Medical Patent Fight Returns to High Court

     (CN) - The Supreme Court said Monday that it would take another look at a patent dispute that could let one medical lab patent a test for determining the proper dosage of drugs to treat autoimmune disease.
     A federal judge in California's Southern District had thrown out two patents belonging to Prometheus Laboratories, which the company was trying to enforce against the Mayo Clinic's medical laboratory division.
    Mayo has long used Prometheus' patented test for determining the correct dosage of thiopurine drugs used to treat autoimmune diseases. In 2005 it announced that it would begin selling its own dosage test, prompting an infringement lawsuit from Prometheus.
     Mayo argued that Prometheus could not patent its test, because it "claims natural phenomena."
     The district court agreed, ruling that the lab's method was not patentable because it is a patient's metabolite levels that warn a doctor of the drugs' efficacy, not the Prometheus method.
     But Prometheus argued that such interpretations of therapeutic and diagnostic methods would likely have a chilling effect on future medical discovery. It claimed that "adoption of the district court's reasoning would have the effect of eliminating all medical treatment and diagnostic patents, when future medical advances will depend on optimizing treatment based on genetic or other testing," the ruling states.
     The Washington D.C.-based appellate panel sided with Prometheus, finding that Prometheus' asserted medical treatment claims were drawn to nonstatutory subject matter under a patentability analysis called the machine-or-transformation test.
     The judges agreed with Prometheus that the method causes "physical transformations" to the human body, and as such it "cannot be unpatentable ... simply because they proceed according to natural laws or occur within the human body."
     Lourie cited the testimony of Prometheus' expert, Dr. Yves Théoret, who said, "At the end of the process, the human blood sample is no longer human blood; human tissue is no longer human tissue."
     Lourie wrote that the methods of treatment claimed in the patents "squarely fall within the realm of patentable subject matter because they 'transform an article into a different state or thing,' and this transformation is 'central to the purpose of the claimed process,'" citing the circuit's precedential ruling from one year ealrlier, In re Bilski.
     In that case, the circuit held that the machine-or-transformation test was the definitive test for determining the patentability of a process.
     The Supreme Court diminished the importance of that test, however, in 2010 with Bilski v. Kappos, which found that the some systems are too obtuse to be patented. The decision called the machine-or-transformation test "a useful and important clue," but not the sole test for determining the patent eligibility of process claims.
     Later that year when Mayo petitioned for review of the Prometheus decision, the high court vacated the Federal Circuit's ruling and directed the appellate judges to reconsider the case in light of Bilski.
     On remand, however, the Federal Circuit did not waver on its earlier finding.
     In its latest petition to the Supreme Court, Mayo asked the justices to answer whether a system is patentable if it covers observed correlations between blood test results and patient health, so that the claim effectively preempts all uses of the naturally occurring correlations, simply because well-known methods used to administer prescription drugs and test blood may involve "transformations" of body chemistry.