Mayo prevails in patent case, but legal fight isn't over

Mayo Clinic has successfully invalidated the patent on a method of diagnosing a rare autoimmune disorder, handing the Minnesota health system a legal victory against one of the largest private lab companies in the U.S.

The Rochester-based academic medical center was sued by Athena Diagnostics, a subsidiary of New Jersey lab-industry giant Quest Diagnostics, over Mayo's decision to offer diagnostic tests for a disease called myasthenia gravis. MG is a chronic disorder that saps people's strength over the course of a day, often leaving them with drooping eyelids, leg weakness and difficulty swallowing and breathing.

Athena claimed in its federal lawsuit, filed in Massachusetts in 2015, that Mayo's tests infringed on Athena's exclusive right to use a patented method of diagnosing MG by detecting the chemical byproducts of a molecular interaction between a man-made chemical and a lab specimen taken from a person with the disease.

On Aug. 4, U.S. District Judge Indira Talwani ruled that Athena's proprietary test results are the product of a "law of nature," which cannot be patented, and the process didn't require "inventive techniques" that would have made it proprietary.

"Mayo Clinic and Mayo Medical Laboratories remain committed to providing high-quality comprehensive testing at an affordable price. Mayo will not comment further on the Athena/Quest litigation at this time," Mayo spokeswoman Gina Chiri-Osmond said via e-mail.

Emmett McMahon, a Minneapolis partner with Robins Kaplan, which is representing Athena, said the legal case is not over. "We disagree with the district court's decision and we plan on appealing," McMahon said Thursday.

The Athena ruling follows Mayo Clinic's legal victory at the U.S. Supreme Court in 2012 over another private lab company, Prometheus Laboratories, which is owned by Swiss foods giant Nestlé SA.

"The sky is falling!" the influential Virginia patent attorney Gene Quinn wrote on his blog, IPWatchdog.com, after the 2012 ruling. "An enormous number of patents will now have no enforceable claims. Hundreds of billions of dollars in corporate value has been erased."

This month's ruling in Athena v. Mayo relied in part on the legal precedents in Mayo's victory over Prometheus.

"Athena's patent is similar to the patent invalidated by the Supreme Court" in 2012, Judge Talwani wrote. In the 2012 case, "a man-made substance was administered to a person, and the byproduct of the metabolization of that man-made substance was observed. ... Here, a man-made substance (I-MuSK) is administered to a sample of bodily fluid, and the byproduct (I-MuSK autoantibodies) is observed."

Athena had patent rights to a process in which a synthetic version of the natural muscle-specific tyrosine kinase (MuSK) neuroreceptor was mixed with a biological sample from a patient suspected of having MG. If the patient has a specific form of the disease, the synthetic I-MuSK will leave easily identifiable radioactive traces on antibodies in the sample, thus diagnosing the disease.

Athena's lawsuit says that medical practitioners with Mayo ordered Athena's lab test sometime before May 19, 2015, and that after that date, the health system changed its policy and decided it would not purchase Athena's test. Around the same time, Athena said, Mayo developed its own lab tests to diagnose MG, violating the patent and causing Athena to lose profits on every MG test that Mayo runs.

Talwani ruled that Athena's patent did not cover the creation of the synthetic I-MuSK used in the test, but rather the application of I-MuSK to the sample, which is a chemical interaction governed by the laws of nature. Although special techniques have to be used to identify antibodies in the sample, Talwani agreed with Mayo that the process draws on widely understood concepts in laboratory medicine that cannot be patented.

In an interview Thursday, Quinn said the courts are misinterpreting patent law when it comes to proprietary lab tests, which may undermine investor confidence in funding new tests.

"It's gotten harder and harder to get these patents and keep them. And that should be a concern for everyone," Quinn said. "Because if you can't diagnose, then you can't treat."