Flag of the European Union EU Clinical Trials Register Help

Clinical trials

The European Union Clinical Trials Register   allows you to search for protocol and results information on:
  • interventional clinical trials that were approved in the European Union (EU)/European Economic Area (EEA) under the Clinical Trials Directive 2001/20/EC
  • clinical trials conducted outside the EU/EEA that are linked to European paediatric-medicine development

    • EU/EEA interventional clinical trials approved under or transitioned to the Clinical Trial Regulation 536/2014 are publicly accessible through the
    Clinical Trials Information System (CTIS).

    The EU Clinical Trials Register currently displays   44347   clinical trials with a EudraCT protocol, of which   7375   are clinical trials conducted with subjects less than 18 years old.   The register also displays information on   18700   older paediatric trials (in scope of Article 45 of the Paediatric Regulation (EC) No 1901/2006).

    Phase 1 trials conducted solely on adults and that are not part of an agreed paediatric investigation plan (PIP) are not publicly available (see Frequently Asked Questions ).  
     
    Examples: Cancer AND drug name. Pneumonia AND sponsor name.
    How to search [pdf]
    Search Tips: Under advanced search you can use filters for Country, Age Group, Gender, Trial Phase, Trial Status, Date Range, Rare Diseases and Orphan Designation. For these items you should use the filters and not add them to your search terms in the text field.
    Advanced Search: Search tools
     

    < Back to search results

    Download PDF

    Clinical Trial Results:
    Phase IIb, randomized, double-blind, placebo-controlled study in parallel groups assessing the efficacy and safety of two doses of SOM3355 in patients suffering from Huntington’s Disease with choreic movements.

    Summary
    EudraCT number
    		 2021-003453-28
    Trial protocol
    		 ES   FR   IT   DE  
    Global end of trial date
    25 Jun 2024

    Results information
    Results version number
    		 v1(current)
    This version publication date
    06 Jul 2025
    First version publication date
    06 Jul 2025
    Other versions

    Trial information

    		 Close Top of page
    Trial identification
    Sponsor protocol code
    SOMCT03
    Additional study identifiers
    ISRCTN number
    		 -
    US NCT number
    		 NCT05475483
    WHO universal trial number (UTN)
    		 -
    Sponsors
    Sponsor organisation name
    SOM Innovation Biotech SA
    Sponsor organisation address
    Baldiri Reixac, 4, Barcelona, Spain, 08028
    Public contact
    Clinical Trial Information Desk, SOM Innovation Biotech SA (SOM Biotech), +34 934 020 150, info@sombiotech.com
    Scientific contact
    Clinical Trial Information Desk, SOM Innovation Biotech SA (SOM Biotech), +34 934 020 150, info@sombiotech.com
    Paediatric regulatory details
    Is trial part of an agreed paediatric investigation plan (PIP)
    No
    Does article 45 of REGULATION (EC) No 1901/2006 apply to this trial?
    No
    Does article 46 of REGULATION (EC) No 1901/2006 apply to this trial?
    No
    Results analysis stage
    Analysis stage
    Final
    Date of interim/final analysis
    17 Jul 2024
    Is this the analysis of the primary completion data?
    Yes
    Primary completion date
    25 Jun 2024
    Global end of trial reached?
    Yes
    Global end of trial date
    25 Jun 2024
    Was the trial ended prematurely?
    No
    General information about the trial
    Main objective of the trial
    The primary objective of the study is to assess the efficacy of two doses of SOM3355 (400 mg/day and 600 mg/day taken twice daily [BID] over at least 8 weeks at maintenance dose) compared to placebo to reduce chorea in HD patients measured by the change in TMC score (primary efficacy endpoint).
    Protection of trial subjects
    This study was conducted following the protocol and according to the ethical principles derived from the International Council for Harmonisation (ICH) guidelines for Good Clinical Practice (GCP), and applicable laws and regulations.
    Background therapy
    		 -
    Evidence for comparator
    		 -
    Actual start date of recruitment
    02 Aug 2022
    Long term follow-up planned
    No
    Independent data monitoring committee (IDMC) involvement?
    Yes
    Population of trial subjects
    Number of subjects enrolled per country
    Country: Number of subjects enrolled
    Poland: 26
    Country: Number of subjects enrolled
    Spain: 35
    Country: Number of subjects enrolled
    France: 15
    Country: Number of subjects enrolled
    Germany: 21
    Country: Number of subjects enrolled
    Italy: 19
    Country: Number of subjects enrolled
    United Kingdom: 18
    Country: Number of subjects enrolled
    Switzerland: 5
    Worldwide total number of subjects
    139
    EEA total number of subjects
    116
    Number of subjects enrolled per age group
    In utero
    0
    Preterm newborn - gestational age < 37 wk
    0
    Newborns (0-27 days)
    0
    Infants and toddlers (28 days-23 months)
    0
    Children (2-11 years)
    0
    Adolescents (12-17 years)
    0
    Adults (18-64 years)
    120
    From 65 to 84 years
    19
    85 years and over
    0

