Pridopidine Phase 3 Study in Huntington's Disease (PRECISE-HD)

September 14, 2026 updated by: Prilenia

A Phase 3, Randomized, Double-blind, Placebo-controlled Study to Evaluate the Efficacy and Safety of Pridopidine in Participants With Huntington's Disease (HD)

The goal of this clinical trial is to learn if pridopidine can slow the clinical decline of Huntington's Disease (HD) in adult participants. It will also inform about the safety of pridopidine.

The main questions the study aims to answer are:

Does pridopidine slow the overall worsening of HD over 1 year? Does pridopidine slow the worsening of specific aspects of HD over 1 year, namely the clinical progression, the ability to perform daily life activities (functional capacity), the mind's ability to process information (cognition), working of the muscles (motor function), and quality of life?

Researchers will compare the drug pridopidine to a placebo (a look-alike substance that contains no drug) to see if pridopidine works better than placebo to treat HD. During the first year of the study, participants will have the same chance to receive either pridopidine or placebo.

Participants will:

Take 1 pridopidine or placebo capsule twice daily for 12 months. Visit the clinic 6 times within 1 year for checkups and tests.

All participants who complete this 1-year placebo-controlled study period will roll over into an additional 2-year study period during which all participants will receive pridopidine treatment, including participants who had received placebo during the first year. During this additional 2-year treatment period participants will visit the clinic a total of 6 times for checkups and tests.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

This Phase 3 study consists of two study periods, a randomized, double-blind, placebo-controlled 1-year study period and a 2-year open-label extension (OLE) period. The study assesses the effect of pridopidine 45 mg twice daily on HD in participants who are not using antidopaminergic medications (ADMs) at study start. Main objectives of the study will be to assess the effect of pridopidine on clinical progression of HD within 1 year and to evaluate the effect of pridopidine on functional capacity, cognition, motor function, quality of life (QoL), and speech in participants with HD within 1 year.

The target population in this study are adult participants (age 23-65, inclusive) with adult-onset HD (onset of signs and symptoms and a diagnosis ≥21 years of age). Eligible participants have not been using ADMs for at least 6 months prior to the screening visit. In case ADM treatment is deemed necessary by the treating physician during the study, specific ADMs and doses may be initiated. Female participants who are pregnant, planning to become pregnant or breastfeeding are not allowed to enter the study.

The treatment period will start with a 2-week titration period of once-daily treatment (1 capsule of pridopidine or placebo taken orally in the morning). From Day 15 onwards, all participants will take the study drug twice daily: in the morning and in the afternoon. Treatment will continue for an additional 50 weeks.

The placebo-controlled study period includes 6 in-clinic visits and 5 telephone visits (safety calls) during the 1-year treatment period.

The placebo-controlled study period will be followed by a 2-year OLE period. During the OLE period, all eligible participants will receive pridopidine. The OLE will consist of a 2-year treatment period, including an initial 2-week (re)titration period for all participants at pridopidine once daily and a maintenance period of 102 weeks with pridopidine twice daily. The blinding of the original treatment assignment will be maintained for all participants and study personnel during the OLE period.

A total of 6 in-clinic visits and 6 telephone visits (safety calls) are planned during the 2-year OLE period.

Study Type

Interventional

Enrollment (Estimated)

