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Glycerol Phenylbutyrate

Clinical trials are investigating Glycerol Phenylbutyrate in people with pyruvate dehydrogenase deficiency and corticobasal syndrome. These studies aim to assess treatment effects, safety, and tolerability in small patient groups. The trials are in Phase 2 and use patient-reported and laboratory outcomes.

Table of Contents

Trial overview

Two authorised Phase 2 clinical trials are studying Glycerol Phenylbutyrate in different patient groups.[1][2] One trial is in people with pyruvate dehydrogenase deficiency, and the other is in people with corticobasal syndrome.[1][2] Both are interventional studies, which means the researchers give a treatment and then measure the results.[1][2]

Pyruvate dehydrogenase deficiency study

The first study is titled PDH-RAVICTI and is a multicentre, prospective, non-comparative Phase 2 trial in patients with pyruvate dehydrogenase deficiency (PDH).[1] It plans to enrol 15 participants and is authorised.[1] The study is looking at whether treatment with Glycerol Phenylbutyrate can improve fatigue over 6 months.[1]

The main outcome is measured with the Pediatric Quality of Life Inventory Multidimensional Fatigue Scale, a questionnaire that checks tiredness and its effect on daily life.[1] The trial will compare the score at the start of the study with the score at 6 months.[1] A 20% improvement in the total score is defined in the trial as a successful treatment effect.[1]

The treatment in this study is listed as RAVICTI 1.1 g/ml oral liquid, given by mouth, by nasogastric tube, or by percutaneous endoscopic gastrostomy tube use.[1] The trial description does not provide a comparison group, so it is a non-comparative study.[1]

Corticobasal syndrome study

The second study is a double-blind, randomised, prospective, placebo-controlled Phase 2 trial in patients with corticobasal syndrome (CBS).[2] It plans to enrol 32 participants and is also authorised.[2] This study is designed to test whether Glycerol Phenylbutyrate lowers neurofilament light chain (NfL) levels during 26 weeks of exposure.[2]

Neurofilament light chain is a blood marker used in the trial as a sign of nerve cell damage.[2] The study compares Glycerol Phenylbutyrate with placebo, which is an inactive treatment used for comparison.[2] The brief summary also says the trial will assess safety and tolerability in people with CBS.[2]

The safety plan includes checking adverse reactions, laboratory tests, vital signs such as blood pressure and heart rate, physical and neurological examination, and survival time and survival rate during the study period.[2] The tolerability outcome looks at how many participants stop the trial because of adverse reactions.[2]

Study designs and phases

Both trials are in Phase 2, which usually means researchers are looking for early signs that the treatment may help, while still watching safety closely.[1][2] The PDH study is non-comparative, while the CBS study is randomised, double-blind, and placebo controlled.[1][2]

  • Randomised means participants are assigned to a group by chance, which helps make the groups fair for comparison.[2]
  • Double-blind means neither the participants nor the study team know who is getting the real treatment or placebo during the trial.[2]
  • Placebo-controlled means the study includes an inactive treatment group so the results can be compared more clearly.[2]
  • Prospective means the researchers follow participants forward in time after the trial starts.[1][2]
  • Multicentric means the study is carried out at more than one center or hospital.[1]

Main outcomes and what they mean

In the PDH study, the main outcome is fatigue, which means tiredness that can affect daily life and energy levels.[1] The researchers will look for a change in fatigue score from the start of the study to 6 months.[1]

In the CBS study, the main outcome is the change in plasma NfL, which is a blood measure linked to nerve injury.[2] The study also includes safety outcomes, such as adverse reactions, lab tests, vital signs, and examination findings, to see how the treatment is tolerated.[2]

These outcomes show that the trials are not only asking whether Glycerol Phenylbutyrate may help, but also whether it can be studied safely in these patient groups.[1][2]

Who may take part

The source data identifies two target populations: patients with pyruvate dehydrogenase deficiency and patients with corticobasal syndrome.[1][2] The PDH study uses a small group of 15 participants, and the CBS study plans to include 32 participants.[1][2]

Because the source data does not list full eligibility rules, age limits, or exclusion criteria, those details cannot be confirmed here.[1][2] What is clear is that each trial is focused on a specific condition and a defined patient group.[1][2]

Trial ID Phase Condition studied Status Enrollment
2024-516410-38-00 Phase 2 Pyruvate dehydrogenase deficiency Authorised 15
2024-516897-31-00 Phase 2 Corticobasal Syndrome (CBS) Authorised 32

FAQ

  • What conditions are being studied in Glycerol Phenylbutyrate trials? The trials in the source data study pyruvate dehydrogenase deficiency and corticobasal syndrome. These are different conditions, so the studies are looking at different patient groups and different outcomes.
  • Who can take part in these trials? People with pyruvate dehydrogenase deficiency may be included in one study, and people with corticobasal syndrome may be included in another. Each trial has its own rules for who can join.
  • What phase are the studies? Both trials are Phase 2 studies. Phase 2 means the treatment is being tested in a small group to learn more about early effectiveness and safety.
  • What are the trials trying to measure? One trial measures fatigue after 6 months using a quality-of-life fatigue scale. The other trial measures change in neurofilament light chain, a blood marker linked to nerve cell damage, and also checks safety and tolerability.
  • Are these trials comparing Glycerol Phenylbutyrate with another treatment? One study is non-comparative, so it does not compare against another treatment. The other study is placebo controlled, which means it compares Glycerol Phenylbutyrate with a placebo, an inactive treatment.

Ongoing Clinical Trials on Glycerol Phenylbutyrate

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

    Recruiting

    2 1 1 1
    Investigated drugs:
    France

  • Study on the Effects of Glycerol Phenylbutyrate in Patients with Corticobasal Syndrome

    Not recruiting

    2 1 1
    Investigated diseases:
    Investigated drugs:
    Germany

Glossary

  • Phase 2: A study stage that tests early signs of benefit and continues to check safety in a small group of patients.
  • Interventional study: A clinical trial where researchers give a treatment and then measure what happens.
  • Non-comparative: A study design without a control group to compare against.
  • Placebo: An inactive treatment that looks like the real treatment and is used for comparison.
  • Randomised: Patients are assigned to study groups by chance.
  • Double-blind: A study design where patients and researchers do not know who gets the real treatment or placebo.
  • Primary outcome: The main result a trial is designed to measure.
  • PedsQL Multidimensional Fatigue Scale: A questionnaire used to measure fatigue, or tiredness, in children and adolescents.
  • Neurofilament light chain (NfL): A blood marker that can reflect nerve cell injury or damage.
  • Tolerability: How well patients can continue a treatment without having to stop because of side effects or reactions.
  • Adverse reactions: Unwanted medical problems that happen during a study and may be related to the treatment.

References

  1. https://clinicaltrials.gov/study/2024-516410-38-00
  2. https://clinicaltrials.gov/study/2024-516897-31-00