Within the next few weeks, the U.S. Supreme Court is expected to issue its highly anticipated Bilski decision, ruling on the extent to which business methods are susceptible to patent protection. But while Bilski itself relates to patent claims covering a business method, the Supreme Court’s ruling may well impact the bounds of protection available for medical diagnostics and even methods of medical treatment.

Patent-Eligibility of Process Claims The protection afforded by U.S. patent law is limited to particular types of subject matter. While the bounds of patent-eligible subject matter in the U.S. are set by statute, the interpretation of this statute has varied rather significantly over time as the courts render decisions addressing its meaning and breadth. Currently, a method or process is eligible for patent protection if it satisfies the so-called “machine-or-transformation” test: the method must (1) be tied to a particular machine or apparatus or (2) transform a particular article into a different state or thing, but cannot be a mere “data gathering step” or involve “insignificant extra-solution activity.” Accordingly, medical diagnostic or treatment methods are eligible for patent protection if they involve diagnostic or therapeutic steps that are “transformative” to the patient.
Recent Clarification Regarding Medical Technology In its recent Prometheus decision, the Court of Appeals for the Federal Circuit (the U.S. appeals court that reviews patent law issues) considered whether claims directed to methods for calibrating the proper dosage of thiopurine drugs, which are used for treating both gastrointestinal and non-gastrointestinal autoimmune diseases, define patent-eligible subject matter. Specifically, the court considered whether these claims satisfy the Bilski “machine-or-transformation” test.
First, the court explained that a step of “administering” a drug is transformative: “The 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 such claims are to methods of treatment, “which are always transformative when a defined group of drugs is administered to the body to ameliorate the effects of an undesired condition.”
Second, the court explained that a step of “determining” a metabolite level, which “cannot be determined by mere inspection,” is also transformative and “central to the claimed methods.” According to the court, “[s]ome form of manipulation . . . is necessary to extract the metabolites from a bodily sample and determine their concentration.” Indeed, the court cited testimony by Prometheus' expert that “at the end of the process, the human blood sample is no longer human blood; human tissue is no longer human tissue,” and stated that this is “clearly a transformation.”
Stay Tuned for Further Developments in 2010 Prometheus provides helpful guidance for assessing medical method claims under the Bilski “machine-or-transformation” test.  Under Prometheus, for example, claims drawn to methods of medical treatment that involve a transformation of the human body, assuming the transformation is central to the claimed method, are patent-eligible. In particular, claims directed to methods of treatment including administering a drug to treat an undesired condition are “always transformative,” and thus are patent-eligible.
Other questions, however, remain unanswered. Perhaps most notably, the patent-eligibility of purely diagnostic methods remains unclear.  Prometheus does not directly address whether a claim drawn to a method of diagnosing a condition, as opposed to treating a condition, would be patent eligible even assuming the claim recites a transformative step.  And, notably, while Prometheus emphasizes the importance of determining the “essence” of the claim to a patent-eligibility analysis, it provides little or no guidance on how to make such a determination.
The Supreme Court's Bilski decision is expected in the next few weeks. While the claims in Bilski are directed to business methods, it is quite possible that the Court’s decision may replace the “machine-or-transformation” test with some other legal framework. In addition, the Supreme Court has been asked to review the Prometheus decision. Stay tuned for further developments, as these cases will likely either provide greater clarity or create further uncertainty regarding whether certain types of medical method claims are eligible for protection under the U.S. patent laws.


Jason Kraus is a partner in the intellectual property group of Faegre & Benson in the Minneapolis office. Brian Oberst is a member of the Faegre & Benson intellectual property practice and a registered patent attorney.