400

Phase

  • Phase 3

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

  • Belgium
      • Anderlecht, Belgium
        • Not yet recruiting
        • Hopital Erasme
      • Woluwe-Saint-Lambert, Belgium
        • Not yet recruiting
        • Cliniques universitaires Saint-Luc
  • Canada
    • Alberta
      • Calgary, Alberta, Canada
        • Not yet recruiting
        • University Of Calgary
      • Edmonton, Alberta, Canada
        • Not yet recruiting
        • University of Alberta
    • British Columbia
      • Vancouver, British Columbia, Canada
        • Not yet recruiting
        • University of British Columbia
    • Ontario
      • Toronto, Ontario, Canada
        • Not yet recruiting
        • North York General Hospital
    • Quebec
      • Montreal, Quebec, Canada
        • Not yet recruiting
        • Centre hospitalier de l'Université de Montréal (CHUM)
  • Czechia
      • Prague, Czechia
        • Not yet recruiting
        • Vseobecna fakultni nemocnice v Praze
  • France
      • Angers, France
        • Not yet recruiting
        • Centre Hospitalier Universitaire d'Angers
      • Créteil, France
        • Not yet recruiting
        • CHU Henri Mondor (APHP)
      • La Tronche, France
        • Not yet recruiting
        • Centre Hospitalier Universitaire Grenoble Alpes
      • Marseille, France
        • Not yet recruiting
        • Centre Hospitalier Regional De Marseille
  • Germany
      • Aachen, Germany
        • Not yet recruiting
        • Universitaetsklinikum Aachen AöR
      • Bochum, Germany
        • Not yet recruiting
        • Katholisches Klinikum Bochum gGmbH
      • Erlangen, Germany
        • Not yet recruiting
        • Universitätsklinikum Erlangen
      • Münster, Germany
        • Not yet recruiting
        • George-Huntington-Institut GmbH
      • Taufkirchen, Germany
        • Not yet recruiting
        • Isar Amper Klinikum
      • Ulm, Germany
        • Not yet recruiting
        • Universitaetsklinikum Ulm AöR
  • Italy
      • Bologna, Italy
        • Not yet recruiting
        • Azienda Unita Sanitaria Locale Di Bologna
      • Milan, Italy
        • Not yet recruiting
        • IRCCS Istituto Auxologico Italiano
      • Naples, Italy
        • Not yet recruiting
        • Azienda Ospedaliera Universitaria Federico II di Napoli
      • Padova, Italy
        • Not yet recruiting
        • Azienda Ospedale Università di Padova
      • Roma, Italy
        • Not yet recruiting
        • Fondazione Policlinico Universitario Agostino Gemelli IRCCS
      • San Giovanni Rotondo, Italy
        • Not yet recruiting
        • Casa Sollievo Della Sofferenza
  • Netherlands
      • Leiden, Netherlands
        • Not yet recruiting
        • Leids Universitair Medisch Centrum (LUMC)
  • Poland
      • Krakow, Poland
        • Not yet recruiting
        • Krakowska Akademia Neurologii Sp. z o.o.
      • Warsaw, Poland
        • Not yet recruiting
        • Wojskowy Instytut Medycyny Lotniczej
  • Portugal
      • Coimbra, Portugal
        • Not yet recruiting
        • Unidade Local De Saude De Coimbra E.P.E
      • Lisbon, Portugal
        • Not yet recruiting
        • Unidade Local De Saude De Santa Maria E.P.E.
      • Porto, Portugal
        • Not yet recruiting
        • Unidade Local De Saude De Santo Antonio E.P.E.
      • Torres Vedras, Portugal
        • Not yet recruiting
        • CNS Saude Lda.
  • Spain
      • Barakaldo, Spain
        • Not yet recruiting
        • Hospital Universitario de Cruces
      • Barcelona, Spain
        • Not yet recruiting
        • Hospital de La Santa Creu i Sant Pau
      • Madrid, Spain
        • Not yet recruiting
        • Hospital Universitario Ramon y Cajal
      • Oviedo, Spain
        • Not yet recruiting
        • Hospital Universitario Central de Asturias
      • Seville, Spain
        • Not yet recruiting
        • Hospital Universitario Virgen del Rocío
