The Federal Circuit's September 16, 2009 decision in Prometheus Laboratories, Inc. v. Mayo Collaborative Services, No. 2008-14-3 (Fed. Cir. Sept. 16, 2009) confirmed the patent eligibility of method claims relevant to medical diagnostics, therapeutic methods, and personalized medicine industries. The claims at issue included a step of determining drug metabolite levels in a patient after drug administration, and using the information to adjust drug dosage to maximize efficacy and avoid toxic side effects. In an opinion authored by Judge Lourie, the Federal Circuit applied the “machine-or-transformation” test announced in In re Bilski, 545 F.3d 943 (Fed. Cir. 2008) (en banc), cert. granted, 129 S. Ct. 2735 (June 1, 2009), and held that the claims satisfied the patentable subject matter requirement of 35 U.S.C. § 101 because the methods were transformative. The court therefore reversed the District Court for the Southern District of California's summary judgment ruling of invalidity

The Claims at Issue

A representative claim in this case recited:

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

(b) determining a level of 6-thioguanine in said subject [wherein levels below or above specific levels indicate a need to increase or decrease the dose of subsequent administrations]

Some other claims at issue did not recite the “administrating” step.

Prometheus, the licensee, marketed a diagnostic test using technology covered by the patents in suit. Prometheus sued Mayo for patent infringement of two patents after Mayo announced intent to use and sell a similar test.

The District Court Decision

The district court decision followed reasoning outlined in Justice Breyer's opinion dissenting from the dismissal of a grant of certiorari as improvidently granted in Laboratory Co. of American Holdings v. Metabolite Labs., Inc., 126 S.Ct. 2921 (2006). The district court determined that the “administering” and “determining” steps were merely necessary “data-gathering” steps that did not support patentability, and that the “wherein” clauses were mental steps that likewise could not be the basis of patentability. The court found that the “correlation” of metabolite levels and toxicity was a natural phenomenon and, therefore, not patentable under §101. The district court concluded that “[b]ecause the claims cover the correlations themselves, it follows that the claims ‘wholly pre-empt' the correlations.”

The Federal Circuit's Reversal

In reversing the district court, the Federal Circuit followed its own decision in Bilski, which addressed subject matter patentability under §101 in the context of business methods. In Bilski, the Federal Circuit applied the “machine or transformation” test for patent eligibility under 35 U.S.C. §101. Under this test, an invention is directed to patentable subject matter if: (1) it is tied to a particular machine or apparatus, or (2) it transforms a particular article into a different state or thing. The Bilski court explained, “transformation must be central to the purpose of the claimed process,” and that, in most cases, merely “gathering data would not constitute a transformation of any article.” The Bilski court warned that the machine or transformation must not consist merely of “insignificant extra-solution activity.”

Application of the Machine or Transformation Test

The Federal Circuit applied the “machine or transformation” test to the claims at issue in Prometheus and determined that the claimed methods met the transformation prong. (The Federal Circuit did not consider whether the claims might meet the machine prong). The Federal Circuit rejected the district court's determination that the claims merely recited “natural correlations and data-gathering steps.” To the contrary, the Federal Circuit noted that the “asserted claims are in effect claims to methods of treatment, which are always transformative when a defined group of drugs is administered to the body to ameliorate the effects of an undesired condition.”

The Federal Circuit explained that when claims recite administering drugs to a subject, transformation necessarily occurs because the “drugs do not pass through the body untouched without affecting it,” but rather transformation occurs as seen by “the effect on the body after metabolizing the artificially administered drugs.” Addressing the “natural phenomenon” arguments, the Federal Circuit stated, “Transformations operate by natural principles. The transformation here, however, is the result of the physical administration of a drug to a subject to transform — i.e., treat — the subject, which is itself not a natural process.”

With regard to claims that did not recite an “administrating” step, the Federal Circuit found that the “determining” step also was transformative and central to the claimed methods. Specifically, the Federal Circuit found that determining the metabolite levels “necessarily involves transformation” because such levels “cannot be determined by mere inspection.” For example, physical manipulation and measurement must occur (e.g., by high-pressure liquid chromatography (HPLC) or other methods that involve transforming bodily samples). The Federal Circuit concluded that the “determining” step was not merely data-gathering, but rather central to the purpose of the claims because “[m]easuring the [metabolite] levels . . . is what enables possible adjustments to . . . drug dosage.” The Federal Circuit concluded that, “[t]he determining step, by working a chemical and physical transformation on physical substances, likewise sufficiently confines the patent monopoly, as required by Bilski.”

The Claimed Methods Go Beyond Data-Gathering

Furthermore, the Federal Circuit determined that both the “administrating” and “determining” steps did not constitute “merely insignificant extrasolution activity” or “data-gathering,” but rather were significant aspects of a treatment protocol. The Federal Circuit distinguished the claims at issue from method claims that were essentially drawn to a mathematical algorithm “rather than any transformation of tested individuals.” The Federal Circuit also stated that Prometheus' claims were “not drawn merely to correlations between metabolite levels and toxicity or efficacy.”

Mental Steps Are Not Fatal to Patentability

The Federal Circuit emphasized that the presence of a mental step in a method claim does not necessarily render the claim unpatentable. The Federal Circuit agreed that the “wherein” clauses in Prometheus' claims recited “mental steps” and were not patentable on their own, but reinforced the principle that the patentability of a claim must be considered as a whole, with reference to other recited steps. As the Federal Circuit explained, a mental step does not “negate the transformative nature of prior steps.”

The Claimed Methods Do Not Impermissibly Preempt Natural Correlations

Along the same lines, the Federal Circuit found that the district court erred in concluding that the claims “wholly preempt use of correlations between metabolites and efficacy or toxicity.” The Federal Circuit emphasized that the claims were directed to “transformative methods of treatment, not correlations.” As stated by the Federal Circuit, “[t]he claims cover a particular application of natural processes to treat various diseases, but transformative steps utilizing natural processes are not unpatentable subject matter. Moreover, the claims do not preempt natural processes; they utilize them in a series of specific steps.”

Conclusion

While the Prometheus decision is immediate good news for many patentees in the medical diagnostics, therapeutic methods, and personalized medicine fields, some uncertainty remains because the decision is somewhat at odds with Justice Breyer's dissenting opinion in Metabolite. The Federal Circuit noted that Justice Breyer's opinion “is not controlling law,” and that the claims at issue were “different,” but the fact remains that the Federal Circuit here upheld claims that Justice Breyer might not have. The U.S. Supreme Court has granted certiorari in Bilski, and so may have an opportunity to address the patentability of diagnostic claims there, although the subject matter directly at issue in Bilski (a method of hedging the risk of bad weather through commodities trading) is wholly unrelated to medical fields. If the defendants in Prometheus seek Supreme Court review, it is possible that the Supreme Court will vacate the Federal Circuit's opinion and remand for reconsideration in view of Supreme Court's eventual opinion in Bilski. Companies working in diagnostic and personalized medical fields are advised to “stay tuned” and watch for the Supreme Court's Bilski decision.