease or disorder were unknown, it is difficult to see how the method when considered as a whole could be considered “routine, well-understood and conventional.” It seems the court misconstrued statements that methods for amplifying and sequencing DNA from blood plasma were well-known to mean that amplifying and sequencing this particular (unknown) cffDNA could be considered “routine, well-understood and conventional.”

The court also rejected a second distinction with the claims at issue in the Mayo case: that in that case, the claims encompassed all methods for detecting 6-thioguanine or its metabolites in blood, while here the method steps were limited to amplification and sequencing. In the face of evidence that alternative methods for providing a fetal diagnosis had been developed, the court asserted that the standard should be whether commercially viable alternatives were known at the time the patent was filed or, at the latest, had been granted. This raises the possibility that, should the court’s view prevail on appeal, the only patent-eligible method claim would be one that could be practiced without infringing at the time the invention was made. It is hard to discern any advantage to patenting (as opposed to holding new methods as trade secrets) under this standard, because it would provide no benefit if the claims recited a specific method that one of ordinary skill in the art would understand could be circumvented using another known method.

This case illustrates the uncertainty that comes from enunciating a standard that raises a court’s subjective opinion on patent eligibility to be dispositive. The court’s decision can be understood (but not defended) by an “inverted telescope” view of what the patentee gets from her “monopoly” versus what the public gets from disclosure, wherein an excessive focus on private benefits thwarts the benefits to the public; and second, the Goldilocks idea that a court’s role is to ensure the proper balance between too much and too little patenting. This case just demonstrates the consequences of deciding cases wherein judicial prejudices under the guise of law are used to decide what should and shouldn’t be patent eligible.

Fortunately, it is now on appeal before the Federal Circuit, which should rule before the end of the year.

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Kevin Noonan is a partner with the law firm McDonnell Boehnen Hulbert & Berghoff LLP and represents biotechnology and pharmaceutical companies on a myriad of issues. A former molecular biologist, he is also the founding author of the Patent Docs weblog, https://patentdocs.typepad.com/