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Urea Cycle DisordersNCT06904027

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

An observational study of Urea Cycle Disorders, run by Tongji Hospital at 5 sites in China.

Recruiting

Looking for participants now. Contact the study team or a site below to ask about taking part.

Sites and contacts
Official record
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Trial 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… Read more about this study

Who is it for?
Ages 0 to 18 years
Conditions the study is for
Urea Cycle Disorders
What is being tested?
Glycerol phenylbutyrate Oral Liquid
Type of treatment
Pill or oral medicine
How many people
40 participants
Where
5 sitesChina
Study dates
9 Dec 2025to Jul 2031
Phase
Observational
Are there results?
Not yet: the study is under way

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 0 to 18 years
  • All sexes
  • No healthy volunteers
  • Child, Adult

Study population: Long term treatment for pediatric patients with UCD, aged 0-18 years, who cannot be managed with protein restriction and/or amino acid supplementation alone, including carbamoyl phosphate synthetase I deficiency, ornithine carbamoyltransferase deficiency, citrullinemia type I, argininosuccinic aciduria, argininemia, and hyperornithinemia-hyperammonemia-homocitrullinuria (HHH) syndrome.

Who may be able to join

  • Male or female aged 0-18 years;
  • Subject and/or subject's legally authorized representative willing to follow the therapeutic regimen, dietary management and visit plan of the study, and voluntarily signing informed consent form;
  • Patients with the following subtypes of UCD: Carbamoyl phosphate synthetase I deficiency, Ornithine translocase deficiency, citrullinemia type I, argininosuccinic aciduria, argininemia, and hyperornithinemia-hyperammonemia-homocitrullinuria (HHH) syndrome;
  • Patients planned to use glycerol phenylbutyrate who have not used it in past 3 months (including at the time of 3 months);
  • Men with fertility and women of childbearing potential (with menstruation) who are willing to take effective contraceptive measures during the period from the date of signing the informed consent to 1 months after the last dose of the study drug, such as abstinence, condoms, intra-uterine contraceptive devices, and double barrier methods (such as condoms + contraceptive diaphragms). Pregnancy test results must be negative for women of childbearing age within ≤ 7 days before the initial administration of study drug.

Who cannot join

  • Hypersensitivity to any of the active ingredient, including phenylbutyrate (PBA), phenylacetate acid (PAA) and phenylacetyl glutamine (PAGN), or excipients;
  • Use of any drug known to significantly affect renal clearance (such as probenecid) or increase protein catabolism (such as corticosteroids) or other drugs known to increase blood ammonia levels (such as valproate) within 24 h before the first administration;
  • Use of other nitrogen-scavenging agent at the same time after enrollment, such as sodium phenylbutyrate and sodium benzoate;
  • Pregnant or breastfeeding females.
  • Other reasons, in the opinion of the investigator, that may affect the patient's compliance and safety in participating in the study.

Trial locations and contacts

5 sites in 1 country. Contact the study team or a site near you to ask about taking part.

Xiaoping Luo, M.D. contact

027-83662640

xpluo@tjh.tjmu.edu.cn

5 sites in 1 country

China5 sites, 5 recruiting
  • Peking University First Hospital

    Beijing, Beijing Municipality, 100034

    Yang, M.D., 010-83572211, organic.acid@126.com

    Recruiting
  • Guangzhou Women and Children's Medical Center

    Guangzhou, Guangdong, 510000

    Liu, M.D., 020-81886332, liliuxia@hotmail.com

    Recruiting
  • Children's Hospital of Zhejiang University School of Medicine

    Hangzhou, Zhejiang

    Dong, M.D., 0571-87061007, 6305022@zju.edu.cn

    Recruiting
  • Xinhua Hospital, Shanghai Jiao Tong University School of Medicine

    Shanghai, Shanghai Municipality, 200092

    Qiu, M.D., 021-2507 8999, qiuwenjuanxh@163.com

    Recruiting
  • Tongji Hosipital

    Wuhan, Hubei, 430030

    Luo, M.D., 027-83662640, xpluo@tjh.tjmu.edu.cn

    Recruiting

Other trials in China

About this study

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

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.

Read the 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.

