Who may be eligible for the A Safety and Pharmacokinetics Trial of VO659 in SCA1, SCA3 and HD trial?

Main Inclusion Criteria: * Provide written informed consent (signed and dated). Patients should be assessed for their ability to give informed consent using the Evaluation to Sign Consent tool. * Is ≥25 and ≤60 years of age inclusive, of any gender, at the time of signing the informed consent. * Have SCA1, SCA3 or HD meeting one of the following criteria: 1. SCA1 and SCA3: mild to moderate disease with a Scale for Assessment and Rating of Ataxia (SARA) score of ≥3 and ≤18 2. HD: early manifest, Stage I disease with a Total Functional Capacity (TFC) Score of ≥11 and ≤13 and a Unified Huntington's Disease Rating Scale (UHDRS) Diagnostic Confidence Level (DCL) of 4. * Have genetically confirmed disease, defined by increased cytosine, adenine, and guanine (CAG) repeat length in the disease-causing allele by direct DNA testing. For each indication the requirements are: 1. SCA1: ≥41 contiguous, uninterrupted CAG repeats in the ATXN1 gene 2. SCA3: ≥61 repeats in the ATXN3 gene 3. HD: ≥40 CAG repeats in the HTT gene. * Please note there will be additional inclusion criteria Main Exclusion Criteria: * Have any condition that would prevent participation in trial assessments. * Have one or more pathogenic mutation(s) in another polyQ disease gene, i.e., ATXN2, CACNA1A, ATXN7, TBP, AR, and ATN1, plus either ATXN3 and HTT (for patients with SCA1), ATXN1 and HTT (for participants with SCA3), or ATXN1 and ATXN3 (for participants with HD), in addition to the disease-causing mutation in the ATXN1 (patients with SCA1), ATXN3 (patients with SCA3) or HTT (patients with HD) gene. * Have clinical diagnosis of moderate or severe chronic migraines or history of the post-lumbar-puncture headache of moderate or severe intensity requiring hospitalisation or blood patch. * Have a brain, spinal or systemic disorder that would interfere with the LP process, CSF circulation, or safety assessments. * Have history of bleeding diathesis or coagulopathy, platelet count less than the lower limit of normal unless stable and assessed by the investigator and the Medical Monitor to be not clinically significant. * Have uncompensated cardiovascular disorder, any past or present cardiac arrhythmia, QTcF values on screening ECG of \>470 ms, familial history of long QT syndrome or sudden unexpected death. * Have a history of attempted suicide, suicidal ideation with a plan that required hospital admission and/or change in level of care within 12 months prior to screening. * Have medical, psychiatric, or other conditions that, in the judgement of the investigator, may compromise the patient's ability to understand the patient information sheet, to give informed consent, to comply with all trial requirements, or to complete the trial. * Prior treatment with an antisense oligonucleotide (including siRNA). * Pregnant or breast-feeding (lactating) women or women who plan to become pregnant or breast-feed during the trial. * Unable to undergo and tolerate MRI scans. * Please note there will be additional exclusion criteria

ClinicalTrials.gov record NCT05822908

A Safety and Pharmacokinetics Trial of VO659 in SCA1, SCA3 and HD

Record copied from ClinicalTrials.gov: Oct 10, 2026AI summaries generated: Sep 17, 2026

A Phase 1/2a, Open-label Trial to Investigate the Safety, Tolerability, Pharmacokinetics and Pharmacodynamics of Multiple Ascending Doses of Intrathecally Administered VO659 in Participants With Spinocerebellar Ataxia Types 1, 3 and Huntington's Disease

About this page. This page shows the study's official ClinicalTrials.gov record ↗, with added help to make it easier to understand. We explain medical terms, highlight key details in plain language, and suggest questions you may want to ask the study team.

The record is periodically copied from ClinicalTrials.gov and may lag behind changes. AI summaries are checked by software, not a clinician.Read moreShow less

The official record is written by the study sponsor and published on ClinicalTrials.gov. It may not always reflect the latest changes. Before making any decisions, please confirm important information with the study team and your own healthcare team.

Where you see "AI summary", AI was used to create a plain-language explanation and software checked it against the source. It has not been reviewed by a clinician, so it may contain mistakes or leave out important details.

StatusRecruitingThe study is currently enrolling participants. Only the study team can say whether a particular person can join.

Study typeInterventionalA study in which researchers assign participants to one or more interventions, such as a drug, procedure, device, behavioural programme or other approach, to measure their effects.

PhasePhase 1/2A study that combines safety and dose-finding (phase 1) with a first look at whether the treatment has an effect (phase 2).

