Today, the Supreme Court granted Mayo’s petition for a writ of certiorari to review the Federal Circuit’s holding that Prometheus’s patent claims to clinical and diagnostic methods constitute patent-eligible subject matter.1 With this vote, the Supreme Court has waded again into the waters of patent-eligible subject matter in the wake of its decision in Bilski.2 Moreover, the grant of review signals that the Court is inclined to provide further guidance to the lower courts as they flesh out the implications of the Bilski ruling. Importantly, the ruling reopens the question whether method claims that may include a “transformation” tangential to the recited steps qualify as patent-eligible subject matter under Section 101 of the Patent Act. As numerous biotechnology patents claim methods similar to those at issue in Prometheus, the outcome of this case will have a broad impact on the validity of patents in the biotechnology sector.

The Prometheus claims at issue are directed to methods of determining the levels of certain drug metabolites in patients with autoimmune disorders and comparing those levels to threshold values that indicate the drug’s efficacy or toxicity. In a 2009 decision, the Federal Circuit reversed the district court’s grant of summary judgment to Mayo, and found the disputed claims patent eligible under the “machine-or-transformation” test.3 Immediately after its decision in Bilski, the Supreme Court granted Mayo’s previous petition for certiorari, vacated the Federal Circuit decision, and remanded the case for reconsideration in light of the Court’s Bilski decision.