On Jun 18, 2018, the Federal Circuit in one-liner order affirmed PTAB’s decision that method of treatment patent of drug, RAVICTI® is valid.

US 8,642,012(Hyperion; Exp: Sep. 22, 2030) claims a method of treating a patient having a urea cycle disorder comprising (a) determining a target urinary phenylacetyl glutamine (PAGN) output (b) calculating an effective initial dosage of a phenylacetic acid (PAA) prodrug selected from glyceryl tri-[4-phenylbutyrate] (HPN-100) and phenylbutyric acid (PBA) or a pharmaceutically acceptable salt of PBA, wherein the effective dosage of PAA prodrug is calculated based on a mean conversion of PAA prodrug to urinary PAGN of about 60%; and (c) administering the effective initial dosage of PAA prodrug to the patient.

Previously, on April 29, 2015, Par Pharmaceutical, Inc. filed a Petition (IPR2015-01117) requesting an inter partes review of claims 1–12 of US 8,642,012. On Nov. 4, 2015, PTAB instituted trial & Lupin joined (IPR2016-00283) that petition. On Nov. 3, 2016, PTAB found that Par has failed to carry its burden of proving by a preponderance of the evidence that claims 1–12 would have been unpatentable over the prior art.