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Patentability of method of treating humans

In Prometheus Laboratories, Inc. v. Mayo Collaborative Services (Fed. Cir. 2008-1403, decided September 16, 2009), the Federal Circuit found that the asserted claims of the patents in suit meet the transformation prong of the machine-or-transformation test (see Bilski, 545 F.3d 961) and therefore are directed to statutory subject matter.

The two patents involved in the suit are U.S. Patents 6,355,623 (the ‘623 patent) and 6,680,302 (the ‘302 patent). They relate to a method of optimizing therapeutic efficacy for treatment of gastrointestinal and non-gastrointestinal autoimmune diseases using thiopurine drugs. Claim 1 of the ‘623 patent reads as follows:

1. A method of optimizing therapeutic efficacy for treatment of an immune-mediated gastrointestinal disorder, comprising:

     (a) administering a drug providing 6-thioguanine in said subject having said immune-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 8x108 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 400 pmol per 8x108 red blood cells indicates a need to decrease the amount of said drug subsequently administered to said subject.

Prometheus sued Mayo for infringement of the ‘623 patent and ‘302 patent at the district court. Mayo moved for a summary judgment of invalidity on the basis that the patents claim unpatentable subject matter under 35 USC 101. In particular, Mayo argued that the patents impermissibly claim natural phenomena and that the claims wholly preempt use of the natural phenomena. The district court found that the asserted claims fail to meet the machine or transformation prong of Bilski’s machine-or-transformation test because the administering and determining steps are merely data-gathering steps and the warning step (i.e., the wherein clauses) is only a mental step. The district court granted Mayo’s motion for summary judgment of invalidity under 35 USC 101.

On appeal, Prometheus argued that the asserted claims meet both prongs of the machine-or-transformation test. Prometheus argued that the patents rely on numerous machines to process the bodily sample in order to determine metabolite levels. Prometheus argued that administering of a drug transforms the biochemical makeup of the patient’s body. Prometheus argued that the determining step requires transformation of a bodily sample to determine the concentration levels of the created metabolites. Prometheus argued that the metabolite levels are transformed into a warning for a doctor to alter the dosage.

The Federal Circuit agreed with Prometheus that the asserted claims meet the transformation prong of the machine-or-transformation test. The Federal Circuit found that the asserted claims satisfied the transformation prong because the human body is transformed after the drug is administered. The Federal Circuit found that the determining step satisfied the transformation prong because the step necessarily involves transforming physical substances. The Federal Circuit found that the administering and determining steps are not merely data-gathering steps since the administering step involves providing a drug for the purposes of treating a disease and the determining step involves measuring the drug’s metabolite levels for the purposes of optimizing the treatment.

Other points made by the Federal Circuit include: (i) that the warning step (the wherein clauses) is not patent-eligible per se on its own because it is a mental step, (ii) that the presence of a mental step in a claim that contains other steps that are patent-eligible will not render the claim patent-ineligible under 35 USC 101, and (iii) that the asserted claims do not preempt a fundamental principle because they meet the machine-or-transformation test. The Federal Circuit did not consider whether the asserted claims meet the machine prong or not because the asserted claims need only satisfy one of the transformation and machine prongs to be valid under 35 USC 101.