Mayo Collaborative Servs. v. Prometheus Labs., Inc.: Supreme Court Rejects Diagnostic Process Claims as Unpatentable Laws of Nature


Mayo Collaborative Servs. v. Prometheus Labs., Inc., No. 10-1150 (U.S. Mar. 20, 2012) Slip Opinion

In a unanimous opinion, the Supreme Court reversed a ruling by the Court of Appeals for the Federal Circuit that had held Prometheus’ claimed invention, a process that helps doctors determine whether a given dosage of thiopurine drugs is too high or low, was patentable subject matter under the “machine or transformation test.” Mayo Collaborative Servs. v. Prometheus Labs., Inc., No. 10-1150, slip op. at 4, 7 (U.S. Mar. 20, 2012) (citing Prometheus Labs., Inc. v. Mayo Collaborative Servs., 581 F.3d 1336, 1345–47 (Fed. Cir. 2009)).

In an opinion by Justice Breyer, the Court held Prometheus’ claimed invention was unpatentable under 35 U.S.C. § 101, because it was fundamentally a law of nature. Id. at 24. In so holding, the court reasoned “the steps in the claimed processes (aside from the natural laws themselves) involve well-understood, routine, conventional activity previously engaged in by researchers in the field.” Id. at 4. The Court emphasized that just as a law of nature has long been held unpatentable, so too “is a process reciting a law of nature, unless that process has additional features that provide practical assurance that the process is more than a drafting effort designed to monopolize the law of nature itself.” Id. at 8–9.

SCOTUSblog provides a history of the case, briefs, and other relevant court documents. Patently-O breaks down the opinion in a section-by-section analysis. IPWatchdog criticizes the decision, admonishing that it will kill the medical diagnostics industry. The AMA praises the decision for invalidating patents that inhibit medical treatments. PharmExecBlog argues the decision may be a “harbinger” for the Myriad case now pending before the Court.

The invention concerns a scientific discovery involving the relationship between a patient’s response to a drug and its effectiveness. Scientists already understood that when a patient ingests thiopurine drugs, the level of certain metabolites that form in the bloodstream is correlated with whether a particular dosage is too high to be safe or too low to be effective. Id. at 4. Because every person metabolizes thiopurine differently, doctors had difficulty in determining the proper dosage. Id. The patents at issue embody researchers’ findings that identified the precise correlations between specified metabolite levels and likely harm or ineffectiveness. Id. at 5.

The Court held this correlation to be a law of nature. Id. at 8. Moreover, although all patents at some level apply laws of nature, id. at 2, these particular claims did not “add enough to their statements of the correlations to allow the process they describe to qualify as patent-eligible processes that apply natural laws.” Id. at 8. Rather, the Court held the claims simply tell doctors to: (1) measure the current level of the relevant metabolite using any means; (2) use laws of nature to determine the dosage’s toxicity or efficacy; and (3) reconsider the drug dosage in light of the natural law. Id. at 13. The effect of the claims is simply to tell doctors to apply a natural law somehow when treating their patients. Id. at 13.

The Federal Circuit below had reasoned that the invention fulfilled the “machine or transformation” test by transforming the human body by administering a drug and transformingthe blood by testing it to determine metabolite levels. Id. at 19. The Supreme Court rejected this application of the test, holding the first of these transformations irrelevant because the “administering” step merely serves to identify the audience interested in applying the natural law as doctors treating patients. 9, 19. Similarly, the second transformation in the “determining” step was insufficient because science could develop a non-invasive test in the future. Id.

The Court addressed policy rationales for the holding as well. Even though rewarding those who discover new laws of nature with patents might encourage their discovery, the Court warned that patents that are too broad could “inhibit further discovery by improperly tying up the future use of laws of nature. Id. at 16 –17. Even a narrow law of nature could inhibit research too much relative to the patentee’s contribution. Id. at 20. The Court noted that some medical experts have argued that claims covering the body’s natural processes would result in a thicket preventing physicians from providing effective medical care. Id. at 23.

This is the second recent Supreme Court decision addressing § 101 patentable subject matter issues, but it provides significantly more guidance than Bilski. The opinion relies primarily on the exclusion of “laws of nature” from patentability and a concern about overly broad patent claims, as opposed to Bilski’s “machine or transformation” test. A complete picture of § 101 doctrine is not likely to emerge until the Court decides Myriad, the gene patent case (addressing the patentability of human genes), which it is likely to remand in light of Prometheus.

Charlie Stiernberg is a 2L at Harvard Law School