Huntington's DiseasePhase 3NCT05655520
A Study to Evaluate the Safety and Tolerability of SAGE-718 in Participants With Huntington's Disease
A Phase 3 study testing SAGE-718 in people with Huntington's Disease, run by Supernus Pharmaceuticals, Inc. at 43 sites in 4 countries.
Trial summary
The primary purpose of the study is to evaluate the safety and tolerability of SAGE-718 softgel lipid capsule in participants with Huntington's Disease (HD) Read more about this study
- Who is it for?
- Ages 25 to 65 years
- Conditions the study is for
- Huntington's Disease
- What is being tested?
- SAGE-718
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 153 participants
- Where
- 43 sitesin 4 countries
- Study dates
- 14 Dec 2022to 20 Jan 2025
- Phase
- Phase 3
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 25 to 65 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- For all participants:
- Completed 718-CIH-201 (NCT05107128) or 718-CIH-202 (NCT05358821) studies or meet eligibility criteria for the de novo cohort.
- Agree to refrain from drugs of abuse for the duration of the study and from alcohol during the 48 hours preceding each study visit.
- Be willing to invite a study partner, if available, who is reliable, competent, and at least 18 years of age to participate in the study.
- Be able to travel to the study center, and, judged by the investigator, is likely to be able to continue to travel to the study center to complete study visits for the duration of the study.
- Additional inclusion criteria for the de novo cohort (Cohort 3):
Show all 11Show fewer
- Be at least 25 years old, but not older than 65 years of age at Screening.
- Genetically confirmed disease with cytosine-adenine-guanine (CAG) expansion ≥40
- No features of juvenile HD
- CAG-Age-Product (CAP) score ≥90, as calculated using the CAP formula: AGE × (CAG - 30) / 6.49.
- At screening, scores of either: a) Unified Huntington's Disease Rating Scale (UHDRS) -Total Functional Capacity (TFC)=13 and Montreal Cognitive Assessment (MoCA) ≤25 score, or b) UHDRS-TFC ≤12 and MoCA >25
Who cannot join
- For all participants
- Have a diagnosis of an ongoing neurodegenerative condition other than HD, including but not limited to, Alzheimer's Disease, vascular dementia, dementia with Lewy bodies, or Parkinson's Disease.
- Had gastric bypass surgery, has a gastric sleeve or lap band, or has had any related procedures that interfere with gastrointestinal transit.
- Is known to be allergic to any of SAGE-718 excipients, including soy lecithin.
- Receive any prohibited medications within 30 days of screening and during participation in the study.
- Additional exclusion criteria for the de novo cohort (Cohort 3):
Show all 11Show fewer
- Have previous exposure to gene therapy, or have participated in any other HD investigational drug, biologic, or device trial within 180 days or a non-HD drug, biologic or device trial within 30 days or 5 half-lives (whichever is longer). Additionally, participants who have received treatment with antisense oligonucleotides or a messenger ribonucleic acid (mRNA) splicing modifier will be excluded.
- Note: Participants with confirmation of enrolment in the placebo arm of these investigational trials would not be excluded.
- Additional exclusion criteria for 718-CIH-201/202 completers (Cohorts 1 and 2):
- Have one or more ongoing serious adverse events (SAEs) from the parent study.
- Have ongoing, unresolved AE(s), which in the opinion of the investigator or sponsor, is likely to interfere with study conduct or compliance.
Trial locations and contacts
43 sites in 4 countries.
