By Jason Rantanen
Prometheus Laboratories, Inc. v. Mayo Collaborative Services (Fed. Cir. 2010)
Panel: Rader, Lourie (author), Bryson
Last Friday, the Federal Circuit released its second noteworthy post-Bilski decision (the first being Research Corp v. Microsoft). The opinion, Prometheus v. Mayo, issued following a grant-vacate-remand order from the Supreme Court instructing the CAFC to revisit its original decision in light of Bilski. Despite this procedural posture, however, the new opinion is quite similar to the old, arriving at the same conclusion through essentially the same reasoning.
Prometheus initially came to the Federal Circuit following a district court grant of summary judgment of invalidity under § 101 (lack of patentable subject matter). After the CAFC reversed the ruling of invalidity using its "machine-or-transformation" test, Mayo sought review by the Supreme Court. The Court granted certiorari, vacated the CAFC decision, and remanded for consideration in light of its Bilski opinion. Earlier Patently-O commentary includes a summary of the original Federal Circuit opinion and a discussion of the remand.
The patents-in-suit claim a method for determining whether a patient has received a therapeutically efficacious amount of drugs such as 6-mercaptopurine ("6-MP") and azthiopurine ("AZA"), which are used to treat inflammatory bowel diseases but can produce toxic side effects. In the human body, these drugs metabolize into 6-MP metabolites, including 6-methylmercaptopurine ("6-MMP") and 6-thioguanine ("6-TG"). By administering the drug, measuring the subject's levels of 6-MMP and 6-TG and comparing them to pre-determined levels, toxicity can be minimized and efficacy maximized.
Claim 1 of Patent No. 6,355,623 is representative:
1. 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 having said im-mune-mediated gastrointestinal disorder; and
(b) determining the level of 6-thioguanine in said subject having said immune-mediated gastrointestinal disorder,
wherein the level of 6-thioguanine less than about 230 pmol per 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 pmol per 8×108 red blood cells indicates a need to decrease the amount of said drug subsequently administered to said subject.
Although similar in most respects, some claims of the second patent-in-suit, No. 6,680,302, dispense with the "administering" step.
The Patents Do Not Claim a Physical Phenomena
On remand, the CAFC again rejected Mayo's argument that the '623 and '302 patents claim a "natural phenomenon." In seeking a judgment of invalidity under Section 101, Mayo contended (and the district court agreed) that the "administering" and "determining" steps are merely necessary data-gathering steps for the use of the correlations between 6-TG and 6-MMP and therapeutic efficacy or toxicity in patients. Because these correlations are simply natural phenomena, Mayo reasoned, they were unpatentable.
As before, the Federal Circuit disagreed, noting that Bilski provides a broad – although not unlimited – scope for patent protection, and “an application of a law of nature or mathematical formula to a known structure or process may well be deserving of patent protection.” Slip. Op. at 12, quoting Bilski, 130 S.Ct. at 3230. Furthermore, the court stated, neither the Supreme Court's order to vacate and remand the original Prometheus decision nor Bilski dictates a wholly different analysis or different result.
The crux of the CAFC's determination that the asserted claims recite a patent-eligible application of naturally occurring correlations between metabolite levels and efficacy or toxicity as opposed to the natural correlation itself rests on the specific treatment steps recited by the claims: the "administering" step and the "determining" step. "The inventive nature of the claimed methods stems not from preemption of all use of these natural processes, but from the application of a natural phenomenon in a series of steps comprising particular methods of treatment." Slip. Op. at 15-16.
In support of its conclusion, the court reiterated its earlier determination that the treatment methods in Prometheus's patents satisfy the "machine-or-transformation test. Although this is not the exclusive test, post-Bilski, it nevertheless provides important clues to subject matter patentabilty. In applying the machine-or-transformation framework, the court specifically rejected Mayo's argument that the disputed claims simply claim natural correlations and the associated data-gathering steps, broadly stating that the asserted claims are "claims to methods of treatment, which are always transformative when one of a defined group of drugs is administered to the body to ameliorate the effects of an undesired condition." Slip Op. at 17. Even leaving out the administration step does not make the claims unpatentable, as the CAFC also found the "determining" step to be transformative because it involves "[s]ome form of manipulation, such as the high pressure liquid chromatography method specified in several of the asserted dependent claims or some other modification of the substances to be measured, [which] is necessary to extract the metabolites from a bodily sample and determine their concentration." Id. at 18.
In reaching this conclusion, however, the court was forced to distinguish its earlier decision In re Grams, 888 F.2d 835 (Fed. Cir. 1989), which similarly claimed a process that involved "(1) performing a clinical test on individuals and (2) based on the data from that test, determining if an abnormality existed and determining possible causes of any abnormality by using an algorithm." Id. at 20. Unlike the claims in Grams – which the CAFC found unpatentable "because the tests were just to 'obtain data'" (Slip Op. at 20) – the claims of the Prometheus patents "require the performing of clinical tests on individuals that were transformative."
Mental Steps
In addition to its overarching analysis of the subject matter issue, the opinion also includes an interesting discussion of the use of mental steps in patent claims. Although the CAFC agreed that the final "wherein" clauses are mental steps, "A subsequent mental step does not, by itself, negate the transformative nature of prior steps. Thus, when viewed in the proper context, the final step of providing a warning based on the results of the prior steps does not detract from the patentability of Prometheus’s claimed methods as a whole." Slip Op. at 21. Because no claim in the Prometheus patents claims only mental steps, "contrary to Mayo’s assertions, a physician who only evaluates the result of the claimed methods, without carrying out the administering and/or determining steps that are present in all the claims, cannot infringe any claim that requires such steps." Id.
Additional Commentary
In addition to an extensive discussion about the decision in response to Dennis's post on Sunday, other sites commenting on the decision include:
- Patent Docs
- patents4life
- IP Watchdog
- Chris Holman's IP Blog
- Hal Weger of Foley has suggested that another grant of certiorari may be down the road, given the opinion's refusal to discuss a three-Justice dissent from the dismissal of certiorari in Lab. Corp., 548 U.S. 124, that was cited with approval by five Justices in two concurrences in Bilski.