In Endo Pharms v. Teva Pharms, the Fed. Cir. as embodied by Circuit Judges Wallach, Clevenger and Stoll reversed the DCt decision on patent eligibility for a method of treating pain in a renally impaired patient by providing controlled release oxymorphone, measuring creatinine clearance rates; and orally administering a lower dosage form depending on the creatinine clearance rate.  Citing Step 1 of Alice the Fed. Cir. asserted that it is not enough to merely identify a patent-ineligible concept underlying the claim; the court must determine whether that patent-ineligible concept is what the claim is ‘directed to.’ The Fed. Cir. found the claims legally indistinguishable from the claim in Vanda.  The Supreme Court has issued an order inviting the Solicitor General to file briefs to aid the high court in its decision on a petition for a writ of certiorari in the Vanda case. Mayo was distinguished based on the administration of a specific dose being based on the results of a kidney function test and was directed to more than just reciting a natural relationship.