43 sites in 4 countries
United States29 sites
Sage Investigational Site
Baltimore, Maryland, 21287
Sage Investigational Site
Birmingham, Alabama, 35233
Sage Investigational Site
Boca Raton, Florida, 33431
Sage Investigational Site
Boston, Massachusetts, 02215
Sage Investigational Site
Chapel Hill, North Carolina, 27599
Sage Investigational Site
Charleston, South Carolina, 29425
Sage Investigational Site
Chicago, Illinois, 60611
Sage Investigational Site
Chicago, Illinois, 60612
Sage Investigational Site
Cincinnati, Ohio, 45219
Sage Investigational Site
Durham, North Carolina, 27705
Sage Investigational Site
Englewood, Colorado, 80113
Sage Investigational Site
Houston, Texas, 77030
Sage Investigational Site
Indianapolis, Indiana, 46202
Sage Investigational Site
Iowa City, Iowa, 52242
Sage Investigational Site
Kansas City, Kansas, 66103
Sage Investigational Site
La Jolla, California, 92037
Sage Investigational Site
Little Rock, Arkansas, 72205
Sage Investigational Site
Los Alamitos, California, 90720
Sage Investigational Site
Los Angeles, California, 90095
Sage Investigational Site
Memphis, Tennessee, 38157
Sage Investigational Site
New York, New York, 10032
Sage Investigational Site
Philadelphia, Pennsylvania, 19107
Sage Investigational Site
Richmond, Virginia, 23298
Sage Investigational Site
Sacramento, California, 95817
Sage Investigational Site
Spokane, Washington, 99202
Sage Investigational Site
Tampa, Florida, 33612
Sage Investigational Site
Toledo, Ohio, 43614
Sage Investigational Site
Washington D.C., District of Columbia, 20007
Sage Investigational Site
Williamsville, New York, 14221
United Kingdom8 sites
Sage Investigational Site
Aberdeen, Scotland, AB25 2ZA
Sage Investigational Site
Birmingham, West Midlands, B15 2FG
Sage Investigational Site
Cardiff, Wales, CF144XW
Sage Investigational Site
Leeds, West Yorkshire, LS7 4SA
Sage Investigational Site
Newcastle, Upon Tyne, NE6 4QD
Sage Investigational Site
Plymouth, Derriford, PL6 8BT
Sage Investigational Site
Southampton, England, SO16 6YD
Sage Investigational Site
Tooting, London, SW17 0QT
Australia3 sites
Sage Investigational Site
Caulfield South, Victoria, 3162
Sage Investigational Site
Nedlands, Western Australia, 6009
Sage Investigational Site
Westmead, New South Wales, 2145
Canada3 sites
Sage Investigational Site
Halifax, Nova Scotia, B3S1N2
Sage Investigational Site
Montreal, Quebec, H2X1R9
Sage Investigational Site
Toronto, Ontario, M2K 1E1
About this study
Official title: A Phase 3, Multicenter, Open-label Safety Study to Evaluate the Long-term Safety and Tolerability of SAGE-718 in Participants With Huntington's Disease
The primary purpose of the study is to evaluate the safety and tolerability of SAGE-718 softgel lipid capsule in participants with Huntington's Disease (HD)
- Conditions
- Huntington's Disease
- Being tested
- SAGE-718
- Keywords
- Huntington's Disease, SAGE-718
- Medical subject headings
- Huntington Disease
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
SAGE-718Drug
Oral softgel lipid capsules
| Study group | Role | What they receive |
|---|---|---|
| Cohort 1 (Direct Rollover) | Experimental | Participants from the studies 718-CIH-201 (NCT05107128) and 718-CIH-202 (NCT05358821) who will sign the informed consent for study 718-CIH-301 ≤7 days after the last day of the corresponding parent study will be enrolled in this cohort. Participants will receive Sage-718, 0.9 milligrams (mg), orally once daily from Day 1 onwards. Receives: Drug: SAGE-718 |
| Cohort 2 (Gap Rollover) | Experimental | Participants from the studies 718-CIH-201 (NCT05107128) and 718-CIH-202 (NCT05358821) who will sign the informed consent for study 718-CIH-301 after a gap of >7 days after the last day of the corresponding parent study will be enrolled in this cohort. Participants will receive Sage-718 0.9 mg, orally once daily from Day 1 onwards. Receives: Drug: SAGE-718 |
| Cohort 3 (De Novo) | Experimental | Participants who were not previously included in any SAGE-718 clinical study. Participants will receive Sage-718 from Day 1 onwards. Receives: Drug: SAGE-718 |
What is being measured
The primary outcome is the main question the study is designed to answer.
Number of Participants With at Least One Treatment-Emergent Adverse Events (TEAEs)
An Adverse Event (AE) is any untoward medical occurrence in a patient or clinical investigation participant administered a pharmaceutical product and that does not necessarily have a causal relationship with this treatment. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom or disease temporally associated with the use of a medicinal (investigational) product whether or not related to the medicinal (investigational) product. A TEAE is defined as an AE with onset after the start of IP, or any worsening of a pre-existing medical condition/AE with onset after the start of IP and throughout the study.