Age25 years old to 60 years old

SexAll

LocationDenmark, France, Germany, Israel, Netherlands, United Kingdom

AI summaryWhat this study is about, in plain languageShow ▾Hide ▴

AI-written from the registry record, not the study's own wording. May contain errors or omissions. Check the registry text on this page and the original record ↗ before acting on it.

This phase 1/2a, first-in-human study gives multiple ascending doses of VO659 by lumbar (intrathecal) injection to people with SCA1, SCA3, or early Huntington's disease. It is open-label and measures safety, tolerability, and concentrations of the drug in cerebrospinal fluid and blood. Different cohorts receive different dose schedules; one cohort receives a single higher dose followed by long-term observation.

What it is studying. The trial tests the safety and tolerability of intrathecally administered VO659, measures drug concentrations in cerebrospinal fluid and plasma (pharmacokinetics), and explores pharmacodynamics.

What the researchers hope to learn. To evaluate safety and tolerability of multiple ascending intrathecal doses of VO659; to determine VO659 concentrations in cerebrospinal fluid and plasma; to characterize pharmacokinetics and to explore pharmacodynamics.

What this study is about

The study's own summary, as published on ClinicalTrials.gov. Underlined terms have a short explanation.

The goal of this first-in-human clinical trial is to assess the safety and tolerability of four doses of a new study drug called VO659 in people with genetic disorders called spinocerebellar ataxia type 1, type 3 or Huntington's disease. Another aim is to determine the concentrations of the study drug in the cerebral spinal fluid and blood after single and multiple doses. Study drug will be administered by lumbar intrathecal bolus injections.

Interventions being studied

Being studied in this trial does not mean the treatment or procedure is approved or available for this condition.

Drug: VO659

Eligibility

The criteria exactly as listed on ClinicalTrials.gov. Only the study team can say whether they apply to you.

Inclusion criteria

Main Inclusion Criteria:
Provide written informed consent (signed and dated). Patients should be assessed for their ability to give informed consent using the Evaluation to Sign Consent tool.
Is ≥25 and ≤60 years of age inclusive, of any gender, at the time of signing the informed consent.
Have SCA1, SCA3 or HD meeting one of the following criteria:
SCA1 and SCA3: mild to moderate disease with a Scale for Assessment and Rating of Ataxia (SARA) score of ≥3 and ≤18
HD: early manifest, Stage I disease with a Total Functional Capacity (TFC) Score of ≥11 and ≤13 and a Unified Huntington's Disease Rating Scale (UHDRS) Diagnostic Confidence Level (DCL) of 4.
Have genetically confirmed disease, defined by increased cytosine, adenine, and guanine (CAG) repeat length in the disease-causing allele by direct DNA testing. For each indication the requirements are:
SCA1: ≥41 contiguous, uninterrupted CAG repeats in the ATXN1 gene
SCA3: ≥61 repeats in the ATXN3 gene
HD: ≥40 CAG repeats in the HTT gene.
Please note there will be additional inclusion criteria
Main

Exclusion criteria

Have any condition that would prevent participation in trial assessments.
Have one or more pathogenic mutation(s) in another polyQ disease gene, i.e., ATXN2, CACNA1A, ATXN7, TBP, AR, and ATN1, plus either ATXN3 and HTT (for patients with SCA1), ATXN1 and HTT (for participants with SCA3), or ATXN1 and ATXN3 (for participants with HD), in addition to the disease-causing mutation in the ATXN1 (patients with SCA1), ATXN3 (patients with SCA3) or HTT (patients with HD) gene.
Have clinical diagnosis of moderate or severe chronic migraines or history of the post-lumbar-puncture headache of moderate or severe intensity requiring hospitalisation or blood patch.
Have a brain, spinal or systemic disorder that would interfere with the LP process, CSF circulation, or safety assessments.
Have history of bleeding diathesis or coagulopathy, platelet count less than the lower limit of normal unless stable and assessed by the investigator and the Medical Monitor to be not clinically significant.
Have uncompensated cardiovascular disorder, any past or present cardiac arrhythmia, QTcF values on screening ECG of >470 ms, familial history of long QT syndrome or sudden unexpected death.
Have a history of attempted suicide, suicidal ideation with a plan that required hospital admission and/or change in level of care within 12 months prior to screening.
Have medical, psychiatric, or other conditions that, in the judgement of the investigator, may compromise the patient's ability to understand the patient information sheet, to give informed consent, to comply with all trial requirements, or to complete the trial.
Prior treatment with an antisense oligonucleotide (including siRNA).
Pregnant or breast-feeding (lactating) women or women who plan to become pregnant or breast-feed during the trial.
Unable to undergo and tolerate MRI scans.
Please note there will be additional exclusion criteria

Study description and what participation involves

The study's detailed description, as published on ClinicalTrials.gov.

