Claims for Patent: 8,642,012

Summary for Patent: 8,642,012

Title:	Methods of treatment using ammonia-scavenging drugs
Abstract:	The invention provides a method for determining a dose and schedule and making dose adjustments of PBA prodrugs used to treat nitrogen retention states, or ammonia accumulation disorders, by measuring urinary excretion of phenylacetylglutamine and/or total urinary nitrogen. The invention provides methods to select an appropriate dosage of a PBA prodrug based on the patient's dietary protein intake, or based on previous treatments administered to the patient. The methods are applicable to selecting or modifying a dosing regimen for a subject receiving an orally administered ammonia scavenging drug.
Inventor(s):	Scharschmidt; Bruce (South San Francisco, CA)
Assignee:	Hyperion Therapeutics, Inc. (South San Francisco, CA)
Application Number:	12/350,111
Patent Litigation and PTAB cases:	See patent lawsuits and PTAB cases for patent 8,642,012
Patent Claims:	1. 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. 2. The method of claim 1, wherein target urinary PAGN output is determined as a ratio of the concentration of urinary PAGN to urinary creatinine. 3. The method of claim 1, wherein administration of the effective initial dosage of PAA prodrug produces a normal plasma ammonia level in the patient. 4. The method of claim 1, wherein the target PAGN output takes into account the patient's dietary protein intake. 5. The method of claim 1, wherein the target PAGN output takes into account the patient's residual urea synthesis capacity. 6. The method of claim 1, wherein the PAA prodrug is HPN-100. 7. The method of claim 1, wherein the pharmaceutically acceptable salt of PBA is sodium PBA. 8. A method of administering a phenylacetic acid (PAA) prodrug selected from glyceryl tri-[4-phenylbutyrate] (HPN-100) and phenylbutyric acid (PBA) or a pharmaceutically acceptable salt of PBA to a patient having a from urea cycle disorder comprising (a) administering a first dosage of the PAA prodrug; (b) determining urinary phenylacetyl glutamine (PAGN) excretion following administration of the first dosage of the PAA prodrug; (c) determining an effective dosage of the PAA prodrug based on the urinary PAGN excretion, wherein the effective dosage is based on a mean conversion of PAA prodrug to urinary PAGN of about 60%; and (d) administering the effective dosage to the patient. 9. The method of claim 8, wherein urinary PAGN excretion is determined as a ratio of the concentration of urinary PAGN to urinary creatinine. 10. The method of claim 8, wherein the pharmaceutically acceptable salt of PBA is sodium PBA. 11. The method of claim 8, wherein the PAA prodrug is HPN-100. 12. The method of claim 8, wherein administration of the effective dosage of PAA prodrug produces a normal plasma ammonia level in the patient.