Measured: Up to 24 months
Number of Participants With at Least One TEAE by Severity
A TEAE is defined as an AE with onset after the start of IP, or any worsening of a pre-existing medical condition/AE with onset after the start of IP and throughout the study. Severity was assessed as:
Mild: symptoms barely noticeable to participant or does not make participant uncomfortable; does not influence performance or functioning; prescription drug not ordinarily needed for relief of symptoms.
Moderate: symptoms of a sufficient severity to make participant uncomfortable; performance of daily activity is influenced; participant is able to continue in study; treatment for symptoms may be needed.
Severe: symptoms cause severe discomfort; symptoms cause incapacitation or significant impact on participant's daily life; severity may cause cessation of treatment with IP; treatment for symptoms may be given and/or participant hospitalized.
Participant with multiple instances of events is counted only once using maximum intensity.
Measured: Up to 24 months
Number of Participants Who Withdrew From Study Due to TEAEs
An AE is any untoward medical occurrence in a participant or clinical investigation participant administered a pharmaceutical product and that does not necessarily have a causal relationship with this treatment. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom or disease temporally associated with the use of a medicinal (investigational) product whether or not related to the medicinal (investigational) product. A TEAE is defined as any AE with onset or after the start of IP or any worsening of a pre-existing medical condition/AE with onset after the start of IP and throughout the study.
Measured: Up to 24 months
Change From Baseline in Vital Signs: Blood Pressure
Vital signs parameter for blood pressure included systolic blood pressure (supine), systolic blood pressure (standing 1 minute), systolic blood pressure (standing 3 minutes), diastolic blood pressure (supine), diastolic blood pressure (standing 1 minute), and diastolic blood pressure (standing 3 minutes).
Last value on study is defined as the last post-baseline value on or after the first dose of IP and on or before the last date of the study.
Measured: Baseline; Last Value on Study (up to 24 months)
Change From Baseline in Vital Signs: Heart Rate
Vital signs for heart rate included heart rate (supine), heart rate (standing 1 minute), and heart rate (standing 3 minute).
Last value on study is defined as the last post-baseline value on or after the first dose of IP and on or before the last date of the study.
Measured: Baseline, Last value on study (up to 24 months)
Change From Baseline in Vital Signs: Respiratory Rate
Last value on study is defined as the last post-baseline value on or after the first dose of IP and on or before the last date of the study.
Measured: Baseline; Last value on study (up to 24 months)
Change From Baseline in Vital Signs: Temperature
Last value on study is defined as the last post-baseline value on or after the first dose of IP and on or before the last date of the study.
Measured: Baseline, Last value on study (up to 24 months)
Change From Baseline in Clinical Laboratory Parameters: Hematology - Basophils, Eosinophils, Erythrocytes, Leukocytes, Lymphocytes, Monocytes, Neutrophils, Platelets
Last value on study is defined as the last post-baseline value on or after the first dose of IP and on or before the last date of the study.
Measured: Baseline; Last value on study (up to 24 months)
Change From Baseline in Clinical Laboratory Parameters: Hematology- Basophils/Leukocytes, Eosinophils/Leukocytes, Lymphocytes/Leukocytes, Monocytes/Leukocytes, Neutrophils/Leukocytes
Last value on study is defined as the last post-baseline value on or after the first dose of IP and on or before the last date of the study.
Measured: Baseline, Last value on study (up to 24 months)
Change From Baseline in Clinical Laboratory Parameters: Hematology- Erythrocytes (Ery.) Mean Corpuscular Hemoglobin (HGB) Concentration, Hemoglobin
Last value on study is defined as the last post-baseline value on or after the first dose of IP and on or before the last date of the study.
Measured: Baseline, Last value on study (up to 24 months)
Change From Baseline in Clinical Laboratory Parameters: Hematology - Erythrocytes Mean Corpuscular Hemoglobin
Last value on study is defined as the last post-baseline value on or after the first dose of IP and on or before the last date of the study.