Show the detailed description from the registry

Spinocerebellar ataxia types 1 and 3 (SCA1 and SCA3), as well as Huntington's disease (HD) are severely debilitating, monogenic, neurodegenerative diseases that presently have no treatments to slow or stop clinical progression. Preclinical data suggest that VO659 may be a disease-modifying therapy in these disorders through its binding to the expansion of CAG repeats in the RNA transcripts of the causative genes, thus interfering with RNA translation and reducing the intracellular level of the harmful mutant proteins. The present trial is the first-in-human (FiH) evaluation of VO659. This is an open-label, multiple ascending dose, multi-centre phase 1/2a trial investigate the safety, tolerability and pharmacokinetics and explore the pharmacodynamics of intrathecally administered study drug VO659. The trial population comprises generally ambulatory participants with mild to moderate SCA1 or SCA3, or early manifest HD. Participants are assigned to dose-ascending treatment cohorts based on the order of enrolment. Dose-escalation is planned in up to five dose levels. Dose-level cohorts one and two will comprise participants with SCA3 only, and from dose-level cohorts three onwards participants with SCA1, SCA3 and HD will be enrolled. The total duration of trial participation for each participant in Dose-level Cohorts 1-3 is up to approximately 45 weeks, consisting of a screening period of up to 6 weeks, a 14-week dosing period, and a 25-week post-dosing period. The total duration of trial participation for each participant in Dose-level Cohort 4 is up to approximately 58 weeks, consisting of a screening period of up to 7 weeks, a 26-week dosing period, and a 25-week post dosing period. The total duration of trial participation for each participant in Dose-level Cohort 5 is up to approximately 58 weeks, consisting of a screening period of up to 7 weeks, a single dosing followed by a 51-week period of non-dosing, observational visits (split into a 26-week 'dosing period' and a 25-week 'post-dosing period' for consistency in the SoA with Dose-level Cohort 4).

AI summaryWhat participation may involve, in plain languageShow ▾Hide ▴

AI-written from the registry record, not the study's own wording. May contain errors or omissions. Check the registry text on this page and the original record ↗ before acting on it.

Participants receive VO659 by lumbar intrathecal injection; some cohorts get multiple doses, one cohort is a single dose, and Cohort 4 uses random assignment between two dosing regimens. They will have repeated lumbar punctures for dosing and cerebrospinal fluid (CSF) collection, blood draws for drug levels, MRI scans, ECGs and routine safety blood tests, plus regular clinic visits for monitoring. Participation includes a screening assessment (including assessment of ability to consent), a dosing period and a post‑dosing follow‑up period; total time in the trial varies by cohort and can span many months (up to about 58 weeks). Certain people will be excluded for safety reasons (for example pregnancy, specific heart, bleeding or psychiatric conditions, inability to tolerate MRI or lumbar puncture).

How the study is structured. Open-label, randomized, interventional trial using a sequential, dose-escalation approach. Participants are assigned to dose cohorts and receive VO659 by lumbar intrathecal injection according to their cohort (some cohorts receive repeated injections over weeks; one cohort a single injection followed by observation). Study staff collect cerebrospinal fluid and blood samples and perform safety monitoring including MRI and standard labs during follow-up lasting about 42–58 weeks depending on cohort.

Questions you could ask

These questions are suggestions for a conversation with the study team or your own clinician, not advice.

This is an early-phase study, mainly about safety and dose. What is already known about this treatment?
The listed sites are in Denmark, France, Germany, Israel, Netherlands, United Kingdom. Is any of them reachable for me, and does the study help with travel?
Which of the eligibility criteria would need to be checked with tests before I could join?

More on spinocerebellar ataxia

Clinical trials30 trials listed for spinocerebellar ataxiaEvery trial the registry lists for spinocerebellar ataxia, with recruitment status, phase and sites, updated from ClinicalTrials.gov.See all trials →Research updatesWhat changed in spinocerebellar ataxia researchLatest monthly update: September 2026. Includes: NBP trial result. New research summarized each month in plain language, with links to every source paper.Read the latest update →

Important dates

Study start: Feb 14, 2023
Primary completion: Apr 1, 2028 (estimated)
Study completion: Oct 15, 2028 (estimated)
Target enrollment: 68 participants (estimated)
Last updated on registry: Aug 19, 2026
Data verified: Oct 10, 2026

Sponsor and research team

The lead sponsor funds and oversees the trial. A pharmaceutical or biotech company sponsor typically means the study is testing that company's drug or device; a hospital, university, or government agency usually indicates investigator-initiated or publicly funded research.

