San Diego Based Prometheus Laboratories’ Patent Case Headed to Supreme Court

By Joseph Mandour on January 9, 2012

Patent InfringementsSan Diego – This month, the U.S. Supreme Court heard oral arguments for a lawsuit between Prometheus Laboratories and Mayo Collaborative Services. The Court’s decision could define the patentability of natural phenomena in the realm of diagnostic testing.

Prometheus alleged infringement of two patents used in a medical test that Mayo licensed, then independently offered based on its own statistical findings. The patents, U.S. Patent Numbers 6,680,302 and 6,355,623, encompass the correlation between metabolite levels and the efficacy and toxicity of thiopurine drugs. Prometheus claimed the exclusive license to methods for calibrating the correct dosage of thiopurine drugs, used for treating gastrointestinal and non-gastrointestinal autoimmune diseases.
Prometheus sued Mayo for patent infringement on June 15, 2004 in the U.S. District Court for the Southern District of California. The court granted Mayo’s motion for summary judgment on March 28, 2008. It held the claim’s first two steps of administering a drug to a subject and determining metabolite levels to be unpatentable as necessary data-gathering steps. The third step, the warning of a dosage adjustment was an unpatentable mental step. The district court also found the correlations to be unpatentable natural phenomena resulting from “a natural body process,” and that the inventors did not “invent” the claimed correlation.

Prometheus appealed the district court’s grant of summary judgment on May 16, 2008. The Court of Appeals reviewed the decision and held that the district court erred in finding the asserted claims to be drawn to non-statutory subject matter. It reversed the grant of summary judgment and upheld the patent in Prometheus because the preparatory steps of administering a drug and determining a metabolite level involved “transformations” of matter as the body’s natural reaction to ingestion of drugs. “[D]etermining metabolite levels in the clinical samples taken from patients” was transformative because “determining metabolite levels” included the extraction and measurement of metabolite concentrations.

In so holding, the Court of Appeals applied the Supreme Court’s machine-or-transformation test articulated in earlier cases and concluded that the disputed method fell squarely within the realm of patentable subject matter because its central purpose was to transform an article into a different state.

Mayo appealed the decision to the Supreme Court, which granted a petition for certiorari. However, the Supreme Court remanded the case to the Court of Appeals, stating that the machine-or-transformation test was not the sole test for what constitutes a process under §101, but “a useful and important clue, an investigative tool…” On remand, the Court of Appeals again held the asserted claims were statutory subject matter under §101, because the inventive nature of the claims recited “a particular application of the natural correlations: the treatment of a specific disease by administering specific drugs and measuring specific metabolites [,]” and did not preempt all uses of natural correlations.

Once again, Mayo appealed the decision to the Supreme Court, resulting in the present case.

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