Measured: Baseline; Last value on study (up to 24 months)
Change From Baseline in Clinical Laboratory Parameters: Hematology - Erythrocytes Mean Corpuscular Volume
Last value on study is defined as the last post-baseline value on or after the first dose of IP and on or before the last date of the study.
Measured: Baseline, Last value on study (up to 24 months)
Change From Baseline in Clinical Laboratory Parameters: Hematology - Hematocrit
Last value on study is defined as the last post-baseline value on or after the first dose of IP and on or before the last date of the study.
Measured: Baseline, Last value on study (up to 24 months)
Change From Baseline in Clinical Laboratory Parameters: Biochemistry- Alanine Aminotransferase, Alkaline Phosphatase, Aspartate Aminotransferase, Creatine Kinase, Gamma Glutamyl Transferase, Lactate Dehydrogenase
Last value on study is defined as the last post-baseline value on or after the first dose of IP and on or before the last date of the study.
Measured: Baseline, Last value on study (up to 24 months)
Change From Baseline in Clinical Laboratory Parameters: Biochemistry - Bicarbonate, Calcium, Chloride, Cholesterol, Glucose, HDL Cholesterol, LDL Cholesterol, Phosphate, Potassium, Sodium, Triglycerides, Urea Nitrogen
HDL= high-density lipoprotein LDL= low-density lipoprotein
Last value on study is defined as the last post-baseline value on or after the first dose of IP and on or before the last date of the study.
Measured: Baseline; Last value on study (up to 24 months)
Change From Baseline in Clinical Laboratory Parameters: Biochemistry - Albumin and Protein
Last value on study is defined as the last post-baseline value on or after the first dose of IP and on or before the last date of the study.
Measured: Baseline; Last value on study (up to 24 months)
Change From Baseline in Clinical Laboratory Parameters: Biochemistry - Bilirubin, Creatinine, Direct Bilirubin, Indirect Bilirubin
Last value on study is defined as the last post-baseline value on or after the first dose of IP and on or before the last date of the study.
Measured: Baseline; Last value on study (up to 24 months)
Change From Baseline in Clinical Laboratory Parameters: Biochemistry - Thyrotropin
Last value on study is defined as the last post-baseline value on or after the first dose of IP and on or before the last date of the study.
Measured: Baseline; Last value on study (up to 24 months)
Change From Baseline in Clinical Laboratory Parameters: Biochemistry - Thyroxine Free, Triiodothyronine Free
Last value on study is defined as the last post-baseline value on or after the first dose of IP and on or before the last date of the study.
Measured: Baseline; Last value on study (up to 24 months)
Change From Baseline in Clinical Laboratory Parameters: Urinalysis- Erythrocytes in Urine, Leukocytes in Urine, Renal Epithelial Casts, Squamous Epithelial Cells, Transitional Epithelial Cells
Last value on study is defined as the last post-baseline value on or after the first dose of IP and on or before the last date of the study.
Measured: Baseline; Last value on study (up to 24 months)
Change From Baseline in Clinical Laboratory Parameters: Urinalysis- Hyaline Casts
Last value on study is defined as the last post-baseline value on or after the first dose of IP and on or before the last date of the study.
Measured: Baseline; Last value on study (up to 24 months)
Change From Baseline in Clinical Laboratory Parameters: Urinalysis- pH
Last value on study is defined as the last post-baseline value on or after the first dose of IP and on or before the last date of the study.
Measured: Baseline; Last value on study (up to 24 months)
Change From Baseline in Clinical Laboratory Parameters: Coagulation- Activated Partial Thromboplastin Time, Prothrombin Time
Last value on study is defined as the last post-baseline value on or after the first dose of IP and on or before the last date of the study.
Measured: Baseline; Last value on study (up to 24 months)
Change From Baseline in Clinical Laboratory Parameters: Coagulation- Prothrombin International (Intl) Normalized Ratio
Last value on study is defined as the last post-baseline value on or after the first dose of IP and on or before the last date of the study.
Measured: Baseline; Last value on study (up to 24 months)
Change From Baseline in Electrocardiograms (ECGs) Parameters: Mean Heart Rate
Last value on study is defined as the last post-baseline value on or after the first dose of IP and on or before the last date of the study.
