Mayo Collaborative Services v. Prometheus Laboratories, Inc.
Mayo v. Prometheus, 566 U.S. 66 (2012), was a case decided by the Supreme Court of the United States that unanimously held that claims directed to a method of giving a drug to a patient, measuring metabolites of that drug, and with a known threshold for efficacy in mind, deciding whether to increase or decrease the dosage of the drug, were not patent-eligible subject matter.
Source: Wikipedia — Mayo Collaborative Services v. Prometheus Laboratories, Inc. (CC BY-SA 4.0)