NCT06904027

A Clinical Study of Glycerol Phenylbutyrate in Chinese Patients With Urea Cycle Disorders

A Single-arm, Prospective, Multi-center Post-market Clinical Study of Glycerol Phenylbutyrate in Chinese Patients With Urea Cycle Disorders

• Status: Recruiting
• Phase: —
• Study type: Observational
• Enrollment: 40 (estimated)
• Sponsor: Tongji Hospital · Academic / Other
• Sex: All
• Age: 0 Years – 18 Years
• Healthy volunteers: Not accepted

Summary

Urea cycle disorders (UCD) are rare diseases in China, would lead to high mortality and disability, which require long-term management due to the recurrent symptoms. This multi-center, prospective, single-arm study was designed to assess the efficacy and safety of Glycerol Phenylbutyrate for Chinese pediatric patients with UCD, to provide the additional references and treatment options for Chinese UCD patients, and enhance the clinical management of UCD in China. This study primarily observes patients with UCD who are on long-term treatment with glyceryl phenylbutyrate, the total planned observation period is 5 years.

Detailed description

The duration of treatment with GPB in this study was 5 years. Forty participants aged 0-18 years with a diagnosis of UCD, including carbamoyl phosphate synthetase I deficiency, ornithine carbamoyltransferase deficiency, citrullinemia type I, argininosuccinic aciduria, argininemia, or hyperornithinemia-hyperammonemia-homocitrullinuria (HHH) syndrome, and who plan to use and have not used glycerol phenylbutyrate in the previous 3 months (including 3 months) were enrolled. Participants should return to clinic visits at 1 month and 3 months after enrollment. They were queried about any adverse events (AEs), dosage change of the study drug or hyperammonemic crises (HACs) that occurred since the last visit, and blood samples were collected for the analysis of ammonia and blood biochemistry. Then the detailed information on AEs, dosage change of the study drug, HACs, and data about ammonia, routine clinical laboratory safety tests and neurocognitive outcomes that have been actually completed in the clinical practice of the patients will be collected every 6 months until 5 years. Height, weight and/or head circumference data were also collected at each visit. The assessments would be conducted at 1, 3, and 6 months, and subsequently on a semi-annual basis. The evaluation of ammonia levels, frequency of HACs, dosage of the study drug, AEs, serious AEs, and concomitant medications were included. The neurocognitive outcomes, growth and development of the participants would be described at the end.

Conditions

• Urea Cycle Disorders

Interventions

Type	Name	Description
DRUG	Glycerol phenylbutyrate Oral Liquid	Administration and dosage: The recommended total daily dose of glycerol phenylbutyrate is calculated based on the patient's body surface area, ranging from 4.5 mL/m2/d to 11.2 mL/m2/d: 1. Recommended initial dose in phenylbutyrate-naïve patients * Patients with body surface area (BSA) \< 1.3 m2: 8.5 mL/m2/day * Patients with body surface area (BSA) ≥ 1.3 m2: 7 mL/m2/day 2. Initial dose for patients switching from sodium phenylbutyrate to glycerol phenylbutyrate: Total daily dose of glycerol phenylbutyrate (ml) = total daily dose of sodium phenylbutyrate granules (g) ×0.81 Medication Schedule: The daily total dose should be divided into equal amounts and administered with each meal or feeding (such as three to six times daily).

Timeline

• Start date: 2025-12-09
• Primary completion: 2026-10-01
• Completion: 2031-07-01
• First posted: 2025-04-01
• Last updated: 2026-01-15

Locations

5 sites across 1 country: China