Measured: Baseline; Last value on study (up to 24 months)
Change From Baseline in ECG Parameters - PR Interval Aggregate, QRS Duration Aggregate, QT Interval Aggregate and QTcF Interval Aggregate
Last value on study is defined as the last post-baseline value on or after the first dose of IP and on or before the last date of the study.
Measured: Baseline; Last value on study (up to 24 months)
Number of Participants With Change From Baseline in Columbia Suicide Severity Rating Scale (C-SSRS) Responses
Columbia Suicide Severity Rating Scale evaluates and assesses the lifetime experience of participants with suicidal ideation (SI) and suicidal behavior (SB) and post-baseline evaluation that focuses on suicidality since last study visit. C-SSRS includes "yes" or "no"' responses for assessment of SI and SB as well as numeric ratings for severity of ideation. If present [from 1 (minor physical damage) to 5 (death), with 5 being most severe]. If any of the available assessments in suicidal behavior is Yes, the category is considered as 'Suicidal behavior'. If any of these available assessments in suicidal ideation is Yes but all available assessments in suicidal behavior is NO, the category is considered as 'Suicidal Ideation'. Data is reported for only those timepoints where there was a change in assessment (response) from Baseline. Baseline is the worst of assessments done in any question in SI/SB prior to first dose of IP, excluding lifetime assessment.
Measured: Day 30, Day 60, Day 90, Day 365, Day 395, Safety Follow-up (up to 24 months)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted19 Dec 2022
- Study start14 Dec 2022
- Primary completion20 Jan 2025
- Study completion20 Jan 2025
Why it stopped: Internal company decision
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Other trials for Huntington's DiseaseStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 3
- Primary purpose
- Treatment
- Allocation
- Non-randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 153 participants (actual)
Sponsor and investigators
- Lead sponsor
- Supernus Pharmaceuticals, Inc.
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05655520
- Sponsor's protocol ID
- 718-CIH-301
- Status last verified
- Aug 2025
- First submitted
- 9 Dec 2022
- Last updated
- 17 Dec 2025
- Results posted
- Yes, on ClinicalTrials.gov
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No: Data sharing will be consistent with the results submission policy of ClinicalTrials.gov
Study at a glance
From the registry record, last updated by the sponsor on 17 Dec 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Phase 3, Multicenter, Open-label Safety Study to Evaluate the Long-term Safety and Tolerability of SAGE-718 in Participants With Huntington's Disease
- ClinicalTrials.gov ID
- NCT05655520
- Acronym / sponsor ID
- 718-CIH-301
- Conditions
- Huntington's Disease
- Keywords
- Huntington's Disease, SAGE-718
- Phase
- Phase 3
- Study type
- Interventional
- Recruitment status
- TerminatedReason stopped: Internal company decision
- Enrolment
- 153 participants (actual)
- Lead sponsor
- Supernus Pharmaceuticals, Inc.Industry (pharma, biotech, devices)
- Study start
- 14 Dec 2022 (actual)
- Primary completion
- 20 Jan 2025 (actual)
- Study completion
- 20 Jan 2025 (actual)
- First posted
- 19 Dec 2022 (actual)
- Results
- Posted 17 Dec 2025
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The primary purpose of the study is to evaluate the safety and tolerability of SAGE-718 softgel lipid capsule in participants with Huntington's Disease (HD)
Study design
- Primary purpose
- Treatment
- Allocation
- Non-randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| Cohort 1 (Direct Rollover) | Experimental | Drug: SAGE-718Participants from the studies 718-CIH-201 (NCT05107128) and 718-CIH-202 (NCT05358821) who will sign the informed consent for study 718-CIH-301 ≤7 days after the last day of the corresponding parent study will be enrolled in this cohort. Participants will receive Sage-718, 0.9 milligrams (mg), orally once daily from Day 1 onwards. |
| Cohort 2 (Gap Rollover) | Experimental | Drug: SAGE-718Participants from the studies 718-CIH-201 (NCT05107128) and 718-CIH-202 (NCT05358821) who will sign the informed consent for study 718-CIH-301 after a gap of >7 days after the last day of the corresponding parent study will be enrolled in this cohort. Participants will receive Sage-718 0.9 mg, orally once daily from Day 1 onwards. |
| Cohort 3 (De Novo) | Experimental | Drug: SAGE-718Participants who were not previously included in any SAGE-718 clinical study. Participants will receive Sage-718 from Day 1 onwards. |
Who may qualify
- Ages
- 25 to 65 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (11 listed)
- Completed 718-CIH-201 (NCT05107128) or 718-CIH-202 (NCT05358821) studies or meet eligibility criteria for the de novo cohort.