  • United Kingdom
      • Aberdeen, United Kingdom
        • Not yet recruiting
        • NHS Grampian
      • Birmingham, United Kingdom
        • Not yet recruiting
        • Birmingham and Solihull Mental Health Foundation NHS Trust
      • Cardiff, United Kingdom
        • Not yet recruiting
        • Cardiff University
      • Liverpool, United Kingdom
        • Not yet recruiting
        • The Walton Centre NHS Foundation Trust
      • Newcastle upon Tyne, United Kingdom
        • Not yet recruiting
        • CNTW NHS Foundation Trust
  • United States
    • Alabama
      • Birmingham, Alabama, United States, 35294
        • Not yet recruiting
        • The University of Alabama at Birmingham
    • California
      • La Jolla, California, United States, 92037
        • Recruiting
        • University of California, San Diego
        • Contact:
      • Los Angeles, California, United States, 90095
        • Not yet recruiting
        • UCLA Medical Center
      • Sacramento, California, United States, 95817
        • Not yet recruiting
        • UC Davis Medical Center
    • District of Columbia
      • Washington D.C., District of Columbia, United States, 20007
        • Not yet recruiting
        • Georgetown University
    • Florida
      • Boca Raton, Florida, United States, 33486
        • Not yet recruiting
        • University of Miami-U Health Boca Raton
      • Gainesville, Florida, United States, 32608
        • Not yet recruiting
        • University of Florida (Norman Fixel Institute for Neurological Diseases)
    • Illinois
      • Chicago, Illinois, United States, 60611
        • Not yet recruiting
        • Northwestern University
      • Chicago, Illinois, United States, 60612
        • Not yet recruiting
        • Rush University Medical Center
    • Kansas
      • Kansas City, Kansas, United States, 66103
        • Not yet recruiting
        • University of Kansas Medical Center
      • Wichita, Kansas, United States, 67226
        • Recruiting
        • Hereditary Neurological Disease Centre
        • Contact:
    • Maryland
      • Baltimore, Maryland, United States, 60612
        • Not yet recruiting
        • Johns Hopkins University
    • Massachusetts
      • Charlestown, Massachusetts, United States, 02129
        • Not yet recruiting
        • Massachusetts General Hospital
    • Minnesota
      • Golden Valley, Minnesota, United States, 55427
        • Not yet recruiting
        • Struthers Parkinson's Center / Health Partners Institute
    • New York
      • New York, New York, United States, 10032
        • Not yet recruiting
        • Columbia University
    • North Carolina
      • Durham, North Carolina, United States, 27705
        • Not yet recruiting
        • Duke University
    • Ohio
      • Cincinnati, Ohio, United States, 45219
        • Not yet recruiting
        • University of Cincinnati
      • Cleveland, Ohio, United States, 44195
        • Not yet recruiting
        • Cleveland Clinic
      • Columbus, Ohio, United States, 43221
        • Recruiting
        • The Ohio State University
    • Oregon
      • Portland, Oregon, United States, 97239
        • Not yet recruiting
        • Oregon Health and Science University (OHSU)
    • Tennessee
      • Nashville, Tennessee, United States, 37212
        • Recruiting
        • Vanderbilt University Medical Center
    • Texas
      • Houston, Texas, United States, 77030
        • Not yet recruiting
        • UT Health, Houston, McGovern Medical School
    • Vermont
      • Burlington, Vermont, United States, 05401
        • Not yet recruiting
        • University of Vermont Medical Center
    • Washington
      • Kirkland, Washington, United States, 98034
        • Not yet recruiting
        • EvergreenHealth Research Department
      • Seattle, Washington, United States, 98195
        • Recruiting
        • University of Washington

