The patent in question concerns the relationship between thiopurines, which are drugs used to treat gastrointestinal disorders, and metabolites in patients’ blood. The patent, owned by Prometheus Laboratories, covers a method said to help doctors find the dose that is large enough to work and small enough to cause no needless harm.
Richard P. Bress, a lawyer for Prometheus, conceded that his client had built on existing information.
“They were used together before we did them,” he said of thiopurines and metabolites, “but why were they used? They were used by people who were trying to come up with what we came up with,” which he said was “a new treatment method, a new way of calibrating the right dose for each individual patient based on their metabolism, and help seriously ill patients.”
Until the Prometheus method was available, Mr. Bress said, “doctors had no way to tailor for each individual based on their metabolism the right dosage of these powerful but potentially toxic drugs.”
After a unit of the Mayo Clinic developed its own test using slightly different correlations, Prometheus sued for patent infringement. Mayo countered that what Prometheus sought to protect was an abstract idea based on natural phenomena that was not eligible to be patented.
Stephen M. Shapiro, a lawyer for Mayo, told the justices that allowing Prometheus to patent its method would damage research processes that are “fundamental to American health and to the economy and the health care industry.”
The federal government urged the court to find a middle ground.
“Each party in this case has got a valid point,” said Donald B. Verrilli Jr., the solicitor general. “Mayo is correct that you can’t get a patent by tacking a mental step onto an utterly conventional process for administering drugs and testing their effects.”
Still, Mr. Verrilli said, the Prometheus method was eligible to be patented as an initial matter but could then probably be challenged as invalid because it was obvious and insufficiently novel.
Mr. Shapiro said that was the wrong approach, urging the justices to adopt a robust threshold test to protect the public domain. “It’s the critical test defining what’s in the storehouse of information for medical researchers to use,” Mr. Shapiro said of the initial test for patentable inventions.
Justice Ruth Bader Ginsburg seemed inclined to agree. “People need to know up front that this is not a patentable subject matter,” she said.
Chief Justice John G. Roberts Jr. explored the distinction by describing what he called “a great idea.”
“You take wood, you put it on a grate, you light it, and you get heat,” he said. “So I can get a patent for that?”
“No,” Mr. Verrilli responded. “It’s not novel, and it’s obvious.” But he seemed to suggest that creating heat with fire could meet the threshold test of patent eligibility.
All nine members of the court heard the case, Mayo Collaborative Services v. Prometheus Laboratories, No. 10-1150, but it was a close call. Prometheus waited until Tuesday to tell the court that it had been purchased by Nestlé in July. According to Justice Breyer’s most recent financial disclosure forms, his family owned stock in Nestlé, which would ordinarily require his disqualification.
A court spokeswoman said the stock belonged to Justice Breyer’s wife and that she sold it before Wednesday morning’s argument, allowing him to sit.