WASHINGTON (AP) -- With researchers looking more and more for ways to tailor drugs and tests to each patient's needs, the Supreme Court on Wednesday considered how far companies can go to protect their profits in the burgeoning "personal medicine" field.
The justices heard from lawyers from the Minnesota-based Mayo Clinic, which wants the court to throw out a patent held by Prometheus Laboratories, owned by Switzerland-based Nestle. Mayo argues the patent would keep its own medical test off the market, at the cost of better care for patients.
The patent in question covers a blood test that helps doctors determine the proper dosage for a drug, thiopurine, to treat gastrointestinal and non-gastrointestinal autoimmune illnesses.
The patent claims methods of administering thiopurine to a patient and then determining the levels of the drug or the drug's metabolites -- what's left after it breaks down in the body -- in the patient's red blood cells. That observation is used to adjust the amount of medicine needed for that patient.
The Mayo Clinic formerly used the Prometheus test, but its doctors announced in 2004 that they had come up with their own test and would put that one on the market. Prometheus sued to stop Mayo, but a federal judge invalidated their original patent.
Natural phenomenon and mental processes cannot be patented and the Prometheus test used both, the judge said. That decision was overturned by the U.S. Court of Appeals for the Federal Circuit, leading Mayo to appeal to the Supreme Court.
Personalized medicine is becoming big business in the United States, with companies trying to find the best way to use a person's genetic makeup to help tailor care and find the most effective individualized treatments for cancer and other illnesses.
"There's lots of investment to be protected," noted Justice Stephen Breyer, whose wife sold stock in Nestle on Wednesday morning to clear the way for him to hear the case.
Some of the justices raised questions about the Prometheus patent.
"It's not a treatment regimen," Justice Elena Kagan said. "All you have done is pointed out a set of facts that exist in the world and are claiming protection for something that anybody can try to make use of in any way, and you are saying, 'You have to pay us.'"
"The court has never suggested that there is an extra statutory limitation that prevents patents on developing useful information, even if they have a mental step at the end," Prometheus lawyer Richard P. Bress said.
The Obama administration has come down on Mayo's side in this argument. "You can't get a patent by tacking a mental step onto an utterly conventional process for administering drugs and testing their effects," Solicitor General Donald Verrilli told the justices.
Mayo lawyer Stephen M. Shapiro argued that Mayo's test would be more accurate than the one from Prometheus, but the patent is keeping them from bringing it to the market.
"You can't wipe out a whole field so no one else can have a competing test," Shapiro said. "The result for the public is that these numbers would be frozen for 20 years and a very serious person couldn't get a second opinion from Mayo Clinic, which uses different numbers."
Justices will rule next year.
The full court heard arguments in this case, including Breyer. His wife sold her Nestle stock Wednesday morning after the court was informed Tuesday that Prometheus had been purchased by the Nestle conglomerate earlier this summer.