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Adult-onset HD (onset of signs and symptoms and a clinical diagnosis at ≥21 years of age).
  • A diagnosis based on clinical features and the presence of ≥40 CAG repeats in the huntingtin (HTT) gene confirmed by historical laboratory quanitified results or by a diagnostic test at Screening.
  • Diagnostic confidence level (DCL) of 4 (DCL=4 unequivocal motor signs, ≥99% confidence) on the standardized motor exam Total Motor Score (TMS).
  • Total Functional Capacity (TFC) score of ≥7 at Screening and Baseline.
  • Cytosine-Adenine-Guanine (CAG)-Age Product (CAP)100 score ≥95 at Screening.
  • Independence Scale (IS) score ≤90% at Screening.
  • Total Motor Score (TMS) of ≥20 at Screening and Baseline.
  • Not using ADMs (VMAT2i and neuroleptics/antipsychotics) for at least 6 months prior to Screening visit. Importantly, it is not encouraged to discontinue the participants' ADM treatment solely for enrollment in the current trial.

Exclusion Criteria:

  • Clinically significant cardiovascular disease (e.g. QTcF >450 msec [males] or >470 msec [females], arrhythmias, uncontrolled atrial fibrillation, or congenital long QT syndrome), seizure history ≤5 years, significant neurological disorders (e.g. intracranial pathology or cerebrovascular events), active/recent malignancy (unless localized and resolved), or any serious or uncontrolled systemic disease (e.g. hepatic, renal, respiratory, endocrine, infectious [HBV, HCV, HIV], or psychiatric) that may pose safety risk or interfere with participation.
  • Severe hepatic or renal impairment.
  • Any mutant huntingtin (mHTT) lowering therapy in the past year.
  • Medications that prolong QT interval, taken within 4 weeks of the baseline visit.
  • Use of pridopidine within 6 weeks or 5 half-lives before the screening visit.
  • Previous participation in intracranial gene therapy study.
  • Laboratory values that fall outside of the central laboratory's reference range at Screening and are considered clinically significantly abnormal by the Investigator and affect the participant's suitability to participate in the study or put the participant at risk if he/she enters the study in the Investigator's opinion.
  • Female participants who are pregnant, planning to become pregnant or breastfeeding.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Quadruple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Pridopidine
During the titration period (2 weeks), pridopidine 45 mg capsules will be taken orally once daily (in the morning) for 2 weeks. Afterwards, pridopidine 45 mg capsules will be taken orally twice daily (in the morning and in the afternoon; 7-10 hours apart) for 50 weeks.
Drug: Pridopidine
Pridopidine hard gelatin capsule
Placebo Comparator: Placebo
During the titration period (2 weeks), matched placebo hard gelatin capsules will be taken once daily (in the morning) for 2 weeks. Afterwards, placebo capsules will be taken twice daily (in the morning and in the afternoon; 7-10 hours apart) for 50 weeks.
Drug: Placebo
Matched placebo hard gelatin capsule

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in Composite Unified Huntington's Disease Rating Scale (cUHDRS)
Time Frame: Change from Baseline to Week 52

cUHDRS is a combined score to assess disease progression in HD. It includes TFC, TMS, SDMT, and SWR:

Total Functional Capacity (TFC) tests the capacity to maintain daily living, finances, care level, occupation. Higher score = better outcome. Best score=13. Worst score=0.

Total Motor Score (TMS) assesses motor features (oculomotor, dysarthria, chorea, dystonia, gait, postural stability). Higher score = worse outcome. Best score=0. Worst score= 124.

Stroop Word Reading (SWR) measures attention and mental flexibility. Participant reads names of colors printed in black ink. Scores reflect correct responses in 45 sec. Higher score = better outcome. Best score=100. Worst score=0.

Symbol Digit Modalities Test (SDMT) tests psychomotor speed and working memory. Participant has 90 sec to match numbers with symbols. Scores = correct answers in 90 sec. Higher score = better outcome. Best score=120. Worst score=0.

Total integrated cUHDRS scale range: -7.6 to 24.8. The higher, the better.
Change from Baseline to Week 52

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in Total Functional Capacity (TFC) score
Time Frame: Change from Baseline to Week 52
Total Functional Capacity (TFC) tests the capacity to maintain domestic chores, activities of daily living, finances, care level, and occupation. Scores from 0 - 13. Higher score = better outcome.
Change from Baseline to Week 52
Change in Quantitative Motor (Q-Motor) Finger Tapping Inter-Onset Interval (FT-IOI) mean
Time Frame: Change from Baseline to Week 52
Quantitative (Q)-motor is a clinical assessment of fine motor skills that are crucial for daily activities. It is based on the application of pre-calibrated and temperature-controlled force transducers and 3-dimensional position sensors. Higher score = worse outcome.
Change from Baseline to Week 52
Change in Stroop Word Reading (SWR) score
Time Frame: Change from Baseline to Week 52
Stroop Word Reading (SWR) measures attention and mental flexibility. Participant reads names of colors printed in black ink. Scores reflect correct responses in 45 sec. Higher score = better outcome.
Change from Baseline to Week 52

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Prilenia

Collaborators

Ferrer Internacional S.A.

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

July 1, 2026

Primary Completion (Estimated)

June 1, 2028

Study Completion (Estimated)

June 1, 2030

Study Registration Dates

First Submitted

May 20, 2026

First Submitted That Met QC Criteria

May 20, 2026

First Posted (Actual)

May 27, 2026

Study Record Updates

Last Update Posted (Actual)

September 17, 2026

Last Update Submitted That Met QC Criteria

September 14, 2026

Last Verified

May 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • PL101-HD302/ FNP253-CT-2502
  • 2026-526093-16-00 (Ctis)

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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