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Study of glycerol phenylbutyrate (oral liquid) for treatment of fatigue in patients with pyruvate dehydrogenase deficiency

Verified siteRegistered drugNo placebo
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What is this trial about?

A plain-language summary of the goals, design and what participants do

This clinical trial focuses on studying Pyruvate Dehydrogenase Deficiency, a rare genetic condition that affects how the body processes certain nutrients. The study will test a medication called Glycerol Phenylbutyrate (also known as RAVICTI), which is given as a liquid that can be taken by mouth or through feeding tubes.

The purpose of this research is to evaluate how well Glycerol Phenylbutyrate works in reducing tiredness and fatigue in people who have Pyruvate Dehydrogenase Deficiency. The study will last for 6 months, during which participants will take the medication daily. The maximum daily dose of the medication will be 12 grams.

The treatment will be given as a liquid medicine that can be taken orally or administered through a nasogastric tube or gastrostomy tube (a feeding tube that goes directly into the stomach). Throughout the study, doctors will monitor how the treatment affects participants' energy levels and overall well-being using specialized questionnaires that measure fatigue levels.

The research process

The trial runs in 5 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Initial assessment

    Your doctor will perform baseline evaluations and complete the PedsQL™ Multidimensional Fatigue Scale questionnaire to assess your current fatigue level

    This initial assessment will establish your starting point (M0) for measuring treatment effectiveness

  2. Step 2

    Starting medication

    You will begin taking RAVICTI (glycerol phenylbutyrate) oral liquid

    The medication is administered through mouth, nasogastric tube, or stomach feeding tube

    Your doctor will provide specific dosing instructions for the liquid medication

  3. Step 3

    Treatment period

    Continue taking RAVICTI as prescribed for 6 months

    Regular follow-up visits will be scheduled to monitor your progress

    Your doctor will track any changes in your condition during this period

  4. Step 4

    6-month evaluation

    After 6 months of treatment (M6), you will complete the fatigue scale questionnaire again

    Your doctor will compare the results with your initial assessment

    A 20% improvement in the overall score indicates treatment success

  5. Step 5

    Study completion

    Final medical evaluation will be performed

    Your doctor will discuss the results with you

    Continue using effective contraception for 7 days after study completion if applicable

Who can join the trial?

9 criteria

  • Age requirement: Must be either a child between 2 and 17 years old OR an adult between 18 and 25 years old
  • Must have confirmed PDH deficiency (a rare genetic condition affecting energy production in cells) proven through genetic testing with specific variants in one of these genes:
    • PDHA1 gene with specific type of genetic change
    • PDHB or DLAT genes with specific genetic changes
    • PDHX gene with specific genetic changes
    • For women who can become pregnant:
      • Must have a negative pregnancy test
      • Must use effective birth control methods (such as birth control pills, IUD, barrier methods with spermicide, or abstinence) until 7 days after study end
      • For men:
        • Must use effective birth control (condom or abstinence) until 7 days after study end
        • Must have legal representative's signature for participation
        • Must have active social security coverage

Who cannot join the trial?

12 criteria

  • Current treatment with sodium phenylbutyrate (a medication used to treat urea cycle disorders)
  • Known allergic reactions to glycerol phenylbutyrate or similar substances
  • Severe liver problems or abnormal liver function tests
  • Pregnant women or women planning to become pregnant during the study
  • Breastfeeding mothers
  • Participation in another clinical trial within the last 30 days
  • Any serious medical condition that could interfere with study participation
  • Unable to follow study procedures or attend scheduled visits
  • History of non-compliance with medical treatments
  • Mental conditions that could affect the ability to provide informed consent
  • Active substance abuse or addiction
  • Use of medications that could interact with the study drug
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Investigated drugs

Glycerol Phenylbutyrate (RAVICTI) is a medication used to treat patients with Pyruvate Dehydrogenase Deficiency (PDH). It works by helping the body manage certain metabolic processes. The medication is designed to reduce fatigue in patients with this rare metabolic condition. RAVICTI is taken orally and helps control the buildup of harmful substances in the body that can occur in people with PDH.

What is already known about the treatment

Glycerol Phenylbutyrate (RAVICTI) - An oral medication administered in liquid form that functions as a nitrogen-binding agent used in the treatment of Pyruvate Dehydrogenase Deficiency (PDH), a rare metabolic disorder. The medication works by converting excess nitrogen into a form that can be safely removed from the body through urination, helping to prevent toxic buildup of ammonia in the blood. As a pharmaceutical agent classified under nitrogen-scavenging drugs, RAVICTI has shown promise in clinical trials for managing PDH symptoms, particularly in reducing fatigue and improving quality of life for patients with this metabolic condition.

Investigated diseases

Pyruvate dehydrogenase deficiency - A rare genetic metabolic disorder that affects how the body processes certain nutrients to produce energy. The condition occurs when an enzyme called pyruvate dehydrogenase complex (PDC) fails to break down pyruvate properly in cells. This leads to a buildup of lactic acid in the body and prevents cells from producing enough energy. People with this condition often experience fatigue, muscle weakness, and poor muscle tone. The symptoms typically begin in infancy or early childhood and can vary in severity among different individuals.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IITrial ID2024-516410-38-00Protocol codeAPHP230834Estimated enrolment15 patientsSponsorAssistance Publique Hopitaux De Paris

sourced from the EU Clinical Trials Register and site verification

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