On Remand, Federal Circuit (Once Again) Decides Prometheus v. Mayo in Favor of Patent Eligibility for Methods of Treatment and Diagnostic Tests

Today a panel of the Federal Circuit issued a decision in Prometheus v. Mayo, an important case involving the application of the patent eligibility doctrine to biotechnology, and more particularly molecular diagnostic testing and personalized medicine. I have discussed this case in numerous previous blog posts, see for example here.

Background
In a nutshell, the case involves claims directed towards methods for optimizing the amount of drug administered to a specific patient, an example of personalized medicine. The claims are limited to certain categories of thiopurine drugs used to treat immune-mediated gastrointestinal disorders such as Crohn's disease, the use of which is often accompanied by serious adverse side effects, including hepatotoxicity. Because different patients metabolize the drug differently, it had been difficult for doctors to ascertain the proper dosage, and some doctors had reportedly been hesitant to prescribe the drugs at all for fear of toxic side effects.

The challenged claims are directed towards methods that all comprise a step of determining the level of thiopurine drug metabolite in a patient sometime after administering the drug to the patient, and based on the result of that determination recognizing that the dosage of drug administered to the patient should be increased or reduced, i.e.,a determination that the level of drug metabolite exceeds a certain threshold would indicate that the dosage should be decreased, and vice versa. Many of the claims also explicitly recite a step of administering the drug to the patient.

A district court judge, in an opinion clearly influenced by Judge Breyer's provocative dissent in LabCorp, held the claims patent ineligible for allegedly wholly preempting a "natural phenomenon." In its analysis, the judge dismissed the steps of administering drug and determining drug metabolite level as mere "data-gathering steps," irrelevant to the patent eligibility of the claim.

The case was appealed to the Federal Circuit, but before the appeal was decided the Federal Circuit issued its en banc In re Bilski decision (Bilski I) which held the machine or transformation test to be the definitive test for patent eligibility of method claims.

On appeal the Federal Circuit panel reversed and held that the Prometheus claims satisfied applied the newly minted Bilski machine or transformation test. In particular, the panel held that the steps of administering drug to the patient and determining drug metabolite level were both inherently and independently sufficient to satisfy the transformation prong of the machine or transformation test. In contrast with the district court, which dismissed these steps as mere data-gathering, the Federal Circuit characterized the administering and determining steps as central to the purpose of the claim and thus relevant to the question of patent eligibility.

But shortly thereafter, in Bilski v. Kappos (Bilski II), the Supreme Court overturned Bilski I to the extent that it had characterized the machine or transformation test as the definitive test for patent eligibility, and reiterated that the sole and fundamental test for patent eligibility is whether the claim "patents" a fundamental principle, i.e., laws of nature, physical phenomena and abstract ideas. The Supreme Court then vacated the Federal Circuit's decision in Prometheus v. Mayo and remanded the case to the Federal Circuit to decide in a manner consistent with Bilski II.

Today's Post-Bilski II Prometheus Decision
Today's Federal Circuit decision on remand comes to the same conclusion as the first, reversing the district court and holding all of the challenged claims to be patent eligible. The court's analysis is also virtually identical to the original decision, focusing primarily on the transformative nature of the administering and determining steps.

It is important to bear in mind that while Bilski II rejected the notion that the machine or transformation test is the only test for patent eligibility of method claims, it did acknowledge that the machine or transformation test is in many instances highly probative of the fundamental inquiry. Significantly, the Supreme Court did not offer up any other alternative test for determining whether a claim "patents a fundamental principle." As noted by the en banc Federal Circuit in Bilski I, as a practical matter it can be extremely difficult to apply this fundamental test to actual claims, which is why the Federal Circuit tried to institute the use of a definitive machine or transformation test as a more objective and easier to administer proxy for the ultimate inquiry. As a practical matter of expedience, I have predicted that the courts and PTO will continue to rely heavily on the machine or transformation test post-Bilski II.

In today's decision, the Federal Circuit panel pointed out that under Bilski II the scope of patent eligible subject matter remains quite broad, and that while fundamental principles are not patent eligible "particular applications" of fundamental principles are. Applying this standard, the panel held that Prometheus' claims do not preempt the correlations between drug metabolite level and optimal dosage, but rather utilize them in "the treatment of a specific disease by administering specific drugs and measuring specific metabolites."

