Not So Drastic After All:

Federal Circuit Softens Impact

of Bilski on Medical Diagnostics

 

By Jakub Michna

 

A

lmost one year ago, the Federal Circuit shook the patent world with its In re Bilski decision. Bilski announced the machine-or-transformation test as the “definitive test” for the patent eligibility of method claims. 

Yet practitioners and academics have been clamoring that this definitive test creates many uncertainties. In Prometheus Laboratories, Inc. v. Mayo Collaborative Services, the Federal Circuit resolves at least one of those uncertainties and makes clear that medical diagnostic claims can be patent eligible.

Medical diagnostic are tests used, for example, to diagnose a patient’s condition or to determine a best treatment method. In order to broadly protect the inventive method, medical diagnostic patent claims typically include a measurement step (e.g., determining the amount of compound A in a subject’s body) followed by an inferential step (e.g., concluding that the subject has a particular disease based on the amount of compound A).

In this case, Prometheus’s claims were directed to a method of determining drug dosage for gastrointestinal disorders. The method required administering a drug to a subject. Once the drug was ingested, it broke down into a metabolite called 6-thioguanine (6-TG). The claim required determining the level of metabolite within the subject.

The last step of the claim required the inference that (a) a level of 6-TG less than a minimum value indicated a need to increase the dosage to a therapeutic level, or (b) that a level of 6-TG more than a maximum value pointed toward decreasing the dosage to a non-toxic level.

Before the Prometheus case, it was uncertain whether such medical diagnostic claims were patent eligible. Under the machine-or-transformation test, a claim must either be “tied to a particular machine or apparatus” or “transform an article into a different state or thing.” 

The problem with Prometheus’s claims and other such medical diagnostic claims is that they usually do not require any particular machine and they do not recite a physical or chemical transformation. Therefore, even though medical diagnostic claims appear technical in nature, it was uncertain whether they met the machine-or-transformation test.

When Prometheus asserted its medical diagnostic claims against Mayo, the trial judge in the Southern District of California struck down the claims as directed to ineligible subject matter. The district court reasoned that the claims were ineligible because they wholly preempted a natural phenomenon. 

Natural phenomena are one of the Supreme Court’s enumerated exceptions to patent eligibility. The district court explained that the inventors did not invent the correlation between 6-TG and therapeutic efficacy or toxicity. The correlation has always existed as a natural phenomenon and, therefore, could not be patented.

On appeal, the Federal Circuit overturned the district court’s decision, holding that the Prometheus claims “squarely fall within the realm of patentable subject matter because they ‘transform an article into a different state or thing.’” The Court explained that the claims did not preempt all uses of the natural phenomenon, but only those uses of the natural phenomenon that included the administering and determining steps.

The district court ruled that those steps were merely “necessary” data-gathering steps and, therefore, did not merit consideration. The Federal Circuit took a similar approach but came up with the opposite conclusion. The Court explained that the administering and determining steps were “integrally involved” in the method.

The Court found that administering the drug and determining the level of metabolite is what enables the adjustment of the dosage. Accordingly, because these steps were more than mere data-gathering, the Court relied on them to demonstrate that the claims were patent eligible.

Although the determining and administering steps did not recite a physical or chemical transformation, the Court explained that they “clearly” met the machine-or-transformation test, specifically the transformation prong of the test. The human body itself undergoes a transformation by reducing the administered drug into a metabolite. 

Mayo argued that the breakdown of the drug into a metabolite occurs according to a natural process which cannot be patented. The Court rebuffed that argument by pointing out that all transformations of matter follow natural processes. 

The Court ruled that the determining step also required a transformation because determining the level of metabolite required the transformation of a human sample.  The Court reasoned that, to determine the level of metabolite, a bodily sample must be drawn and the metabolite must be extracted from the sample: “At the end of the process, the human blood sample is no longer human blood; human tissue is no longer human tissue. That is clearly a transformation.”

An essential lesson of Prometheus is that a claim can meet the machine or transformation test even if a chemical or physical transformation is not explicitly recited within the claim. The question to ask is whether the claimed method requires a chemical or physical transformation. 

In Prometheus, the claims required a transformation because a drug cannot flow through the body “untouched” and because one cannot determine the amount of metabolite in the body “with mere inspection.” At some point, a chemical or physical transformation would have to happen.

The Prometheus decision may create some controversy at the Supreme Court.  The Supreme Court recently granted certiorari to review the machine-or-transformation test in the Bilski case, but some justices on the Supreme Court have already expressed their displeasure with medical diagnostic claims.

In Labcorp v. Metabolite (2006), three justices of the Supreme Court argued that the Court should have reviewed the case and struck down a medical diagnostic claim as ineligible subject matter. These justices believe medical diagnostic claims preempt natural correlations in the human body and, as a natural phenomena, are not patent eligible.

The patent claim at issue in Labcorp was eerily similar to Prometheus’s claims, requiring only two steps: “assaying a body fluid for an elevated level of total Homocysteine” and “correlating an elevated level of total homocysteine in said body fluid with a deficiency of cobalamin or folate.”

The issue was never decided because the other justices ruled to deny certiorari. The Federal Circuit’s inclusive interpretation of the transformation prong will certainly color the Supreme Court’s consideration of the Bilski v. Doll case, given that some justices have made up their minds about medical diagnostic claims.

In the meantime, the Federal Circuit has provided patent owners and applicants with a little more wiggle room. Method claims need not explicitly recite chemical or physical transformations to meet the transformation prong of the test. What is more important for purposes of patent eligibility is that, at some point, the claimed method actually perform a physical or chemical transformation.

But patent owners and applicants should not let their guard down, because the standard could completely change when the Supreme Court decides Bilski.