Study of Glycerol Phenylbutyrate & Sodium Phenylbutyrate in Phenylbutyrate Naïve Patients With Urea Cycle Disorders (UCDs)

Amgen

Status and phase: Completed; Phase 4

Conditions: Urea Cycle Disorder

Treatments: Drug: RAVICTI; Drug: NaPBA

Study type: Interventional

Funder types: Industry

Identifiers

NCT03335488

2015-000075-27 (EudraCT Number)

HPN-100-021

Details and patient eligibility

About

This is a randomized, controlled, open-label parallel arm study to assess the safety, tolerability, pharmacokinetics and ammonia control, of RAVICTI® as compared to Sodium phenylbutyrate (NaPBA) in urea cycle disorder subjects not currently or previously chronically treated with phenylacetic acid (phenylacetate; PAA) prodrugs. The study design will include: 1) Baseline Period; 2) Initial Treatment Period; 3) a RAVICTI only Transition Period 4) a RAVICTI only Maintenance Period; and 5) a RAVICTI only Safety Extension Period. The study will run for approximately 25 weeks.

Full description

Study acquired from Horizon in 2024.

Enrollment: 16 patients

Sex: All

Ages: Under 99 years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Signed informed consent given by the subject or the subject's parent/legal guardian for those under 18 years of age or the age of consent by local regulation.

• Male and female subjects with a suspected or confirmed UCD diagnosis of any subtype, except n-acetylglutamate synthetase (NAGS) deficiency.

• Suspected diagnosis is defined as having experienced a hyperammonemic crisis (HAC) or a documented high ammonia of >=100 µmol/L

• Confirmed diagnosis is determined via enzymatic, biochemical, or genetic testing.

  • Requires nitrogen-binding agents according to the judgment of the Investigator
  • Birth and older.
  • All females of childbearing potential and all sexually active males must agree to use an acceptable method of contraception from signing the informed consent throughout the study and for 30 days after the last dose of study drug. Acceptable forms of contraception are (oral, injected, implanted or transdermal), tubal ligation, intrauterine device, hysterectomy, vasectomy, or double barrier methods. Abstinence is an acceptable form of birth control, though appropriate contraception must be used if the subject becomes sexually active.

Exclusion criteria

• Subject has received chronic treatment with an oral phenylbutyrate (RAVICTI, NaPBA, Pheburane, or other) longer than 14 consecutive days within one year prior to enrollment.

• Temporary use of NaPBA for acute management of a hyperammonemic crisis in the past is acceptable.

  • Any concomitant illness (e.g., malabsorption or clinically significant liver or bowel disease) which would preclude the subject's safe participation, as judged by the Investigator.
  • Has undergone liver transplantation, including hepatocellular transplant.
  • Subjects on sodium benzoate (NaBz) at Baseline will be excluded if they are viewed by the Investigator as being unable to undergo NaBz transition to a PAA prodrug during the Initial Treatment Period.
  • Known hypersensitivity to phenylbutyric acid (PBA) or any excipients of the NaPBA/PBA formulations.
  • Pregnant or breast-feeding patients. Women of childbearing potential must have a pregnancy test performed at the Baseline Visit prior to the start of study drug.

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: None (Open label)

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16 participants in 2 patient groups

RAVICTI -> RAVICTI

Experimental group

Description:

Initial Treatment, Maintenance, Safety Extension Periods: RAVICTI, Oral Liquid Product 17.5 mL maximum total daily dose. Dosing will be based on participants disease and treatment status at entry to the study.

Treatment:

Drug: RAVICTI

NaPBA -> RAVICTI

Active Comparator group

Description:

Initial Treatment Period: NaPBA dosing based on participants disease and treatment status at entry to the study. Transition, Maintenance, Safety Extension Periods: RAVICTI, Oral Liquid Product 17.5 mL maximum total daily dose. Dosing will be based on participants disease and treatment status at entry to the study.

Treatment:

Drug: NaPBA