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Supreme Court Strikes Down Patent for Lab Test that Determines Drug Doses

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May 3, 2012

A decision in March by the Supreme Court to disallow a patent on a laboratory test could impact any biomedical firms' decisions to develop and market diagnostic tests in the future, according to some attorneys who have followed the case. Alternately, however, these patent rulings may allow more universal patient access to testing in the medical management of certain diseases. Many view this as a success for the advancement of personalized medicine.

The nine justices of the Court voted unanimously in the case, Mayo Collaborative Services v. Prometheus Laboratories, Inc., Case No. 1150. The decision reversed an earlier ruling in favor of the patent by the U.S. Court of Appeals for the Federal Circuit.

The patent held by Prometheus Labs covered a blood test that identifies genetic variants of an enzyme needed to metabolize thiopurines, drugs used to treat autoimmune diseases and some forms of leukemia. Knowing the form of the enzyme present helps doctors determine the proper drug dosage. Doctors at the Mayo Clinic had previously used the Prometheus test, but developed their own in 2004 and began to market it. Prometheus sued, which started the multi-year court battle.

Justice Stephen Breyer, who wrote the opinion for the Supreme Court, said the patent issued to Prometheus Laboratories was invalid because it covered a law of nature—which is not patentable--not an innovative new process. "One must do more than simply state the law of nature while adding the words 'apply it,'" wrote Justice Breyer.

Attorneys who have followed the case say it's a critical one because personalized medicine—using an individual's genetic makeup to tailor their medical treatment—is emerging as an important business in the U.S. But companies may be quite reluctant to bring tests to market if they can't protect their patents and revenues earned selling the tests.

Prometheus Labs issued a statement that said in part: "Without the availability of patent protection, future healthcare will suffer as companies may opt out of new research and development. This decision will, in our view, encourage imitation, not innovation."

Ten days after ruling on the Prometheus Case, the Supreme Court, in another case, Association for Molecular Pathology v. Myriad Genetics, No. 11-725, ordered an appeals court to reconsider its decision to uphold patents held by Myriad Genetics on two genes, BRCA1 and BRCA2, associated with a high risk of breast and ovarian cancer. In addition to the patents on the BRCA genes, Myriad Genetics also developed a test that examines DNA of a woman for mutations that can indicate whether the woman is at risk of developing breast or ovarian cancer. The patent on the genes prevents other labs from doing similar tests. The lawsuit was brought by the American Civil Liberties Union and the Public Patent Foundation on behalf of patients, researchers and medical groups.

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NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used. To access online sources, copy and paste the URL into your browser.

Supreme Court Case: MAYO COLLABORATIVE SERVICES, DBA MAYO MEDICAL LABORATORIES, ET AL. v. PROMETHEUS LABORATORIES, INC. PDF available for download at through Accessed April 2012.

(March 21, 2012) "Top Court Patent Rejection Alarms the Biotech Industry". Wall Street Journal. Available online at through Accessed April 2012.

(March 20, 2012) Ed Silverman. Supreme Court Rejects Diagnositic Test Patents. Pharmalot. Available online through Accessed April 2012.

(March 22, 2012) Supreme Court Rules in Prometheus: Patent Claims Must Recite "Significantly More" than a Law of Nature. McDermott Will and Emery newsletter. Available online through Accessed April 2012.