AuthorisedTherapeutic confirmatory (Phase III)Interventional

A Phase 3, Randomized, Double-blind, Placebo-controlled Study to Evaluate the Efficacy and Safety of Pridopidine in Participants with Huntington’s disease (HD).

Huntington’s disease is an inherited condition that gradually affects movement, memory, and day-to-day abilities. This study is testing whether a medicine called pridopidine can help slow down these changes and keep people living independently for longer. Participants take either pridopidine or a dummy treatment (placebo) each day for 52 weeks (one year). A placebo looks identical to the real medicine but contains no active ingredients, allowing scientists to see whether the drug truly works. Over the course of the year, study doctors monitor your overall health, movement, and thinking skills through regular check-ups and simple tests. Because this is a Phase 3 trial, it is one of the final stages of research before a medicine can be approved for general use. Taking part is completely voluntary, and you can stop at any time without losing your regular NHS care.

At a glance

Status

Authorised

Phase

Therapeutic confirmatory (Phase III)

Sponsor

Ferrer Internacional S.A., Prilenia Therapeutics B.V.

Enrolment target

188

Start

12 Oct 2026

Huntington’s disease (HD).

What is this study about?

Huntington’s disease is a genetic condition that damages nerve cells in the brain over time. This damage causes difficulties with movement, changes in mood, and challenges with thinking and planning. At present, there are medicines to manage some individual symptoms, but there are no approved treatments that slow down the overall progression of the condition.

Pridopidine is an experimental medicine designed to protect brain cells from stress and damage. Early research suggests it may help support the way nerve cells communicate with each other. This Phase 3 trial aims to confirm whether taking pridopidine over 52 weeks can help people retain their physical independence, coordination, and thinking abilities better than a dummy pill.

Phase 3 trials are large, late-stage studies designed to gather strong evidence about whether a new medicine works and how safe it is. If the results are positive, the evidence gathered from this study could lead to the medicine being officially approved for use in the UK and worldwide, potentially offering a valuable new treatment option for families affected by Huntington’s disease.

Key takeaways

Tests whether the study drug pridopidine can slow down Huntington's disease symptoms.
Open to adults aged 18 and older diagnosed with Huntington's disease.
Half of the participants receive pridopidine, and half receive a dummy pill (placebo).
Involves taking daily capsules and attending regular clinic visits for one year.
Participation is voluntary, and you may leave the study at any time.

Who may be eligible?

This study is open to men and women aged 18 and older who have been diagnosed with Huntington’s disease. Participants generally need to have noticeable symptoms of the condition but still be able to manage many of their daily activities, either independently or with some support.

To ensure it is safe for you to take part, the medical team will review your health history and any medications you currently take. People with certain serious medical conditions, such as severe heart or kidney problems, or those currently taking part in another drug trial, may not be able to join.

Because taking part involves regular visits to a specialist hospital or research clinic, having a family member, partner, or study partner who can attend visits with you is often recommended and helpful.

Could this study suit you?

Answer these quick questions to see if you may be eligible. This is a guide only — the research team makes the final call.

I am aged 18 or older.
I have a confirmed clinical diagnosis of Huntington’s disease.
I can attend regular hospital visits over a 52-week period.
I am willing to take study capsules every day as instructed.
I have a family member, partner, or friend who can support me at appointments if needed.

Answer every question to see your result.

What does participation involve?

Taking part in this study lasts for about 52 weeks (one full year). You will be randomly chosen to receive either the study medicine (pridopidine) or an inactive dummy pill (placebo). Neither you nor your study doctor will know which one you are taking until the study ends. You will take your assigned study capsules daily by mouth.

Throughout the year, you will visit the study clinic every few months for health checks. During these appointments, the team will check your blood pressure, take blood and urine samples, and monitor your general health. You will also complete gentle assessments, such as quick finger-tapping exercises on a computer to measure coordination, reading exercises, and memory games. The doctors will also ask how well you are managing daily routines at home, such as managing finances, driving, or personal care.

Potential risks and benefits

You may not get any direct personal benefit from taking part, especially if you are placed in the group receiving the dummy pill. However, if pridopidine works, it could help support your movement and daily function, and your participation will help doctors find better treatments for future generations. Like all medicines, pridopidine may cause side effects, which your study team will monitor very closely. You are never locked into the trial; you have the legal and medical right to leave at any point, for any reason, without it affecting your standard medical care.

Locations (9)

Some site locations are approximate. We're improving this — please verify with the trial team before travelling.

—
Unverified
Spain
—
Unverified
Italy
—
Unverified
Portugal
—
Unverified
Poland
—
Unverified
France
—
Unverified
Netherlands
—
Unverified
Germany
—
Unverified
Belgium
—
Unverified
Czechia

Common questions

What is a placebo and why is it used?

A placebo is a dummy treatment that looks and tastes identical to the real medicine but contains no active ingredients. It helps researchers prove whether any improvements or side effects are truly caused by pridopidine.

Will I have to pay to take part?

No. The study medication, clinic visits, and all trial tests are provided free of charge. Travel costs and reasonable expenses are usually reimbursed.

Can I carry on taking my usual medicines?

In most cases, yes. The study doctor will review all your regular prescriptions and supplements during screening to make sure they are safe to take alongside the trial drug.

How often will I need to visit the hospital?

You will usually visit the clinic every few weeks at the beginning, and then every month or two once settled, for a total of around a year.

What happens if I change my mind?

You can leave the trial at any time. Simply tell your study doctor. Leaving will not change your relationship with your medical team or affect your normal NHS care.