Staff Writer
On March 20, 2012, the U.S. Supreme Court unanimously held that Prometheus Laboratory Inc.’s (“Prometheus”) diagnostic process to determine the appropriate level of thiopurine drugs for a patient is not patentable. Thiopurine drugs are used to treat autoimmune diseases. Because each person metabolizes thiopurine at different rates, physicians struggle to determine an appropriate therapeutic dose for a particular patient. Doses that are too high will cause toxic side effects, while doses that are too low will not be therapeutically effective. Prometheus patented a test for determining the precise correlations between how a patient metabolizes thiopruine and what is the appropriate dose for that patient. Although Mayo Clinic Rochester and Mayo Collaborative Services (“Mayo”) had previously used Prometheus’ test, in 2004 it announced an intention to use and sell its own test, which would be similar to the Prometheus test, but with higher metabolite levels. Prometheus sued Mayo for patent infringement. Continue reading



