In Athena Diagnostics, Inc. v. Mayo Collaborative Services, LLC, No. 2017-2508 (Fed. Cir. July 3, 2019), the Federal Circuit denied a patent owner’s petition for rehearing en banc after the patent owner’s asserted medical-diagnostic claims were held to be unpatentable laws of nature. The Court issued eight opinions (four concurrences and four dissents) that all supported eligibility of certain medical-diagnostic claims under 35 U.S.C. § 101, but most judges believed guidance from either the Supreme Court or Congress was needed to reverse precedent holding that such claims are unpatentable subject matter. The court noted that commercial laboratory tests require FDA approval, and the exclusivity period offered by patent protection for medical-diagnostic methods could encourage more inventors to invest the resources necessary to develop these tests and bring them to market. The decision highlights tension between current § 101 law and a need to foster innovation. Further discussion of the decision can be found on Finnegan’s Federal Circuit IP Blog.