PROFIL Study to Investigate the Effect of GPB on NfL Levels in Patients With Corticobasal Syndrome (CBS) (PROFIL)

September 8, 2026 updated by: Technical University of Munich

Double-blind, Randomised, Prospective, Placebo Controlled Parallel Group Phase II Study to Investigate the Effect of Glycerol Phenylbutyrate (GPB) on Neurofilament Light Chain (NfL) Levels in Patients With Corticobasal Syndrome (CBS)

Corticobasal syndrome (CBS) is a rapidly progressive neurodegenerative disorder with an average survival time of about 6-8 years after the first clinical manifestation. No potent symptomatic treatment is currently available. A disease-modifying therapy does not exist either. Neuroinflammation is key to the pathogenesis in neurodegenerative diseases with Tau- and/or AD-pathology. There is strong evidence that phenylbutyrate can modulate microglial function by enhancing their phagocytic activity, most likely by epigenetic mechanisms. So the main goal of this clinical trial is to study a potential disease-modifying effect of treatment with glycerol phenylbutyrate (GPB), which is a prodrug of phenylbutyric acid, for 26 weeks assessed by the levels of the biomarker neurofilament light chain (NfL) indicating disease progression in CBS. Given the aggressive nature of CBS, it is feasible to study effects of GPB on plasma NfL levels.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
32

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 2

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • Germany
    • Bavaria
      • Munich, Bavaria, Germany, 81377
        • Klinikum der Universität München (KUM), Campus Großhadern, Klinik und Poliklinik für Neurologie & German Center for Neurodegenerative Diseases (DZNE), Department of Neurology
      • Munich, Bavaria, Germany, 81377
        • Klinikum rechts der Isar Technische Universität München Klinik und Poliklinik für Neurologie & German Center for Neurodegenerative Diseases (DZNE), Department of Neurology

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  1. Age: ≥ 18 years
  2. "clinical possible" or "clinical probable" CBS (Armstrong et al., Neurol-ogy, 2013 80;496-503) and patients with Progressive Supranuclear Palsy-CBS according to Höglinger et al. (Mov Disord. 2017 Jun;32(6):853-864)
  3. No regular consumption of glycerol phenylbutyrate within the last 6 months prior to V1
  4. Capable of thoroughly understanding all information given and giving full informed consent according to GCP
  5. Capability and willingness to comply with the procedures of the clinical trial
  6. Women of childbearing age must be non-lactating and surgically sterile or using a highly effective method of birth control and have a nega-tive pregnancy test. In case of using a hormonal contraception, the method must be supplemented with a barrier method (preferably male condom). Acceptable methods of birth control with a low failure rate i.e. less than 1% per year when used consistently and correct are such as implants, injectables, combined oral contraceptives, hormonal intrauterine devices (IUDs), sexual abstinence (defined as refraining from heterosexual intercourse during the clinical trial) or vasectomized partner. Unacceptable birth control methods are: periodic abstinence (calendar, symptothermal, post-ovulation methods), withdrawal (coitus interruptus), spermicides only and lactational amenorrhoea method (LAM). Female condom and male condom should not be used together.

  7. A stable regimen for at least 1 month prior to V1 and no foreseeable need to change the regimen throughout the 26 week treatment period for

    1. drugs acting against Parkinsonism (e.g. Levodopa, Dopamine-Agonists, Amantadine and MAO-B-Inhibitors)
    2. other CNS-active substances including e.g. antidepressants and antidementia drugs

Exclusion Criteria:

  1. Neurodegenerative diseases other than CBS
  2. Underlying Alzheimer's pathology as defined by positive β-amyloid-PET or reduced Aβ 1-42 in CSF
  3. Participation in another clinical trial involving administration of an investigational medicinal product within 1 month or 5 half-lives of the investigational medicinal product, whichever is longer, prior to V1
  4. Known hypersensitivity to glycerol phenylbutyrate or its further components, or to drugs with a similar chemical structure or to any of the components of the placebo
  5. Treatment with valproic acid, haloperidol or probenecid
  6. A physical or psychiatric condition (e.g. frontal lobe syndrome, psychotic disorder or major depression), which at the investigator's discretion may put the subject at risk, may confound the trial results or may interfere with the subject's participation in this clinical trial
  7. Persistent abuse of medication, drugs or alcohol
  8. Current or planned pregnancy or breast-feeding in females
  9. Other severe medical conditions upon the discretion of the investigator

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Verum
RAVICTI 1.1 g/ml oral liquid (glycerol phenylbutyrate (GPB)) Duration of Treatment: 26 weeks, twice daily
Drug: RAVICTI 1.1 g/ml

