Diagnostic Method Claim in the US

(By George Wu) Another important case concerning biotechnology was decided last year at the US Supreme Court: Mayo Collaborative Servs. v. Prometheus Laboratories, Inc., 132 S. Ct. 1289 (2012)

Prometheus Laboratories (“Prometheus”) had obtained a patent for a method of determining the optimal dosage of the drug thiopurine, which is used to treat auto-immune disorders.  The use of thiopurine in the treatment of disease was not a new discovery, but the use of the drug had been made difficult by the fact that thiopurine is metabolized at different rate in different people.  Accordingly, the same dosage could be too low to be efficacious in one patient, while too high and toxic in another patient.  Prometheus made the discovery that by assaying for the metabolites of thiopurine, the rate of metabolism could be determined and the dosage could be adjusted according to the patient.