Recruiting
Phase 3

Pridopidine

Sponsor:

Prilenia

Code:

NCT07609108

Conditions

Huntington Disease

Eligibility Criteria

Sex: All

Age: 23 - 65

Healthy Volunteers: Not accepted

Interventions

Pridopidine

Placebo

Study Details

Brief summary:

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.

Conditions

Huntington Disease

Study ID

NCT07609108

Start date

Jul 1, 2026

Status verified date

May, 2026

Completion date

Jun, 2030

Anticipated

Primary completion date

Jun, 2028

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 23 - 65

Healthy Volunteers: Not accepted

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 Design

Enrollment

400 participants

Anticipated

Allocation

Randomized

Intervention Model

Parallel Assignment

Primary purpose

Treatment

Interventions and Outcome Measures

Arms

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.

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.

Interventions

Pridopidine

Pridopidine hard gelatin capsule

Placebo

Matched placebo hard gelatin capsule

Primary outcome measure

  • Change in Composite Unified Huntington's Disease Rating Scale (cUHDRS) [ Time Frame: Change from Baseline to Week 52 ]

Central Contacts and Locations

Central contacts

Prilenia Medical Information

018575745755MedInfo@prilenia.com

Locations

University of California, San Diego

Recruiting

La Jolla, California, United States, 92037

Contacts

Alex Scott

858-249-0569als074@health.ucsd.edu

Hereditary Neurological Disease Centre

Recruiting

Wichita, Kansas, United States, 67226

Contacts

Gregory Suter

316-609-3020gregory@hndcentre.com

More Information

Sponsor

Prilenia

Last update posted

Aug 7, 2026

Last verified

May, 2026

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-10. This information was provided to ClinicalTrials.gov by Prilenia on 2026-08-07.