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Testing a new drug VO659 for genetic neurodegenerative diseases

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

Phase1; Phase2 Interventional Vico Therapeutics B. V. · NCT05822908

This study is testing a new drug called VO659 to see if it is safe and can help people with spinocerebellar ataxia types 1 and 3 or Huntington's disease.

Quick facts

PhasePhase1; Phase2
Study typeInterventional
Enrollment68 (estimated)
Ages25 Years to 60 Years
SexAll
SponsorVico Therapeutics B. V. Industry-sponsored
Locations14 sites (Copenhagen and 13 other locations)
Trial IDNCT05822908 on ClinicalTrials.gov

What this trial studies

This clinical trial aims to evaluate the safety and tolerability of the drug VO659 in patients with spinocerebellar ataxia types 1 and 3, as well as Huntington's disease. It is a first-in-human, open-label, multiple ascending dose trial that will assess the pharmacokinetics of the drug after intrathecal administration. Participants will be assigned to different dose cohorts based on their enrollment order, with a total trial duration of approximately 42 weeks. The study will focus on individuals with mild to moderate symptoms of these conditions, aiming to gather data on the drug's effects on disease progression.

Who should consider this trial

Good fit: Ideal candidates are adults aged 25 to 60 with genetically confirmed mild to moderate spinocerebellar ataxia types 1 or 3, or early-stage Huntington's disease.

Not a fit: Patients with advanced stages of these diseases or those outside the specified age range may not benefit from this study.

Why it matters

Potential benefit: If successful, this trial could lead to a new treatment option that may slow or halt the progression of debilitating neurodegenerative diseases.

How similar studies have performed: While this approach is novel in humans, preclinical data suggest potential efficacy, indicating a promising avenue for treatment.

Eligibility criteria

Show full inclusion / exclusion 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:

  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

Where this trial is running

Copenhagen and 13 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
View on ClinicalTrials.gov → Find more trials like this →
Conditions Spinocerebellar Ataxia Type 1Spinocerebellar Ataxia Type 3Huntington Diseasehereditary ataxiaMachado-Joseph Disease
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.