- Agree to refrain from drugs of abuse for the duration of the study and from alcohol during the 48 hours preceding each study visit.
- Be willing to invite a study partner, if available, who is reliable, competent, and at least 18 years of age to participate in the study.
- Be able to travel to the study center, and, judged by the investigator, is likely to be able to continue to travel to the study center to complete study visits for the duration of the study.
- Be at least 25 years old, but not older than 65 years of age at Screening.
Key exclusion criteria (11 listed)
- For all participants
- Have a diagnosis of an ongoing neurodegenerative condition other than HD, including but not limited to, Alzheimer's Disease, vascular dementia, dementia with Lewy bodies, or Parkinson's Disease.
- Had gastric bypass surgery, has a gastric sleeve or lap band, or has had any related procedures that interfere with gastrointestinal transit.
- Is known to be allergic to any of SAGE-718 excipients, including soy lecithin.
- Receive any prohibited medications within 30 days of screening and during participation in the study.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| SAGE-718Oral softgel lipid capsules | Drug | Cohort 1 (Direct Rollover), Cohort 2 (Gap Rollover), Cohort 3 (De Novo) |
Primary outcome
Number of Participants With at Least One Treatment-Emergent Adverse Events (TEAEs)
Time frame: Up to 24 months
An Adverse Event (AE) is any untoward medical occurrence in a patient or clinical investigation participant administered a pharmaceutical product and that does not necessarily have a causal relationship with this treatment. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom or disease temporally associated with the use of a medicinal (investigational) product whether or not related to the medicinal (investigational) product. A TEAE is defined as an AE with onset after the start of IP, or any worsening of a pre-existing medical condition/AE with onset after the start of IP and throughout the study.
Number of Participants With at Least One TEAE by Severity
Time frame: Up to 24 months
A TEAE is defined as an AE with onset after the start of IP, or any worsening of a pre-existing medical condition/AE with onset after the start of IP and throughout the study. Severity was assessed as: Mild: symptoms barely noticeable to participant or does not make participant uncomfortable; does not influence performance or functioning; prescription drug not ordinarily needed for relief of symptoms. Moderate: symptoms of a sufficient severity to make participant uncomfortable; performance of daily activity is influenced; participant is able to continue in study; treatment for symptoms may be needed. Severe: symptoms cause severe discomfort; symptoms cause incapacitation or significant impact on participant's daily life; severity may cause cessation of treatment with IP; treatment for symptoms may be given and/or participant hospitalized. Participant with multiple instances of events is counted only once using maximum intensity.
Number of Participants Who Withdrew From Study Due to TEAEs
Time frame: Up to 24 months
An AE is any untoward medical occurrence in a participant or clinical investigation participant administered a pharmaceutical product and that does not necessarily have a causal relationship with this treatment. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom or disease temporally associated with the use of a medicinal (investigational) product whether or not related to the medicinal (investigational) product. A TEAE is defined as any AE with onset or after the start of IP or any worsening of a pre-existing medical condition/AE with onset after the start of IP and throughout the study.
Change From Baseline in Vital Signs: Blood Pressure
Time frame: Baseline; Last Value on Study (up to 24 months)
Vital signs parameter for blood pressure included systolic blood pressure (supine), systolic blood pressure (standing 1 minute), systolic blood pressure (standing 3 minutes), diastolic blood pressure (supine), diastolic blood pressure (standing 1 minute), and diastolic blood pressure (standing 3 minutes). Last value on study is defined as the last post-baseline value on or after the first dose of IP and on or before the last date of the study.
