• Medical Diagnosis Patents Survive Bilski
  • November 20, 2009 | Authors: Minh-Quan K. Pham; Charles R. Wolfe
  • Law Firm: Blank Rome LLP - Washington Office
  • Since the Federal Circuit decided In re Bilski, questions regarding the patentability of medical diagnostic claims under 35 U.S.C. § 101 have been raised. This issue, however, is not new as it was raised in LabCorp v. Metabolite Laboratories. Unfortunately, in that case, the Supreme Court dismissed the case without considering whether medical diagnostic claims are patentable under section 101 (this issue was raised at the Supreme Court, but was not decided below).

    The Federal Circuit has now decided this issue in favor of patentability for medical diagnostic claims. In Prometheus Laboratories, Inc. v. Mayo Collaborative Services, No. 2008-1403 (Fed. Cir. September 16, 2009), the representative claim at issue was:

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

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

    In ruling that the claim is not invalid under 35 U.S.C. § 101, the Federal Circuit reviewed the claims under the machine/transformation test of Bilski. According to the court, both steps (a) and (b) satisfy the transformation prong of the test. Specifically, with regard to step (a), the Court found that “[t]he transformation is of the human body following administration of a drug and the various chemical and physical changes of the drug’s metabolites that enable their concentrations to be determined.” The court reasoned that when the drug is administered the body “necessarily undergoes a transformation.”

    The court also found step (b) transformative because the levels of 6-TG must be determined through a transformation, “for those levels cannot be determined by mere inspection.” The court reasoned that:

    [s]ome form of manipulation, such as the high pressure liquid chromatography method specified in several of the asserted dependent claims or other modification of the substances to be measured, is necessary to extract the metabilites from a bodily sample and determine their concentration.

    Additionally, the Federal Circuit found both steps (a) and (b) to be “central to the purpose of the claims” and are not “merely data-gathering.” In doing so, the court informatively distinguished the case from In re Grams. In Grams, the claims recite a process that involves performing a clinical test and determining if an abnormality exists based on the data from the test. The court, however, found that Grams only claims an algorithm that does not involve “transformation of the tested individuals,” while the steps in Prometheus are part of “treatment regimes for various diseases using thiopurine drugs.” Here, it appears that the claims in Grams involve only an algorithm to any general clinical test and methods of correlating that general test data, while Prometheus involves a specific test for a specific drug/metabolite.

    Additionally, the court found that the “wherein” clauses of the claims are mental steps, but they do not render the claims unpatentable. Here, the court reasoned that the “subsequent mental step does not, by itself, negate the transformative nature” of steps (a) and (b), because the claims must be view as a whole. Here, even though the “wherein” clauses are the novel part of the claim, the machine/transformation test pertains to the claim as a whole, not just its novel part.

    Overall, it appears that medical diagnosis claims are safe from §101 challenges, for now (Mayo has filed a petition for certiorari with the Supreme Court). Because medical diagnostic claims tying the method to a machine are impractical (as doing so would eliminate diagnosis by, e.g., a physician), the claims must involve a transformative step. Fortunately, most medical diagnosis methods require assaying for the presence or levels of a specific biological marker or metabolite. That step is most likely transformative according to Prometheus, because it usually involves a chemical/biological assay to determine the presence or levels of the marker or metabolite. Thus, a medical diagnosis claim should contain at least the following steps:

    determining the levels or presence of a specific marker/metabolite; and

    diagnosing a specific condition/disease based on the levels or presence of the specific marker/ metabolite.

    It must be noted, however, that the steps should include a specific marker/metabolite and its corresponding condition/disease. A general algorithm for determining a general marker and general corresponding disease is not like to satisfy the transformation test as noted by the court in Grams.