Phase 3 Huntington's Disease Trial, Completed

Written by an AI model from the ClinicalTrials.gov eligibility criteria and checked on a sample basis. Please confirm against the original criteria.

Who might be able to join this trial:

• You are 18 years old or older (or the age of legal adulthood in your location, whichever is older)
• You have been diagnosed with Huntington's disease (HD) confirmed by a genetic test showing an expanded CAG repeat number of 37 or higher
• You either completed a specific previous study called "First-HD" (SD-809-C-15), OR you have been taking an FDA-approved dose of tetrabenazine (a medication for HD-related involuntary movements) at a stable dose for at least 8 weeks before the screening visit and it is helping to control your movements
• Your Total Functional Capacity (TFC) score — a measure of your ability to carry out daily activities — is 5 or above at screening (confirm with trial site)
• You are able to swallow the study medication whole
• You are able to walk at least 20 yards without someone physically helping you (walking aids such as a cane or walker are allowed)
• You have good enough reading ability to fill out patient questionnaires
• You have a reliable caregiver who sees you every day, can help manage your study medication, can bring you to study visits, and can take part in assessments
• You are willing and able to give written consent, or have a legal representative who can do so on your behalf
• You have completed a Research Advance Directive (a document about future research participation preferences — confirm with trial site)
• Female participants who could become pregnant agree to use an acceptable form of contraception from screening through the end of the study

Who may not be able to join:

• You have a serious psychiatric condition, such as depression, that is not being treated or not well-managed
• You are currently having thoughts of suicide at the time of screening or the baseline visit
• You have a history of suicidal behaviour
• You show signs of depression at the baseline visit
• You have an unstable or serious medical condition at screening or the baseline visit
• You have taken tetrabenazine within 7 days before the baseline visit (applies to participants rolling over from the previous study only)
• You have taken certain medications within 30 days before screening, including: antipsychotics, metoclopramide, MAO inhibitors, levodopa or dopamine-boosting drugs, reserpine, or amantadine — and for rollover participants, memantine (note: if you are a "switch" participant already on a stable approved dose of memantine for at least 30 days, this may not apply — confirm with trial site)
• You have significant difficulty swallowing at screening or the baseline visit
• You have significantly impaired speech at screening or the baseline visit
• You need to take medications known to affect heart rhythm in a specific way (prolong the QT interval — confirm with trial site)
• A heart test (ECG) at screening shows an abnormal heart rhythm pattern called a prolonged QT interval
• You have evidence of liver problems at screening
• You have evidence of significant kidney problems at screening
• You have a known allergy to any ingredient in the study medication
• You are currently pregnant or breastfeeding
• You are currently using illegal/illicit drugs
• You have had a problem with alcohol or substance misuse in the past 12 months
• You have taken part in another clinical drug or device trial (other than the First-HD study) within 30 days — or 5 times the drug's half-life, whichever is longer — before screening (confirm with trial site)

Important: Always verify eligibility with the trial site directly before applying.