Prometheus and Patentable Subject Matter Under 35 U.S.C. ' 101

Prometheus in the District Court

Prometheus first sued Mayo for infringement of two patents in the U.S. District Court for the Southern District of California. Prometheus Labs., Inc. v. Mayo Collaborative Services, et al., 2008 WL 878910 (S.D. Cal.) Prometheus asserted U.S. Patent Nos. 6,355,623 and 6,680,302. The claims are directed to “method[s] of optimizing therapeutic efficacy for treatment of an immune-mediated gastrointestinal disorder” and to “method[s] of optimizing therapeutic efficacy and reducing toxicity associated with treatment of an immune-mediated gastrointestinal disorder” by determining the level of two specific metabolites so that it “indicates a need” that an adjustment in drug dosage may be required at particular numeric levels. Id. at *1. Mayo had announced that it would begin using a test which utilized the same metabolites but with different numeric levels. Id. On summary judgment, the California court determined that Prometheus' claims were not directed to patentable subject material under ' 101, and granted summary judgment of invalidity. Id. at *14. The California court reasoned that the correlations between drug metabolite levels and therapeutic efficacy and toxicity were natural phenomena and thus unpatentable, citing Judge Stephen Breyer's dissent from the dismissal of certiorari in Laboratory Corporation of America Holdings v. Metabolite, Inc., 548 U.S. 124 (2006) (“Lab. Corp. Dissent”). The California court's analysis hinged on the determination that the method steps were “merely necessary data-gathering steps” combined with an additional mental step and thus were a recitation of natural phenomena. Id. at *5-7.