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Legal Affairs : Feb 1, 2011 (Vol. 31, No. 3)

Patenting Personalized Medicine Methods

Techniques Involving Physiological Processes Can Still Be Legally Protected
  • Courtenay C. Brinckerhoff

In 2010, the subject of “patent eligibility” made the headlines in legal circles. While much of the attention was originally focused on “business methods,” biotech and pharmaceutical methods got caught up in the debate with cases like Prometheus Laboratories, Inc. v. Mayo Collaborative Services (personalized medicine method claims, discussed here), Classen Immunotherapies, Inc. v. Biogen Idec (methods of evaluating and improving immunization schedules), and Association for Molecular Pathology v. U.S. PTO (isolated genes; methods of detecting specific genetic mutations).

In June, the Supreme Court issued its decision in Bilski v. Kappos, and held that the business method claims at issue did not satisfy the requirements for patent-eligibility set forth in 35 U.S.C. § 101. The Court did not provide much concrete guidance for applying the statute to other types of method claims, however, but vacated and remanded the Federal Circuit’s original Prometheus decision.

On remand, the Federal Circuit reconsidered the patent eligibility of Prometheus’ personalized medicine method claims in view of the Supreme Court Bilski decision, and again held that the claims qualify for patent protection under § 101. In so doing, the court followed a two-part analysis that may provide a framework for analyzing other method claims related to personalized medicine methods or diagnostic methods.

Prometheus’ claims relate to personalized methods of optimizing the dosing of specific drugs used to treat gastrointestinal autoimmune diseases. A representative claim reads:

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

(a) administering a drug providing 6-thioguanine 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 8 x 108 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 8 x 108 red blood cells indicates a need to decrease the amount of said drug subsequently administered to said subject.

(Not all claims require the administration step.)

Federal Circuit's Decision on Remand

The Federal Circuit began its analysis by noting that the Supreme Court has consistently construed § 101 broadly, in accord with Congressional intent, as reflected in the “expansive terms” used in the statute. The Federal Circuit nevertheless acknowledged that § 101 is not unlimited, because Supreme Court precedent provides three specific exceptions to § 101’s broad patent-eligibility principles: “laws of nature, physical phenomena, and abstract ideas.”

On this point, the Federal Circuit noted that Supreme Court precedent also holds that “an application of a law of nature or mathematical formula to a known structure or process may well be deserving of patent protection.”

The Federal Circuit characterized the issue on remand as “whether Prometheus’s asserted claims are drawn to a natural phenomenon, the patenting of which would entirely preempt its use…or…only to a particular application of that phenomenon,” which would be patent-eligible. The Federal Circuit considered the Supreme Court’s Bilski decision, and found that it “did not undermine our preemption analysis” and “did not disavow the machine-or-transformation test.” Thus, the court again looked at Prometheus’ claims through those lenses, undertaking a two-part analysis.

First, the court explained that the claimed methods “recite a patent-eligible application of naturally occurring correlations between metabolite levels and efficacy or toxicity, and thus do not wholly preempt all uses of the recited correlations.” In reaching this conclusion, the court noted, “[T]he claims recite specific treatment steps, not just the correlations themselves. And the steps involve a particular application of the natural correlations: the treatment of a specific disease by administering specific drugs and measuring specific metabolites.”

Second, the court confirmed that the claimed methods satisfy the machine-or-transformation test, which finds patent-eligibility under § 101 if at least one of the following two requirements are met:

(1) the process is tied to a particular machine or apparatus, or

(2) the process transforms a particular article into a different state or thing.

With regard to Prometheus’ main claims, the court expressed its belief that “administering a drug” always involves a transformation, because “[t]he drugs do not pass through the body untouched without affecting it” or without being metabolized. The court emphasized that the fact that the method “relies on natural processes does not disqualify the administering step from the realm of patentability.” The court reasoned that “[t]he transformation here . . . is the result of the physical administration of a drug to a subject to transform—i.e., treat—the subject, which is itself not a natural process.”

With regard to the “determining” claims that do not include an “administering” step, the court noted that “[s]ome form of manipulation, such as the high pressure liquid chromatography method specified in several of the asserted dependent claims…is necessary to extract the metabolites from a bodily sample and determine their concentration.” Thus, these claims satisfy the test as inherently involving a transformation.

The Federal Circuit rejected arguments that the “administering” and “determining” steps were mere “data gathering” steps or “insignificant extra-solution activity” that could not support patent-eligibility. To the contrary, the court found that the steps were “central to the purpose of the claims, which the court found to be “optimizing efficacy and reducing toxicity of treatment regimes.”

The court also made clear that the presence of the “mental steps” in the “wherein” clauses did not defeat patent-eligibility, because the claims must be evaluated as a whole. The court stated, “A subsequent mental step does not, by itself, negate the transformative nature of prior steps.” Because “[n]o claim in the Prometheus patents claims only mental steps” the prohibition against patenting mental steps per se did not impact Prometheus’s claims.

The Federal Circuit wrapped up its opinion with this query: “[W]hen asked the critical question, “What did the applicant invent?,”…the answer is a series of transformative steps that optimizes efficacy and reduces toxicity of a method of treatment for particular diseases using particular drugs.

This decision likely will be viewed as good news by innovators in the field of personalized medicine methods. It shows that method claims that rely on physiological processes (e.g., the metabolism of a drug into a measured metabolite) are not per se excluded from patent protection. The decision comes at a crucial time for the personalized medicine industry, when healthcare innovators, medical practitioners, and public health officials are promoting personalized medicine as offering the promise of more effective—and more cost-effective—treatments.

Still, by emphasizing the particularity and specificity of Prometheus’ claims, the court left itself room to reach different results in different cases, including Classen and Association for Molecular Pathology, both of which are pending before the Federal Circuit. Those seeking patents in this field probably will be advised to pursue claims that, like Prometheus’ claims, pass the “machine or transformation test” and include concrete language that focus the claims on “particular diseases” and/or “particular drugs,” to avoid being found to be impermissibly claiming an “abstract idea” or “natural phenomenon.”