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Study on the Safety and Effects of PTC518 for Patients with Huntington's Disease

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What is this trial about?

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

This clinical trial is focused on studying Huntington's Disease, a genetic disorder that causes the progressive breakdown of nerve cells in the brain. The study is testing a new treatment called PTC518, which is taken as a tablet. The purpose of the study is to evaluate the safety of PTC518 and its effects on reducing a specific protein in the blood associated with Huntington's Disease. Participants in the study will receive either the PTC518 tablet or a placebo, which looks like the PTC518 tablet but does not contain the active medication.

The study will be conducted over a period of 12 months. During this time, participants will take the medication orally and will have regular check-ups to monitor their health and the effects of the treatment. These check-ups will include various assessments, such as blood tests and other evaluations, to track changes in the levels of the protein related to Huntington's Disease. The study aims to gather information on how well PTC518 works and its safety profile.

By participating in this study, researchers hope to gain valuable insights into the potential benefits of PTC518 for individuals with Huntington's Disease. The ultimate goal is to find a treatment that can help manage the symptoms and progression of this condition. The study is designed to ensure the safety and well-being of all participants throughout the research process.

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

    Joining the study

    Upon joining the study, participation is confirmed through informed consent. This involves understanding the study's purpose and agreeing to follow the study's requirements.

    Eligibility is based on specific criteria, including age, genetic confirmation of Huntington's disease, and certain health scores.

  2. Step 2

    Randomization and initial assessment

    Participants are randomly assigned to receive either the study medication, PTC518, or a placebo. This ensures that the study results are unbiased.

    Initial assessments are conducted to establish baseline health data. This includes blood tests and other evaluations to measure health status before starting the medication.

  3. Step 3

    Medication administration

    Participants take the assigned medication orally in tablet form. The dosage and frequency are determined by the study protocol.

    The study medication, PTC518, is administered in varying doses to evaluate its safety and effectiveness.

  4. Step 4

    Ongoing monitoring and assessments

    Regular monitoring is conducted to track health changes and any side effects. This includes laboratory tests, vital signs checks, and other health assessments.

    Participants undergo periodic evaluations to measure changes in specific health markers, such as blood protein levels related to Huntington's disease.

  5. Step 5

    Final assessments and study completion

    At the end of the study period, final assessments are conducted to evaluate the overall effects of the medication.

    The study aims to determine changes in health markers from the beginning to the end of the study, including safety and efficacy outcomes.

Who can join the trial?

9 criteria

  • Must be a male or female who can walk and is aged 25 years or older.
  • Must be willing and able to give consent and follow all study rules.
  • Must have a confirmed diagnosis of **Huntington's Disease** with a specific genetic marker called **CAG repeat length** between 40 and 50. This can be checked through a lab test.
  • Must have a **UHDRS IS score** of 100. This is a score from a test that measures certain abilities in people with Huntington's Disease.
  • Must have a **UHDRS TFC score** of 13. This is another score from a test that measures daily living skills in people with Huntington's Disease.
  • Must have a score between 0.18 and 4.93 on a special index called the **HD prognostic index**. This index helps predict the progression of Huntington's Disease.
  • Women who can have children must agree to use very effective birth control methods while taking the study medication and for 6 months after stopping it. This includes women who are not yet menopausal or have not had surgery to prevent pregnancy.
  • Men who are sexually active and can father children must agree to use a condom during sex while taking the study medication and for 6 months after stopping it. This is to prevent passing the drug through semen.
  • For another group in the study, must have a **UHDRS TFC score** of 11 or 12, or a score of 13 with a **UHDRS IS score** of less than 100.

Who cannot join the trial?

8 criteria

  • Individuals who do not have a confirmed diagnosis of Huntington's Disease cannot participate. Huntington's Disease is a genetic disorder that affects the brain.
  • Participants must be within a specific age range, typically adults, to be eligible.
  • Both males and females are eligible, but certain health conditions or factors may exclude them.
  • Individuals who are considered part of a vulnerable population, such as those unable to give informed consent, may be excluded.
  • Participants must not have any other medical conditions or be taking medications that could interfere with the study.
  • Pregnant or breastfeeding women are usually excluded to avoid any potential risks to the baby.
  • Individuals with a history of severe allergic reactions to any of the study medications or similar drugs may be excluded.
  • Participants must not have participated in another clinical trial recently, as this could affect the study results.
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Investigated drugs

PTC518 is a medication being studied for its potential to treat Huntington's disease. The trial aims to assess the safety of this medication and its ability to lower the levels of a specific protein called total huntingtin (tHTT) in the blood. This protein is associated with the progression of Huntington's disease, and reducing its levels may help manage the condition.

What is already known about the treatment

PTC518 – PTC518 is an investigational medication currently being studied in clinical trials for its potential use in treating Huntington's Disease. It is administered orally in the form of tablets. The medication is in the Phase 2a stage of clinical trials, where its safety and effectiveness are being evaluated. PTC518 is designed to reduce the levels of the huntingtin protein in the blood, which is believed to play a role in the progression of Huntington's Disease. It falls under the pharmacological classification of small molecule drugs, which are typically used to target specific proteins or pathways in the body.

Investigated diseases

Huntington's Disease – Huntington's Disease is a genetic disorder that affects the brain, leading to the progressive breakdown of nerve cells. It typically begins in middle adulthood and is characterized by movement disorders, cognitive decline, and psychiatric symptoms. As the disease progresses, individuals may experience involuntary movements, difficulty with coordination, and changes in mood and behavior. Cognitive abilities, such as thinking and reasoning, gradually deteriorate, impacting daily functioning. The disease is caused by a mutation in the HTT gene, which leads to the production of an abnormal form of the huntingtin protein. Over time, the accumulation of this protein damages specific areas of the brain, leading to the symptoms observed in affected individuals.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IITrial ID2023-509835-26-00Protocol codePTC518-CNS-002-HDEstimated enrolment205 patientsSponsorPTC Therapeutics Inc.

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