Mayo Collaborative Servs. v. Prometheus Labs., Inc.: Supreme Court Hears Arguments on Patent-Eligibility of Medical Protocol Based on Correlations Between Blood Tests and Patient Health

Mayo Collaborative Servs. v. Prometheus Labs., Inc., No. 10-1150 (U.S. Dec. 7, 2011) Transcript of Oral Arguments

Mayo v. Prometheus returned to the Supreme Court after the Court of Appeals for the Federal Circuit again held that Prometheus’s method patents covered a particular application of a natural phenomenon, not the natural phenomenon itself, and were therefore valid. JOLT Digest covered the Federal Circuit’s initial ruling and its reaffirmation.

The Supreme Court heard arguments concerning whether a treatment that indicates a drug dosage based on correlations between metabolite levels in the patient’s blood and drug efficiency or toxicity is eligible for patent protection. Mayo argued that Prometheus’s patent was invalid because it covered a natural phenomenon: the correlation between metabolite levels, as revealed by a blood test, and patient health. Additionally,  Mayo claimed that the patent preempted all competing tests that would use metabolite levels (above a certain concentration that Prometheus’s patent covers) to adjust drug dosages. Transcript of Oral Argument at 8. Prometheus argued that their patent would not preempt competing tests because another party could file an improvement patent specifying a different range. Id. at 42. Prometheus said that its claims were patentable because it applied the conventional step of measuring metabolites in patients to the discovery of the natural correlation, and analogized its patents to patented processes that detect earthquakes, also a natural phenomenon.

Patently-O provides an overview of the case. Ars Technica criticized the lack of attention that the Court gave to the issue of whether medical patents are legal in general, analogizing the issue to overly-broad software patents. IPWatchdog has predicted that the Court will interpret § 101 as a “coarse filter” and leave Mayo to challenge Prometheus under § 102 and § 103. Published before the Court heard oral arguments, the Wall Street Journal argued that the Court should continue its longstanding policy of providing strong patent protection to encourage investment by finding Prometheus’s diagnostic test to be patentable subject matter. The Washington Post features a discussion of the main arguments.Prometheus is the sole and exclusive licensee of the two medical method patents at issue, which claim methods for determining the dosage of thiopurine drugs—used to treat certain autoimmune diseases—in order to optimize the therapeutic efficiency of the drugs while limiting their toxic side effects. The method typically includes two steps: administering the drug and determining the levels of drug metabolites in the patient. The levels of metabolites are then compared to standard metabolite levels and an optimal dosage is determined. Mayo had previously licensed Prometheus’s test, but later announced plans to create its own test, which would measure the same metabolites but use different standards for comparison. Prometheus then sued Mayo for patent infringement, and Mayo has not yet produced its own test.

The arguments before the Court centered on what section in the patent statute applied: the subject matter provision, 35 U.S.C. § 101, which has been interpreted not to include substantially unaltered natural phenomena, or § 102 and § 103, which include the patentability requirements of novelty and nonobviousness. Mayo argued that § 101 should be read as a high bar that excludes claims of natural phenomena unless there are significant alterations to the phenomena. A high bar, they argued, is the best result for the medical profession because § 101 is the only provision standing in the way of patenting natural formulas and correlations. Justice Breyer agreed that the issue is how much innovation must be added to an unpatentable law of nature to make the claim patentable. Transcript of Oral Argument at 13, 17. Likewise, Justice Scalia repeatedly stopped discussions on novelty and nonobviousness when counsel for Mayo strayed from arguing under § 101. Id. at 14.

Prometheus argued that their claims fell within the scope of patentable subject matter, and that Mayo could try to dispute their patents on grounds of utility if the metabolite ranges at issue were “completely wrong,” obvious, or not novel. Id. at 54–55. Siding with Prometheus, Solicitor General Verrilli argued that § 101 is a threshold test of whether there is a process, and the administration of a drug and measurement of its effects on the change in body chemistry satisfies this test. The real issue in this case, argued Verrilli, is whether Prometheus’s patents satisfied § 102 and § 103 for novelty and nonobviousness. Id. at 25–26.

As a matter of statutory interpretation, this decision will help to clarify the distinctions between § 101, § 102, and § 103 as applied to natural phenomena. If the Justices decide that these medical patents are valid, this decision could have broad implications for the medical profession by preventing institutions like Mayo Clinic from improving upon standards used in diagnostic tests and may subject the medical profession to increased liability for patent infringement.

Laura Fishwick is a 2L at Harvard Law School.