Mayo Clinic announced Wednesday that it had won a lengthy legal battle against Prometheus Laboratories Inc., based in California, with the Supreme Court unanimously agreeing with its argument that natural bodily responses to medical treatment are not patent eligible.

[The Associated Press described the ruling this way: ”a decision that could affect the burgeoning field of personalized medicine.”

[“The justices unanimously agreed that the patents held by the company — owned by Switzerland-based Nestle — were invalid because they were based on the laws of nature, which are unpatentable,” the AP added.]

Up until 2004, the Minnesota healthcare provider bought and used a blood test from Prometheusthat allowed doctors to decide the proper dosage for a drug called thiopurine, which is used to treat gastrointestinal maladies. But when Mayo researchers developed a test of their own, they stopped purchasing the test leading Prometheus to sue for patent infringement and to block Mayo from using its own test.

But the nine justices ruled that simply stating a natural process and asking that it be applied like Prometheus was demanding is not covered by U.S. patent law.

[“The question before us is whether the claims do significantly more than simply describe these natural relations,” said Justice Stephen Breyer, who wrote the opinion, the AP reported. “To put the matter more precisely, do the patent claims add enough to their statements of the correlations to allow the processes they describe to qualify as patent-eligible processes that apply natural law? We believe the answer to this question is no.”]

“Prometheus’ patents set forth laws of nature, namely, relationships between concentrations of certain metabolites in the blood and the likelihood that a dosage of athiopurine drug will prove ineffective or cause harm,” read the Supreme Court opinion. “Einstein, we assume, could not have patented his famous law by claiming a process consisting of simply telling linear accelerator operators to refer to the law to determine how much energy an amountof mass has produced (or vice versa).”

The opinion drew sharp responses from organizations that hailed the decision and decried it.

“Medical innovations that provide insight into natural human biology must remain freely accessible and widely disseminated. Blocking this information from physicians and researchers inhibits future discoveries,” said Dr.Robert M. Wah, chair of the American Medical Association, in a statement.

On the other side was BIO, a trade and lobby organization, which like the AMA had presented an amicus brief, but against Mayo’s argument and in favor of Prometheus’.

“We are surprised and disappointed in the Court’s decision, which disregarded the considered judgment of the Executive Branch experts and numerous amici such as BIO, who warned about the unintended consequences of attempting to use patent eligibility as a basis to strike down these patents for biomarker-based diagnostic methods,” saidHans Sauer,Deputy General Counsel for Intellectual Property, in a statement.

Read the Supreme Court ruling here.

(The Associated Press contributed to this report.)