The panel also emphasized the continuing relevance of the machine or transformation test, pointing out that the Supreme Court had characterize it as a "useful and important clue, an investigative tool" for determining patent eligibility. It then came to the same conclusion as it did in its pre-Bilski II decision, finding that both the administering and determining steps were each inherently and independently sufficient to confer patent eligibility on the claims. In view of this determination, the panel found it unnecessary to address the question of whether the claims satisfy the machine prong of the test.

The panel emphasized that if the claims had not included a step of administering a drug or determining the level of drug metabolite, but had merely recited recognizing the correlation between drug metabolite level and the desirability of modifying the dosage (i.e., the "wherein" clauses of the claims), then the claims would have been patent ineligible for claiming nothing more than "mental steps." But by including a step of administering a drug and/or determining the level of drug metabolite, transformative steps which are "central to the purpose" of the method, the claim is rendered patent eligible.

In effect, Bilski II had essentially on effect on the outcome of the Prometheus appeal. Fortunately, the Supreme Court decided Bilski II in a manner allows a great deal of discretion for the Federal Circuit and lower courts. This panel of the Federal Circuit clearly sees the importance of permitting the patenting of diagnostic methods and methods of treating patients with drugs, and sought to maintain their patent eligiblity by emphatically establishing that method claims reciting a step of administering a specific class of drugs to a patient, or of performing a molecular diagnostic test of the patient, are patent eligible per se.

However, the panel is also emphatic that claims that could be potentially infringed by merely thinking about or recognizing a physiological correlation cannot be patented, a hypothetical scenario that some critics of gene patents and patents on diagnostic tests often point to.

The one aspect of the decision that I found less than entirely convincing was the panel's attempt to distinguish over the holding in In re Grams, a 1989 Federal Circuit decision. Grams was a case involving the patent eligibility of claims reciting methods that basically involved (1) performing a clinical diagnostic test on an individual patient, and (2) applying an algorithm to the data generated by the test in order to determine whether an abnormality exists, and possible causes of the abnormality. In Grams, the data-gathering steps were disregarded in the court's patent eligibility analysis, and the claims held patent ineligible for "in essence" claiming nothing more than a patent ineligible algorithm.

In a sense, the Grams claims are highly analogous to the Prometheus claims. The determining step in the Prometheus claims involves nothing more than performing a clinical diagnostic tests on individual patient, and the step of using the results to determine whether drug dosage should be altered is nothing more than a simple algorithm. According to the Prometheus panel, the distinction lies in the fact that in Grams the "essence" of the claimed process is the algorithm, and that the Gram patent "focused only on the algorithm rather than a clinical test." I'm not sure how convincing this distinction is, perhaps the panel could have been more straightforward and acknowledged the tension between Grams and Prometheus.

However, I have read the Grams decision and think a plausible distinction is that the Prometheus claims are limited to diagnostic tests for a limited number of specified of drug metabolites, while in Gram the claim appears to broadly encompass any of a host of clinical tests to which the algorithm could be applied. This suggests that if the Prometheus claims had been drafted more broadly to encompass any drug and drug metabolite, rather than being restricted to specific classes of thiopurine drugs, the claims could have been found patent ineligible. In effect, the distinction between the Grams and Prometheus claims is a matter of claim scope, something I think would be better addressed using the enablement requirement rather than patent eligibility, as I argued in the amicus brief I filed with Robert Cook-Deegan in the Myriad gene patent case.

Finally, what are the implications of today's Prometheus decision for the patent eligibility of the genetic diagnostic method claims at issue in the Myriad gene patent case (Association for Pathology v. US Patent and Trademark Office)? Today's decision does not alter my previous prediction, which is that the outcome will depend upon how the Federal Circuit interprets the scope of Myriad's patent claims. If the Federal Circuit adopts the ACLU's broad interpretation the claims (which is the interpretation the district court judge accepted for his analysis), pursuant to which the claims broadly cover the purely mental process of analyzing genetic information, then under Prometheus I believe the claims must be found patent ineligible. Alternatively, if the Federal Circuit adopts Myriad’s interpretation of its claims, under which the claims are limited to methods that involve physically isolating and analyzing DNA molecules, I think under Prometheus the claims should be found patent eligible by virtue of comprising a transformative step (highly analogous to the administering step in the Prometheus claims) central to the purpose of the claimed methods.