Skip to content
Clinical Trials – home

Rare diseases

Investigational molecules

Locations

Our offerNewsroom

Not recruitingRare disease

Study on the Effects of AMX0035 (Phenylbutyrate and Ursodoxicoltaurine) in Patients with Progressive Supranuclear Palsy

Verified siteInvestigational
Clinical Trials Concierge

Prefer not to search? Our Concierge searches the trials for you.

What is this trial about?

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

This clinical trial is focused on studying a disease called Progressive Supranuclear Palsy (PSP). PSP is a rare brain disorder that affects movement, balance, and eye movements. The study will test a treatment known as AMX0035, which is a combination of two substances: phenylbutyrate and ursodoxicoltaurine. These substances are being investigated to see if they can help slow down the progression of PSP.

The purpose of the study is to assess the impact of AMX0035 compared to a placebo on the rate of disease progression. Participants in the study will receive either AMX0035 or a placebo, which is a substance with no active medication. The study will last for a period of time, during which participants will take the treatment orally in the form of a powder. The study will monitor changes in the participants' condition using a scale called the Progressive Supranuclear Palsy Rating Scale (PSPRS), which measures the severity of symptoms.

Throughout the study, participants will have regular visits to check their health and monitor any changes in their symptoms. The study will also track any side effects or adverse events that may occur. The goal is to determine if AMX0035 can effectively slow down the progression of PSP and improve the quality of life for those affected by this condition.

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

    Upon joining the study, an initial assessment is conducted to confirm eligibility. This includes a review of medical history and a physical examination.

    A series of tests, including a Mini Mental State Examination (MMSE), are performed to evaluate cognitive function.

  2. Step 2

    Baseline measurements

    Baseline measurements are taken to establish a starting point for the study. This includes the Progressive Supranuclear Palsy Rating Scale (PSPRS) to assess the severity of symptoms.

    Additional tests may include MRI scans and laboratory tests to gather comprehensive health data.

  3. Step 3

    Medication administration

    Participants receive either the study drug AMX0035 or a placebo. AMX0035 contains phenylbutyrate and ursodoxicoltaurine, administered in powder form.

    The medication is taken orally, with the dosage and frequency determined by the study protocol.

  4. Step 4

    Regular follow-up visits

    Regular follow-up visits are scheduled to monitor progress and assess any changes in symptoms. These visits include repeated PSPRS assessments and other relevant tests.

    Participants are required to report any side effects or changes in health status during these visits.

  5. Step 5

    Final assessment

    At the end of the study period, a final assessment is conducted to evaluate the overall impact of the treatment.

    The primary endpoint is the change from baseline in the PSPRS score at Week 52.

Who can join the trial?

17 criteria

  • Must provide a signed informed consent form, showing they understand the study. If unable to sign, a representative can sign for them.
  • Must score 24 or higher on the Mini Mental State Examination, a test that checks mental abilities.
  • Any medications for Parkinson's disease should be stable for 60 days before joining the study and expected to stay the same during the study.
  • All female participants must have a negative pregnancy test at the start of the study.
  • Women who can have children and are sexually active must have a negative pregnancy test on the first day before taking the study drug.
  • Women who can have children must agree to avoid pregnancy by not having sex or using effective birth control during the study and for 6 months after the last dose.
  • Women must not plan to become pregnant or breastfeed during the study and for 6 months after the last dose.
  • Men must agree to avoid fathering a child by not having sex or using effective birth control during the study and for 6 months after the last dose.
  • Men must not plan to father a child or donate sperm during the study and for 6 months after the last dose.
  • Must be willing and able to attend scheduled visits, follow the treatment plan, and complete tests, including MRI scans.
  • Must have a study partner, like a caregiver or family member, who can attend visits and provide information about the participant's abilities.
  • Must be between 40 and 80 years old.
  • Must not live in a skilled nursing or dementia care facility at the start of the study, but living in an assisted living facility is allowed.
  • Must meet certain criteria for Progressive Supranuclear Palsy (PSP), including symptoms like difficulty moving the eyes up and down or balance problems.
  • Must have had PSP symptoms for less than 5 years, as judged by the study doctor.
  • Must score less than 40 on the PSP Rating Scale, which measures the severity of PSP symptoms.
  • Must be able to walk independently or with minimal help, meaning they can walk 5 steps with just one arm for support.

Who cannot join the trial?

10 criteria

  • Having any other serious medical condition that could interfere with the study.
  • Being unable to follow the study procedures or instructions.
  • Having a history of severe allergic reactions to any of the study medications.
  • Being pregnant or breastfeeding.
  • Participating in another clinical trial at the same time.
  • Having a significant mental health condition that could affect participation.
  • Having a history of drug or alcohol abuse.
  • Having a condition that affects the brain, other than the one being studied.
  • Having a recent major surgery or planning to have one during the study.
  • Having a condition that affects the immune system, which helps fight infections.
Clinical Trials Concierge

Prefer not to search? Our Concierge searches the trials for you.

Tell us about your condition – we search every trial in Europe and connect you with the right site.

We usually reply within a few days

Verified sites

All sites with verified contact details – recruitment status may not be available; ask directly

Trial locations

Where you can join this trial

Countries are shaded by recruitment status. Click a recruiting country to ask about joining there.

Not recruiting
Not finding your country?

Not sure what to do next?

Joining a clinical trial can seem overwhelming. We guide you step by step, so you know exactly what to expect and how we support you through the process.

See the full process and FAQ

Investigated drugs

AMX0035 is a medication being studied for its potential to slow down the progression of Progressive Supranuclear Palsy (PSP). This condition affects movement, balance, and eye movements. The trial aims to see if AMX0035 can help improve or stabilize symptoms in patients with PSP.

What is already known about the treatment

AMX0035 – This medication is administered orally in the form of tablets. It is currently being studied in clinical trials for its potential use in treating Progressive Supranuclear Palsy, a rare brain disorder. The main therapeutic indication for AMX0035 is to slow the progression of this disease. At the molecular level, AMX0035 works by protecting nerve cells from damage, which may help in preserving brain function. It is classified pharmacologically as a neuroprotective agent.

Investigated diseases

Progressive Supranuclear Palsy – Progressive Supranuclear Palsy is a rare brain disorder that affects movement, control of walking, balance, speech, swallowing, vision, mood, and behavior. It is characterized by the gradual deterioration of specific areas in the brain, leading to symptoms such as stiffness, awkward movements, and difficulties with eye movements. As the disease progresses, individuals may experience increased difficulty with balance and coordination, often resulting in falls. Speech and swallowing problems can also develop, making communication and eating challenging. The condition is progressive, meaning symptoms worsen over time, and it primarily affects middle-aged and older adults.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2023-505893-14-00Protocol codeA35-009Estimated enrolment910 patientsSponsorAmylyx Pharmaceuticals Inc.

sourced from the EU Clinical Trials Register and site verification

Want to learn more about this trial or check if you can participate?

Clinical Trials Concierge

Prefer not to search? Our Concierge searches the trials for you.

Tell us about your condition – we search every trial in Europe and connect you with the right site.