Change From Baseline in Vital Signs: Heart Rate
Time frame: Baseline, Last value on study (up to 24 months)
Vital signs for heart rate included heart rate (supine), heart rate (standing 1 minute), and heart rate (standing 3 minute). Last value on study is defined as the last post-baseline value on or after the first dose of IP and on or before the last date of the study.
Change From Baseline in Vital Signs: Respiratory Rate
Time frame: Baseline; Last value on study (up to 24 months)
Last value on study is defined as the last post-baseline value on or after the first dose of IP and on or before the last date of the study.
Change From Baseline in Vital Signs: Temperature
Time frame: Baseline, Last value on study (up to 24 months)
Last value on study is defined as the last post-baseline value on or after the first dose of IP and on or before the last date of the study.
Change From Baseline in Clinical Laboratory Parameters: Hematology - Basophils, Eosinophils, Erythrocytes, Leukocytes, Lymphocytes, Monocytes, Neutrophils, Platelets
Time frame: Baseline; Last value on study (up to 24 months)
Last value on study is defined as the last post-baseline value on or after the first dose of IP and on or before the last date of the study.
Change From Baseline in Clinical Laboratory Parameters: Hematology- Basophils/Leukocytes, Eosinophils/Leukocytes, Lymphocytes/Leukocytes, Monocytes/Leukocytes, Neutrophils/Leukocytes
Time frame: Baseline, Last value on study (up to 24 months)
Last value on study is defined as the last post-baseline value on or after the first dose of IP and on or before the last date of the study.
Change From Baseline in Clinical Laboratory Parameters: Hematology- Erythrocytes (Ery.) Mean Corpuscular Hemoglobin (HGB) Concentration, Hemoglobin
Time frame: Baseline, Last value on study (up to 24 months)
Last value on study is defined as the last post-baseline value on or after the first dose of IP and on or before the last date of the study.
Change From Baseline in Clinical Laboratory Parameters: Hematology - Erythrocytes Mean Corpuscular Hemoglobin
Time frame: Baseline; Last value on study (up to 24 months)
Last value on study is defined as the last post-baseline value on or after the first dose of IP and on or before the last date of the study.
Change From Baseline in Clinical Laboratory Parameters: Hematology - Erythrocytes Mean Corpuscular Volume
Time frame: Baseline, Last value on study (up to 24 months)
Last value on study is defined as the last post-baseline value on or after the first dose of IP and on or before the last date of the study.
Change From Baseline in Clinical Laboratory Parameters: Hematology - Hematocrit
Time frame: Baseline, Last value on study (up to 24 months)
Last value on study is defined as the last post-baseline value on or after the first dose of IP and on or before the last date of the study.
Change From Baseline in Clinical Laboratory Parameters: Biochemistry- Alanine Aminotransferase, Alkaline Phosphatase, Aspartate Aminotransferase, Creatine Kinase, Gamma Glutamyl Transferase, Lactate Dehydrogenase
Time frame: Baseline, Last value on study (up to 24 months)
Last value on study is defined as the last post-baseline value on or after the first dose of IP and on or before the last date of the study.
Change From Baseline in Clinical Laboratory Parameters: Biochemistry - Bicarbonate, Calcium, Chloride, Cholesterol, Glucose, HDL Cholesterol, LDL Cholesterol, Phosphate, Potassium, Sodium, Triglycerides, Urea Nitrogen
Time frame: Baseline; Last value on study (up to 24 months)
HDL= high-density lipoprotein LDL= low-density lipoprotein Last value on study is defined as the last post-baseline value on or after the first dose of IP and on or before the last date of the study.
Change From Baseline in Clinical Laboratory Parameters: Biochemistry - Albumin and Protein
Time frame: Baseline; Last value on study (up to 24 months)
Last value on study is defined as the last post-baseline value on or after the first dose of IP and on or before the last date of the study.
Change From Baseline in Clinical Laboratory Parameters: Biochemistry - Bilirubin, Creatinine, Direct Bilirubin, Indirect Bilirubin
Time frame: Baseline; Last value on study (up to 24 months)
Last value on study is defined as the last post-baseline value on or after the first dose of IP and on or before the last date of the study.
Change From Baseline in Clinical Laboratory Parameters: Biochemistry - Thyrotropin
Time frame: Baseline; Last value on study (up to 24 months)
Last value on study is defined as the last post-baseline value on or after the first dose of IP and on or before the last date of the study.
