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Study of utreloxastat (PTC857) in adults with Amyotrophic Lateral Sclerosis (ALS) to evaluate its effectiveness in slowing disease progression

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What is this trial about?

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

This study focuses on Amyotrophic Lateral Sclerosis (ALS), a condition that affects nerve cells controlling muscle movement, leading to progressive muscle weakness. The research evaluates a new medication called PTC857 (also known as utreloxastat) which is given as an oral solution. The purpose of the study is to determine if PTC857 can slow down the progression of ALS.

The study compares PTC857 with placebo in people who have ALS. Participants will receive either PTC857 or placebo for 24 weeks. During this time, patients can continue taking their standard ALS medications, including riluzole, edaravone, or sodium phenylbutyrate/taurursodiol, as long as they were already using these medications before joining the study.

The research will measure how the disease progresses by looking at changes in physical function and survival. The study will also check how safe PTC857 is and how well patients tolerate it. Additionally, researchers will examine the medication's effects by measuring certain substances in the blood and spinal fluid that may indicate how the disease is developing.

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

    You will undergo an evaluation to confirm your diagnosis of amyotrophic lateral sclerosis (ALS) and verify that your symptoms started within the last 24 months

    Your breathing capacity will be tested to ensure it is at least 60% of normal function

    Your ALS Functional Rating Scale-Revised (ALSFRS-R) score must be at least 34 points to participate

  2. Step 2

    Treatment assignment

    You will be randomly assigned to receive either PTC857 oral solution or a matching placebo

    Neither you nor your doctor will know which treatment you are receiving

    If you are currently taking other ALS medications (riluzole, edaravone, or sodium phenylbutyrate/taurursodiol), you can continue using them if the dose remains stable

  3. Step 3

    Treatment period

    The treatment period will last 24 weeks

    You will take the assigned medication orally according to the prescribed schedule

    Regular assessments will track changes in your ALS symptoms and overall function

  4. Step 4

    Monitoring and assessments

    Your ALS symptoms will be evaluated using the ALSFRS-R scale

    Regular breathing tests will measure your lung function

    Blood samples will be collected to measure medication levels and disease markers

    Quality of life assessments will be conducted using a specialized questionnaire

    Safety monitoring will include physical examinations, vital signs, and laboratory tests

  5. Step 5

    Final evaluation

    After 24 weeks, a final assessment will measure the changes in your condition

    The effectiveness of the treatment will be evaluated based on your functional abilities and survival

    Follow-up safety assessments will be conducted

Who can join the trial?

13 criteria

  • Age between 18 and 80 years at screening
  • Diagnosed with ALS within the last 24 months before screening
  • Have an ALSFRS-R score (a scale that measures physical function in ALS) of at least 34
  • Have adequate breathing function with slow vital capacity (a breathing test) of 60% or higher
  • Must be on stable doses of any regular medications for at least 14 days before screening
  • If taking ALS treatments (riluzole, edaravone, or sodium phenylbutyrate/taurursodiol), doses must be stable for at least 30 days before screening
  • Female participants must:
    • Have normal breast cancer screening within 6 months before screening
    • Not donate eggs during the study and for 90 days after
    • Be post-menopausal, surgically sterile, or use effective contraception
    • Male participants must:
      • Use barrier contraception if sexually active with females who could become pregnant
      • Not donate sperm during the study and for 90 days after
      • Must be able to understand and comply with study procedures
      • Must provide written informed consent to participate in the study

Who cannot join the trial?

14 criteria

  • Age below 18 or above 80 years old
  • Presence of any significant medical conditions that could interfere with the study, such as:
    • Severe heart disease
    • Uncontrolled high blood pressure
    • Active cancer
    • Severe kidney or liver problems
    • Participation in another clinical trial within the past 30 days
    • Known allergies to PTC857 or similar medications
    • Pregnancy or breastfeeding
    • Unable to provide informed consent
    • History of non-compliance with medical treatments
    • Use of medications that could interact with the study drug
    • Inability to attend regular study visits
    • Significant abnormal laboratory test results
    • Mental health conditions that could affect study participation
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Investigated drugs

PTC857 is an investigational medication being studied for treating amyotrophic lateral sclerosis (ALS). It is being tested to see if it can help slow down the progression of ALS symptoms in adult patients. This is a new drug that is still being researched and is currently known by its development code name since it hasn't yet been given a standard generic name.

What is already known about the treatment

PTC857 - An investigational drug being studied in clinical trials for the treatment of Amyotrophic Lateral Sclerosis (ALS), a progressive neurological disease. This experimental compound is currently in Phase 2 clinical trials to evaluate its effectiveness in slowing down disease progression in ALS patients. While the specific mechanism of action and form of administration are not publicly disclosed in the available trial data, the drug is being tested in a randomized, double-blind, placebo-controlled study to assess its efficacy, safety, tolerability, and pharmacokinetic properties. The clinical trial, known as CARDINALS, represents an important step in developing potential new treatments for ALS patients.

Investigated diseases

Amyotrophic Lateral Sclerosis – A progressive neurological disease that affects nerve cells responsible for controlling voluntary muscle movement. The condition causes the death of motor neurons, which gradually reduces a person's ability to move muscles. ALS affects various physical functions, including walking, speaking, swallowing, and breathing. The disease typically begins with muscle twitching, weakness in a limb, or slurred speech. As motor neurons degenerate, the brain loses its ability to control muscle movement.
Trial detailsLast updated 4 Oct 2026
Age18+ yearsPhasePhase IITrial ID2023-510317-26-00Protocol codePTC857-CNS-001-ALSEstimated enrolment336 patientsSponsorPTC Therapeutics Inc.

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