Being tested
Glycerol phenylbutyrate Oral Liquid
Keywords
Chinese, Pediatric patients, Urea cycle disorders, Glycerol phenylbutyrate
Medical subject headings
Urea Cycle Disorders, Inborn

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • Glycerol phenylbutyrate Oral LiquidDrug

    Also called HPN-100, GT4P, Glyceryl tri-(4-phenylbutyrate), RAVICTI

    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
    1. 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).
Study groups in NCT06904027
Study groupRoleWhat they receive
Glycerol phenylbutyrate cohortGlycerol Phenylbutyrate was used.
Receives: Drug: Glycerol phenylbutyrate Oral Liquid

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Mean blood ammonia levels at month 3 after enrollment.

    The average of blood ammonia levels at months 3 after enrollment.

    Measured: months 3

Secondary outcomes (12)
  1. Mean blood ammonia levels

    The average of blood ammonia levels at period of baseline, month 1, month 6, and every 6 months thereafter (1-5 years)

    Measured: Baseline, Month 1, Month 6, and every 6 months thereafter (1-5 years)

  2. Maximum blood ammonia levels

    The maximum blood ammonia levels at period of baseline, month 1, month 3, month 6, and every 6 months thereafter (1-5 years)

    Measured: Baseline, Month 1, Month 3, Month 6, and every 6 months thereafter (1-5 years)

  3. Frequency of hyperammonaemic crisis

    The frequency of hyperammonaemic crisis at period of baseline, month 1, month 3, month 6, and every 6 months thereafter (1-5 years)

    Measured: Baseline, Month 1, Month 3, Month 6, and every 6 months thereafter (1-5 years)

  4. Height

    The change of height to the baseline in children aged 0-18 years old, and the proportion of weight in the upper, upper-middle, middle, lower-middle, and lower categories for each age group, according to the growth standards for children under 7 years old (WS/T 423-2022) and standard for height level classification among children and adolescents aged 7~18 years (WS/T 612-2018)issued by the National Health Commission of the People's Republic of China.

    Measured: Baseline, Month 1, Month 3, Month 6, and every 6 months thereafter (1-5 years).

  5. Weight

    The change of weight to the baseline in children aged 0-7 years old, and the proportion of weight in the upper, upper-middle, middle, lower-middle, and lower categories for each age group, according to the growth standards for children under 7 years old issued by the National Health Commission of the People's Republic of China (WS/T 423-2022).

    Measured: Baseline, Month 1, Month 3, Month 6, and every 6 months thereafter (1-5 years)

  6. Head circumference

    The change of head circumference to the baseline in children aged 0-3 years old, and the proportion of head circumference in the upper, upper-middle, middle, lower-middle, and lower categories for each age group, according to the growth standards for children under 7 years old issued by the National Health Commission of the People's Republic of China (WS/T 423-2022).

    Measured: Baseline, Month 1, Month 3, Month 6, and every 6 months thereafter (1-5 years)

  7. Dose adjustment changes

    The changes of dose adjustment in glycerol phenylbutyrate throughout the study

    Measured: Baseline, Month 1, Month 3, Month 6, and every 6 months thereafter (1-5 years)

  8. Mean Neonatal Behavioral Neurological Assessment Scores: Behavioral ability, passive muscle tone, active muscle tone, primitive reflexes, and general assessment

    The neonatal behavioral neurological assessment (NBNA) scale was used for newborn participants who were at least 2 months of age, consisting of 20 items, with a maximum score of 40 points. The total scores of the NBNA are derived from the cumulative sum of the scores obtained in behavioral ability (6 items), passive muscle tone (4 items), active muscle tone (4 items), primitive reflexes (3 items), and general assessment (3 items), which are collected according to the scales have been actually completed by the subjects in the clinical practice. The total scores greater than 37 is considered normal, while a score less than or equal to 37 is considered abnormal.

    Measured: Month 6, every year thereafter (1-5 years)

  9. Mean Bayley Scale of Infant Development Scores: mental scale, motor scale

    The Bayley Scale of Infant Development was used for infant participants whose ages range from 2 months to 30 months, consisting of 244 behavioral items, including 163 items on the mental scale and 81 items on the motor scale. The scores of each infant on the mental and motor scales are converted into standard scores with a mean of 100 and a standard deviation of 16 according to age groups, thereby calculating the Mental Development Index (MDI) and the Psychomotor Development Index (PDI). A total score of MDI and PDI, which are collected according to the scales have been actually completed by the subjects in the clinical practice, are less than 70 indicates developmental delay, 70-79 indicates a borderline state, 80-89 indicates low average, 90-109 indicates average, 110-119 indicates high average, 120-129 indicates superior, and a score of 130 or above indicates very superior.