    Subject disposition

    		 Close Top of page
    Recruitment
    Recruitment details
    		 A total of 139 patients with Huntington's disease were randomized and treated between August 2022 and April 2024 at 23 sites in 7 European countries.

    Pre-assignment
    Screening details
    		 The main inclusion criteria were having a Unified Huntington's Disease Rating Scale (UHDRS) Total Maximal Chorea (TMC) score ≥10 and Total Functional Capacity (TFC) score ≥7. The main exclusion criteria were being co-administered with VMAT2 inhibitors or other antichoreic treatments, having hypotension, or taking >2 antihypertensive drugs.

    Period 1
    Period 1 title
    Overall trial (overall period)
    Is this the baseline period?
    		 Yes
    Allocation method
    Randomised - controlled
    Blinding used
    		 Double blind
    Roles blinded
    		 Investigator, Subject, Monitor, Data analyst, Carer, Assessor
    Blinding implementation details
    All participants, site staff, Sponsor, contract research organization (CRO), and vendors involved with the study remained blinded to treatment assignments until the database was locked and the study unblinded.

    Arms
    Are arms mutually exclusive
    Yes

    Arm title
    		 Placebo
    Arm description
    		 -
    Arm type
    		 Placebo

    Investigational medicinal product name
    Placebo
    Investigational medicinal product code
    Other name
    Pharmaceutical forms
    Capsule, hard
    Routes of administration
    Oral use
    Dosage and administration details
    Placebo capsules were administered once daily (OD) for up-titration and down-titration (1 week each) and twice daily (BID) for at least 9 weeks at maintenance dose.

    Arm title
    		 SOM3355 400mg/day
    Arm description
    		 -
    Arm type
    		 Experimental

    Investigational medicinal product name
    SOM3355 400mg/day
    Investigational medicinal product code
    Other name
    Pharmaceutical forms
    Capsule, hard
    Routes of administration
    Oral use
    Dosage and administration details
    SOM3355 200mg capsules were administered once daily (OD) for up-titration and down-titration (1 week each) and twice daily (BID) for at least 9 weeks at maintenance dose.

    Arm title
    		 SOM3355 600mg/day
    Arm description
    		 -
    Arm type
    		 Experimental

    Investigational medicinal product name
    SOM3355 600mg/day
    Investigational medicinal product code
    Other name
    Pharmaceutical forms
    Capsule, hard
    Routes of administration
    Oral use
    Dosage and administration details
    SOM3355 200mg capsules were administered once daily (OD) for up-titration and down-titration, and twice daily (BID) for up-titration (1 week each). SOM3355 300mg capsules were administered twice daily (BID) for at least 8 weeks at maintenance dose.

    Number of subjects in period 1
    		Placebo SOM3355 400mg/day SOM3355 600mg/day
    Started
    48
    41
    50
    Completed
    41
    36
    41
    Not completed
    7
    5
    9
         Subject was not available for a visit
    -
    1
    -
         Consent withdrawn by subject
    1
    3
    -
         Adverse event, non-fatal
    3
    1
    6
         Lost to follow-up
    1
    -
    -
         Protocol deviation
    2
    -
    3

    Baseline characteristics

    		 Close Top of page
    Baseline characteristics reporting groups
    Reporting group title
    Placebo
    Reporting group description
    		 -

    Reporting group title
    SOM3355 400mg/day
    Reporting group description
    		 -

