The US Supreme Court has rejected two patents for a method of monitoring patient blood to determine drug dosage.
The Prometheus patents were challenged by the Mayo Clinic, which was sued for patent infringement by Prometheus on developing a version of the same test. The first local ruling invalidated the patents, before the Court of Appeals for the Federal Circuit ruled that the Prometheus method was indeed a patentable transformation.
The test involved measuring metabolite levels for patients receiving thiopurine drugs; however, methods to determine metabolite levels were already known and medical responses to these levels generally well-understood. The Supreme Court therefore ruled that the patent claims were invalid, since they referred to routine medical responses to natural phenomena
Comment: The decision has raised concerns among that other current and future personalised medicine applications could be at risk of losing their patent protection, with the effect of stifling further investment and development in the field. But in his ruling for the Supreme Court, Justice Stephen Breyer said rather that granting patents inappropriately for laws of nature might encourage discovery, but in the longer term inhibit innovation.