Change From Baseline in Clinical Laboratory Parameters: Biochemistry - Thyroxine Free, Triiodothyronine Free
Time frame: Baseline; Last value on study (up to 24 months)
Last value on study is defined as the last post-baseline value on or after the first dose of IP and on or before the last date of the study.
Change From Baseline in Clinical Laboratory Parameters: Urinalysis- Erythrocytes in Urine, Leukocytes in Urine, Renal Epithelial Casts, Squamous Epithelial Cells, Transitional Epithelial Cells
Time frame: Baseline; Last value on study (up to 24 months)
Last value on study is defined as the last post-baseline value on or after the first dose of IP and on or before the last date of the study.
Change From Baseline in Clinical Laboratory Parameters: Urinalysis- Hyaline Casts
Time frame: Baseline; Last value on study (up to 24 months)
Last value on study is defined as the last post-baseline value on or after the first dose of IP and on or before the last date of the study.
Change From Baseline in Clinical Laboratory Parameters: Urinalysis- pH
Time frame: Baseline; Last value on study (up to 24 months)
Last value on study is defined as the last post-baseline value on or after the first dose of IP and on or before the last date of the study.
Change From Baseline in Clinical Laboratory Parameters: Coagulation- Activated Partial Thromboplastin Time, Prothrombin Time
Time frame: Baseline; Last value on study (up to 24 months)
Last value on study is defined as the last post-baseline value on or after the first dose of IP and on or before the last date of the study.
Change From Baseline in Clinical Laboratory Parameters: Coagulation- Prothrombin International (Intl) Normalized Ratio
Time frame: Baseline; Last value on study (up to 24 months)
Last value on study is defined as the last post-baseline value on or after the first dose of IP and on or before the last date of the study.
Change From Baseline in Electrocardiograms (ECGs) Parameters: Mean Heart Rate
Time frame: Baseline; Last value on study (up to 24 months)
Last value on study is defined as the last post-baseline value on or after the first dose of IP and on or before the last date of the study.
Change From Baseline in ECG Parameters - PR Interval Aggregate, QRS Duration Aggregate, QT Interval Aggregate and QTcF Interval Aggregate
Time frame: Baseline; Last value on study (up to 24 months)
Last value on study is defined as the last post-baseline value on or after the first dose of IP and on or before the last date of the study.
Number of Participants With Change From Baseline in Columbia Suicide Severity Rating Scale (C-SSRS) Responses
Time frame: Day 30, Day 60, Day 90, Day 365, Day 395, Safety Follow-up (up to 24 months)
Columbia Suicide Severity Rating Scale evaluates and assesses the lifetime experience of participants with suicidal ideation (SI) and suicidal behavior (SB) and post-baseline evaluation that focuses on suicidality since last study visit. C-SSRS includes "yes" or "no"' responses for assessment of SI and SB as well as numeric ratings for severity of ideation. If present [from 1 (minor physical damage) to 5 (death), with 5 being most severe]. If any of the available assessments in suicidal behavior is Yes, the category is considered as 'Suicidal behavior'. If any of these available assessments in suicidal ideation is Yes but all available assessments in suicidal behavior is NO, the category is considered as 'Suicidal Ideation'. Data is reported for only those timepoints where there was a change in assessment (response) from Baseline. Baseline is the worst of assessments done in any question in SI/SB prior to first dose of IP, excluding lifetime assessment.
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 17 Dec 2025.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- Individual participant dataSharing planned: No. Data sharing will be consistent with the results submission policy of ClinicalTrials.gov
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
43 sites in 4 countries: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 3 study testing SAGE-718 in people with Huntington's Disease, run by Supernus Pharmaceuticals, Inc. at 43 sites in 4 countries.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 11 inclusion and 11 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: stopped early, as of the sponsor's last update on 17 Dec 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 43 sites in United States, United Kingdom, Australia, Canada. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
Yes. Results are posted in the registry (first posted 17 Dec 2025). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Number of Participants With at Least One Treatment-Emergent Adverse Events (TEAEs) (time frame: Up to 24 months). The study lists 27 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 17 Dec 2025.