Pridopidine Phase 3 Study in Huntington's Disease

NCT07609108 | Not Yet Recruiting Phase 3 DMC FDA Drug

• 2 other identifiers: PL101-HD302/ FNP253-CT-25022026-526093-16-00
• Study Type: interventional
• Target: 400
• Locations: 0 countries
• Sites: N/A

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

Outcome Measures

Primary Outcomes (1)

• Change in Composite Unified Huntington's Disease Rating Scale (cUHDRS)

  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 Outcomes (3)

• Change in Total Functional Capacity (TFC) score

  Change from Baseline to Week 52

• Change in Quantitative Motor (Q-Motor) Finger Tapping Inter-Onset Interval (FT-IOI) mean

  Change from Baseline to Week 52

• Change in Stroop Word Reading (SWR) score

  Change from Baseline to Week 52

Study Arms (2)

Pridopidine

EXPERIMENTAL

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

Placebo

PLACEBO COMPARATOR

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

Interventions

Pridopidine DRUG

Pridopidine hard gelatin capsule

Pridopidine

Placebo DRUG

Matched placebo hard gelatin capsule

Placebo

Eligibility Criteria

• Age: 23 Years - 65 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• 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.

You may not qualify if:

• 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.

Sponsors & Collaborators

• Prilenia: lead
• Ferrer Internacional S.A.: collaborator

MeSH Terms

Conditions

Huntington Disease

Interventions

pridopidine

Condition Hierarchy (Ancestors)

Basal Ganglia Diseases; Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Dementia; Chorea; Dyskinesias; Movement Disorders; Heredodegenerative Disorders, Nervous System; Neurodegenerative Diseases; Genetic Diseases, Inborn; Congenital, Hereditary, and Neonatal Diseases and Abnormalities; Cognition Disorders; Neurocognitive Disorders; Mental Disorders

Central Study Contacts

Prilenia Medical Information Executive Director Clinical Operations

CONTACT

018575745755; MedInfo@prilenia.com

Study Design

• Study Type: interventional
• Phase: phase 3
• Allocation: RANDOMIZED
• Masking: QUADRUPLE
• Who Masked: PARTICIPANT, CARE PROVIDER, INVESTIGATOR, OUTCOMES ASSESSOR
• Masking Details: All participants, site staff, Sponsor, CRO and vendors involved with the study will remain blinded to treatment assignments until the database is locked and the study unblinded.
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Model Details: Randomized (1:1), double-blind, placebo-controlled 1-year study period, followed by a 2-year open-label extension (OLE) period. During the OLE, all participants will receive pridopidine.

Study Record Dates

• First Submitted: May 20, 2026
• First Posted: May 27, 2026
• Study Start: June 1, 2026
• Primary Completion (Estimated): June 1, 2028
• Study Completion (Estimated): June 1, 2030
• Last Updated: June 2, 2026

Record last verified: 2026-05