Duration of Treatment: 26 weeks, twice daily

Dosage:

  • weeks 0 - 3: 3 ml/day (1,5ml - 0 - 1,5ml) (≙ 3,3 g glycerol phenylbutyrate/placebo)
  • weeks 4 - 26: 6 ml/day (3 ml - 0 - 3 ml) (≙ 6,6 g glycerol phenylbutyrate/placebo)
Other Names:
  • Glycerol phenylbutyrate
Placebo Comparator: Placebo
Matching Placebo, oral liquid Duration of Treatment: 26 weeks, twice daily
Drug: Placebo

Duration of Treatment: 26 weeks, twice daily

Dosage:

  • weeks 0 - 3: 3 ml/day (1,5ml - 0 - 1,5ml) (≙ 3,3 g glycerol phenylbutyrate/placebo)
  • weeks 4 - 26: 6 ml/day (3 ml - 0 - 3 ml) (≙ 6,6 g glycerol phenylbutyrate/placebo)

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
To assess the efficacy of glycerol phenylbutyrate vs. placebo in reducing the levels of neurofilament light chain (NfL) during 26 weeks of exposure to glycerol phenylbutyrate as well as safety and tolerability of glycerol phenylbutyrate in patients with
Time Frame: 26 weeks (between V1 and V3)
To assess the efficacy of glycerol phenylbutyrate vs. placebo in reducing the levels of neurofilament light chain (NfL) during 26 weeks of exposure to glyc-erol phenylbutyrate as well as safety and tolerability of glycerol phenylbutyrate in patients with CBS.
26 weeks (between V1 and V3)

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
To assess longitudinal changes in clinical scales
Time Frame: 26 weeks (between V1 and V3)
To assess longitudinal changes in clinical scale: Movement Disorder Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS Part III), min value 0- max value 132 (worse outcome)
26 weeks (between V1 and V3)
To assess longitudinal changes in clinical scales
Time Frame: 26 weeks (between V1 and V3)
To assess longitudinal changes in clinical scale: Progressive Supranuclear Palsy Rating Scale (PSP-RS), min value 0- max value 100 (worse outcome)
26 weeks (between V1 and V3)
To assess longitudinal changes in clinical scales
Time Frame: 26 weeks (between V1 and V3)
To assess longitudinal changes in clinical scale:Progressive Supranuclear Palsy Clinical Deficits Scale (PSP-CDS), min value 0- max value 21 (worse outcome)
26 weeks (between V1 and V3)
To assess longitudinal changes in clinical scales
Time Frame: 26 weeks (between V1 and V3)
To assess longitudinal changes in clinical scale: Cortical Basal ganglia Functional Scale (CBFS), min value 0- max value 124 (worse outcome)
26 weeks (between V1 and V3)
To assess longitudinal changes in clinical scales
Time Frame: 26 weeks (between V1 and V3)
To assess longitudinal changes in clinical scale: Dementia Apraxia Test (DATE), min value 0 (worse outcome) - max value 60
26 weeks (between V1 and V3)
To assess longitudinal changes in clinical scales
Time Frame: 26 weeks (between V1 and V3)
To assess longitudinal changes in clinical scale: MONTREAL COGNITIVE ASSESSMENT (MoCA), min value 0 (worse outcome) - max value 30
26 weeks (between V1 and V3)
To assess longitudinal changes in clinical scales
Time Frame: 26 weeks (between V1 and V3)
To assess longitudinal changes in clinical scale: SCHWAB AND ENGLAND ACTIVITIES OF DAILY LIVING SCALE (SEADL), min value 0 (worse outcome) - max value 100%
26 weeks (between V1 and V3)
To assess longitudinal changes in clinical scales
Time Frame: 26 weeks (between V1 and V3)
To assess longitudinal changes in clinical scale: Clinical Global Impression (CGI-s), min value 1- max value 7 (worse outcome)
26 weeks (between V1 and V3)
To assess longitudinal changes in clinical scales
Time Frame: 26 weeks (between V1 and V3)
To assess longitudinal changes in clinical scale: PSP RATING SCALE (PSP-QoL), min value 0- max value 180 (worse outcome)
26 weeks (between V1 and V3)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Technical University of Munich

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
December 12, 2023

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
August 13, 2026

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
August 13, 2026

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
July 13, 2023

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
August 1, 2023

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
August 9, 2023

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
September 11, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
September 8, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
August 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • PROFIL-2088-SIM-0032-I

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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