Skip to content
Clinical Trials – home

Rare diseases

Investigational molecules

Locations

Our offerNewsroom

RecruitingRare disease

Efficacy and safety of votoplam in adults with Huntington’s disease: a randomized, double‑blind, placebo‑controlled Phase 3 trial

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

Huntington’s Disease is a rare, inherited brain disorder that causes problems with movement, thinking and mood. The study looks at a new oral tablet called votoplam (code name HTT227) compared with a placebo. The medication is taken by mouth as a tablet.

The purpose of the study is to see whether votoplam can slow the progression of Huntington’s Disease. Participants will be randomly assigned to receive either the study drug or the placebo, and neither the participants nor the researchers will know which one is given. The study lasts about three years, with regular visits to check health, perform simple tests, and collect blood samples.

During the visits, doctors will use a questionnaire called the Unified Huntington’s Disease Rating Scale to track changes in movement, thinking and daily abilities. Blood will be checked for a protein called mutant huntingtin (a faulty version of a normal brain protein), and safety will be monitored by recording any side effects. The information collected will help understand if the drug is safe and helpful.

The research process

The trial runs in 7 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Baseline assessment

    After joining the study, a complete health evaluation is performed. this includes physical measurements, neurological examinations, and collection of blood samples to establish a starting point for later comparisons.

  2. Step 2

    Randomization

    Based on a computer‑generated system, you are assigned to receive either votoplam (the active drug) or a matching placebo tablet. the assignment is concealed from both you and the study team.

  3. Step 3

    Receive study medication

    You will be given tablets that look identical regardless of assignment. each tablet contains votoplam at a dose of 00 mg (or no active ingredient in the case of the placebo). the tablets are taken by mouth.

  4. Step 4

    Medication administration

    The tablets are taken according to the schedule provided by the study staff, typically once each day. the medication is continued for the entire treatment period, which lasts up to 36 months.

  5. Step 5

    Regular clinic visits

    Throughout the 36‑month period you will attend scheduled visits at the clinic. visits occur at baseline and then approximately every 3 to 6 months (for example, at month 3, month 6, month 12, month 18, month 24, month 30, and month 36). during each visit you will undergo the same assessments performed at baseline, allowing the study to track changes over time.

  6. Step 6

    Safety monitoring

    At every visit you will be asked about any new symptoms or health problems. any adverse events, whether mild or serious, are recorded and reviewed by the study physicians.

  7. Step 7

    Final evaluation

    At the month 36 visit a comprehensive assessment is performed. the results are compared with the baseline data to determine the effect of votoplam on the progression of huntington’s disease.

Who can join the trial?

7 criteria

  • Signed informed consent must be obtained before joining the study; this means you give a written agreement after understanding what the trial involves.
  • You must be able to walk (referred to as ambulatory) and be between 21 and 70 years old on the day you sign the consent, regardless of gender.
  • You need a confirmed genetic diagnosis of Huntington’s disease with a CAG repeat length of 40 or higher; this is a specific part of the gene that is repeated many times and indicates the disease.
  • Your scores on the disease‑specific tests must meet all of the following:
    • UHDRS IS score of 90 or more (the Independence Scale measures how independent you are).
    • UHDRS TFC score exactly 13 (the Total Functional Capacity assesses daily functioning).
    • UHDRS TMS score between 7 and 25, inclusive (the Total Motor Score evaluates movement problems).
    • CAP100 score of 70 or higher; this score is calculated using your age and CAG repeat length to estimate disease progression.

Who cannot join the trial?

9 criteria

  • Having had gene therapy, cell transplantation, or any other experimental brain surgery to treat Huntington’s disease – these are special procedures that change genes or add cells and are still being tested.
  • Showing signs of an active hepatitis infection in blood tests, such as:
    • Positive anti‑HBc IgM or anti‑HBc IgG together with a positive hepatitis B surface antigen (HBsAg) or detectable hepatitis B virus DNA – indicating current hepatitis B infection.
    • Positive hepatitis C antibody test confirmed by detectable hepatitis C RNA – indicating current hepatitis C infection.
    • Having an immune‑system disorder, including a positive test for HIV (human immunodeficiency virus).
    • Being a woman who could become pregnant (women of childbearing potential) unless she has had surgery that removes both ovaries (bilateral oophorectomy) or both the uterus and ovaries (total hysterectomy) at least six weeks before the study, or unless she is using a highly effective birth‑control method (failure rate less than 1 % per year) during the study and for eight months after stopping the study drug.
    • Being pregnant or breastfeeding (nursing) at any time during the study.
    • Having a history or current diagnosis of heart problems that could be unsafe, such as:
      • Significant heart rhythm problems (arrhythmias) like sustained ventricular tachycardia (a fast, dangerous heartbeat originating from the lower chambers of the heart).
      • Second‑ or third‑degree atrioventricular (AV) block without a pacemaker (a condition where electrical signals between the heart’s chambers are severely delayed or blocked).
      • Family history of long QT syndrome (a genetic condition that can cause dangerous heart rhythms) or Torsade de Pointes (a specific type of fast, irregular heartbeat).
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.

RecruitingNot yet 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

HTT227 is an experimental oral tablet being tested in people with Huntington’s disease. It contains the active ingredient votoplam, which is designed to target the underlying genetic cause of the disease. In this trial, participants take the tablet each day to see if it can slow the worsening of symptoms compared with a control group. Researchers will watch how the drug affects movement, thinking, and daily function by measuring changes in a standard rating scale. The study also looks at safety, checking for any side effects while participants use the medication.

What is already known about the treatment

votoplam - Votoplam is taken as an oral tablet that patients swallow with water. It is currently an investigational orphan drug being studied in a Phase 3 trial for Huntington’s disease. The medication is designed to lower the amount of the abnormal huntingtin protein that causes the disease, acting at the genetic level to reduce its production. It is classified as a disease‑modifying therapy that works through antisense technology to silence mutant huntingtin.

Investigated diseases

Huntington disease - Huntington disease is a genetic brain disorder that causes a gradual loss of coordination and mental abilities. It usually starts in adulthood and slowly worsens over many years. Early signs include subtle changes in mood, thinking, and movement. As the disease advances, involuntary jerking movements (chorea) become more noticeable, and coordination becomes increasingly difficult. Cognitive decline progresses, affecting memory and decision‑making, while emotional changes such as irritability or depression may intensify. Over time the combination of motor, cognitive, and psychiatric symptoms leads to increasing dependence on care.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2025-522227-99-00Protocol codeCHTT227A12301Estimated enrolment815 patientsSponsorNovartis Pharma AG

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.