    Measured: Month 6, every year thereafter (1-5 years)

  10. Mean Gesell Developmental Diagnosis Scale Scores

    The assessment for Gesell Developmental Diagnosis Scale Scores was used for participants whose ages range from 30 months to 6 years, including five areas: gross motor skills, fine motor skills, adaptive behavior, language, and personal-social behavior. The observed behavioral patterns are identified based on the standard of normal behavioral patterns and are expressed in terms of age. This age is then compared with the actual age to calculate the Developmental Quotient (DQ), which is DQ = Developmental Age / Actual Age × 100, and the values of DQ are collected according to the scales have been actually completed by the subjects in the clinical practice. A DQ of 85 or above is considered normal for the nervous system, a DQ between 75 and 85 (inclusive of 75 but exclusive of 85) indicates a borderline level of nervous system impairment, and a DQ below 75 indicates nervous system damage.

    Measured: Month 6, every year thereafter (1-5 years)

  11. Mean Wechsler Preschool and Primary Scale of Intelligence Scores: The Verbal Intelligence Quotient, the Performance Intelligence Quotient

    The Chinese - Wechsler Preschool and Primary Scale of Intelligence (C - WYCSI) was used for children participants whose ages range from 4 to 6 years. The Verbal Intelligence Quotient (VIQ) test includes five subtests: Information, Picture Vocabulary, Arithmetic, Picture Comprehension, and Comprehension. The Performance Intelligence Quotient (PIQ) test includes five subtests: Animal Hatching, Picture Completion, Mazes, Geometric Shapes, and Block Design. The intelligence quotient (IQ) score obtained from the 10 subtests of VIQ and PIQ is the Full Intelligence Quotient (FIQ). The values for VIQ, PIQ and FIQ are collected according to the scales have been actually completed by the subjects in the clinical practice. FIQ is divided into five levels: ≥130 is superior, 116 - 129 is above average, 85 - 115 is average, 70 - 84 is below average, and < 70 is intellectual disability.

    Measured: Month 6, every year thereafter (1-5 years)

  12. Mean Wechsler Intelligence Scale for Children Scores: The Verbal Intelligence Quotient, the Performance Intelligence Quotient

    The Chinese-Wechsler intelligence scale of children (C-WISC)was used for participants whose ages range from 7 to 18 years. This scale consists of 11 subtests. The Verbal Intelligence Quotient (VIQ) test includes Information, Comprehension, Similarities, Arithmetic, Digit Span, and Vocabulary. The Performance Intelligence Quotient (PIQ) test includes Picture Completion, Picture Arrangement, Block Design, Object Assembly, and Coding. First, the raw score is calculated based on the test results of the examinee. Then, the corresponding age-specific scale score coefficient is checked and converted into a scale score. The sum of the VIQ and PIQ scale scores is the full intelligence quotient (FIQ) score, which are collected according to the scales have been actually completed by the subjects in the clinical practice. A FIQ of ≥120 is classified as high intelligence, 90-119 is classified as normal intelligence, and a score < 90 is classified as low intelligence.

    Measured: Month 6, every year thereafter (1-5 years)

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted1 Apr 2025
  2. Study start9 Dec 2025
  3. Primary completionSep 2026 (estimated)
  4. Study completionJul 2031 (estimated)

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Observational
Observational model
Cohort
Time perspective
Prospective
Enrolment
40 participants (estimated)
IDs, dates and publications
ClinicalTrials.gov ID
NCT06904027
Sponsor's protocol ID
WH002A401
Status last verified
Apr 2026
First submitted
10 Mar 2025
Last updated
27 Apr 2026
Results posted
No
Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No
Individual data sharing
No

Questions about this trial

What is this clinical trial studying?

An observational study of Urea Cycle Disorders, run by Tongji Hospital at 5 sites in China.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 5 inclusion and 5 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: looking for participants now, as of the sponsor's last update on 27 Apr 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 5 sites in China. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

Are results available for this study?

This study is still under way. Results are not available in the source record yet.

How can a doctor refer a patient or contact the research team?

Contact Xiaoping Luo, M.D. (027-83662640, xpluo@tjh.tjmu.edu.cn), or a site near the patient. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Mean blood ammonia levels at month 3 after enrollment. (time frame: months 3). It is what the study was designed to measure, not a finding.

Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 27 Apr 2026.

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