Lead sponsor: Vico Therapeutics B. V.

Central study contact

If you're interested in participating, the central contact can answer general questions about the study — including eligibility requirements and how to find a recruiting site near you. Actual eligibility is determined by the site's medical team.

Chief Medical Officer 📞 +31 71 2036800 ✉ info@vicotx.com

Participating sites (14)

Filter by country:

RigshospitaletRecruiting
Copenhagen · Denmark
- Lena Hjermind, Dr.
Centre Hospitalier Universitaire dÁngersRecruiting
Angers · France
- Christophe Verny, Prof.
CHU Gui de Chauliac Montpellier- Expert Center of Neurogenetic diseases, Department of NeurologyRecruiting
Montpellier · France
- Cecilia Marelli, Dr.
Universtiry Hospitals Pitie Salpetriere - Charles foix - ParisRecruiting
Paris · France
- Alexandra Durr, Prof. Dr.
Katholisches Klinikum BochumRecruiting
Bochum · Germany
- Carsten Saft, Prof.
Deutsches Zentrum fur Neurodegenerative Erkrankungen (DZNE)Recruiting
Bonn · Germany
- Jennifer Faber, Dr.
Universitatsklinikum Essen - NeurologieRecruiting
Essen · Germany
- Tim Hagenacker, Prof.
Universitatsklinikum TübingenRecruiting
Tübingen · Germany
- Ludger Scholz, Prof Dr.
Meir Medical CenterRecruiting
Kfar Saba · Israel
- Nirit Lev, Dr.
Sourmansky Medical CenterRecruiting
Tel Aviv · Israel
- Tanya Gurevich, Prof.

Terms used on this page · explanations by MedicalUpdates.ai

first-in-human: The first study in which a treatment is given to people. Safety is the main question and the number of participants is usually small.
study drug: A treatment that is being tested and has not been approved for this use. It may be approved for a different condition. Being studied does not mean it works or is available outside the study.
intrathecal: Given by injection into the fluid around the spinal cord, usually through a lumbar puncture.
Inclusion Criteria: The conditions a person must meet to be considered for the study, for example a confirmed diagnosis, an age range or a test result.
written informed consent: The process of explaining a study, including its risks and what participation involves, so that a person can decide freely whether to take part. Consent is usually documented in writing, and a participant can choose to leave the study later.
QTcF: A recording of the heart's electrical activity. QTc is one measurement from it; some drugs are avoided if it is prolonged.
prior to screening: The checks done before enrolment to see whether a person qualifies, such as tests, scans or a review of medical history.
Prior treatment: Treatment a person has already had for the condition. A 'line of therapy' is one course of treatment; studies often require, or limit, the number of prior lines.
MRI: A scan that uses magnets and radio waves, not X-rays, to make detailed pictures of the inside of the body. Some implants and metal objects mean a person cannot have one.
exclusion criteria: The conditions that rule a person out even if they meet the inclusion criteria, for example other illnesses, certain medicines or pregnancy.
open-label: No masking is used, so the assigned intervention is not deliberately hidden from participants or study staff.
ascending dose: Groups of participants receive increasing doses of a treatment, one group after another, to find a dose that can be given safely.
phase 1: An early-stage study, usually small, mainly to check safety, side effects and how much of a treatment can be given. Whether it works is not the main question yet.
pharmacokinetics: How the body absorbs, distributes, breaks down and removes a drug. It is studied by measuring drug levels or related substances at set times after a dose.
pharmacodynamics: What a drug does to the body, for example how it changes a blood marker or a symptom, and how that relates to the dose.
enrolment: The number of participants a study plans to include, or has included. 'Estimated' means the planned number; 'actual' means the number who joined.
Cohort: A group of people who share a characteristic, such as a diagnosis, and are studied together. 'Prospective' means they are followed forward from enrolment; 'retrospective' means existing records are reviewed.
observational: A study in which researchers do not assign participants to a treatment or other intervention. They observe or measure what happens, which may include study visits, tests, questionnaires or a review of medical records.

The study record on this page is reproduced from ClinicalTrials.gov, a database of the U.S. National Library of Medicine, where it was submitted by the study sponsor. MedicalUpdates.ai does not own this content, is not affiliated with or endorsed by ClinicalTrials.gov, NIH, or the U.S. Government, and does not verify the record. Plain-language notes, the glossary and the questions above are added by this site; text in the boxes marked "AI summary" was written by an AI model and may contain errors. Registry records change over time. Check the original record for the current version and discuss eligibility or participation with a qualified healthcare professional.

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