Diagnostic test can be patented, appeals court rules

Physicians worry that the ruling could hurt patient care if certain medical research is monopolized.

By Amy Lynn Sorrel — Posted Oct. 15, 2009

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In a decision that could have ramifications for medical research, a federal appeals court in September ruled that a diagnostic test for determining proper drug dosages to treat certain diseases is patentable under federal law.

Prometheus Laboratories Inc. sued Mayo Collaborative Services for infringing on its patents on the test, which measures metabolite levels in patients taking thiopurine drugs, then correlates those levels with the drugs' efficacy. Mayo developed a different testing method for detecting such effects and argued that Prometheus' patents were invalid because they covered naturally occurring phenomena, namely patients' drug metabolite levels.

In 2008, a federal trial agreed, finding that the patent violated federal laws barring the patentability of laws of nature, natural phenomena or abstract ideas.

But a panel of the U.S. Court of Appeals for the Federal Circuit, siding with Prometheus, said the patent was permissible because it involved a new application of a fundamental principle.

The applications "squarely fall within the realm of patentable subject matter because they transform an article into a different state or thing, and this transformation is central to the purpose of the claimed process," the court said in its ruling (link).

Physicians are concerned that allowing such broad patents will give companies a monopoly over the kind of medical research that should be shared to promote quality, cost-effective patient care. That's according to a friend-of-the-court brief filed in support of Mayo by the Litigation Center of the American Medical Association and State Medical Societies, the American College of Medical Genetics and several other medical organizations.

Mayo spokesman John Murphy said in a statement that Prometheus' patents "prohibit doctors from making their own observations of biological processes that occur naturally in patients, and using these observations to treat a variety of medical disorders." Mayo plans to appeal the ruling to the U.S. Supreme Court.

Prometheus and other biomedical research firms that weighed in on the case said the ruling would help incentivize companies to develop and commercialize innovative treatments that improve patient care.

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