    Reporting group title
    SOM3355 600mg/day
    Reporting group description
    		 -

    Reporting group values
    		 Placebo SOM3355 400mg/day SOM3355 600mg/day Total
    Number of subjects
    		 48 41 50 139
    Age categorical
    Units: Subjects
        In utero
    		 0 0 0 0
        Preterm newborn infants (gestational age < 37 wks)
    		 0 0 0 0
        Newborns (0-27 days)
    		 0 0 0 0
        Infants and toddlers (28 days-23 months)
    		 0 0 0 0
        Children (2-11 years)
    		 0 0 0 0
        Adolescents (12-17 years)
    		 0 0 0 0
        Adults (18-64 years)
    		 43 32 45 120
        From 65-84 years
    		 5 9 5 19
        85 years and over
    		 0 0 0 0
    Age continuous
    Units: years
        arithmetic mean (standard deviation)
    		 51.65 ( 10.46 ) 52.51 ( 12.39 ) 51.34 ( 12.12 ) -
    Gender categorical
    Units: Subjects
        Female
    		 28 17 21 66
        Male
    		 20 24 29 73
    Use of Neuroleptics
    Antipsychotic drugs (excluding haloperidol, pimozide, and tiapride) prescribed to treat behaviour disorders at a stable dose for at least 3 months before entering the study.
    Units: Subjects
        Yes
    		 6 5 6 17
        No
    		 42 36 44 122
    TMC score
    Baseline Total Maximal Chorea
    Units: unit(s)
        arithmetic mean (standard deviation)
    		 12.80 ( 2.58 ) 12.74 ( 2.93 ) 13.23 ( 2.84 ) -
    Subject analysis sets

    Subject analysis set title
    mITT
    Subject analysis set type
    		 Modified intention-to-treat
    Subject analysis set description
    Modified Intention-to-Treat (mITT) population included all patients randomized to a treatment arm, who received at least one dose of study drug and had at least one post-baseline assessment of the TMC score.

    Subject analysis set title
    SAF
    Subject analysis set type
    		 Safety analysis
    Subject analysis set description
    Safety (SAF) population included all patients who were administered at least one dose of any study drug (SOM3355 or placebo).

    Subject analysis sets values
    		 mITT SAF
    Number of subjects
    139
    139
    Age categorical
    Units: Subjects
        In utero
    0
    0
        Preterm newborn infants (gestational age < 37 wks)
    0
    0
        Newborns (0-27 days)
    0
    0
        Infants and toddlers (28 days-23 months)
    0
    0
        Children (2-11 years)
    0
    0
        Adolescents (12-17 years)
    0
    0
        Adults (18-64 years)
    120
    120
        From 65-84 years
    19
    19
        85 years and over
    0
    0
    Age continuous
    Units: years
        arithmetic mean (standard deviation)
    51.79 ( 11.58 )
    51.79 ( 11.58 )
    Gender categorical
    Units: Subjects
        Female
    66
    66
        Male
    73
    73
    Use of Neuroleptics
    Antipsychotic drugs (excluding haloperidol, pimozide, and tiapride) prescribed to treat behaviour disorders at a stable dose for at least 3 months before entering the study.
    Units: Subjects
        Yes
    17
    17
        No
    122
    122
    TMC score
    Baseline Total Maximal Chorea
    Units: unit(s)
        arithmetic mean (standard deviation)
    12.94 ( 2.77 )
    12.94 ( 2.77 )

    End points

    		 Close Top of page
    End points reporting groups
    Reporting group title
    Placebo
    Reporting group description
    		 -

    Reporting group title
    SOM3355 400mg/day
    Reporting group description
    		 -

    Reporting group title
    SOM3355 600mg/day
    Reporting group description
    		 -

    Subject analysis set title
    mITT
    Subject analysis set type
    		 Modified intention-to-treat
    Subject analysis set description
    Modified Intention-to-Treat (mITT) population included all patients randomized to a treatment arm, who received at least one dose of study drug and had at least one post-baseline assessment of the TMC score.

    Subject analysis set title
    SAF
    Subject analysis set type
    		 Safety analysis
    Subject analysis set description
    Safety (SAF) population included all patients who were administered at least one dose of any study drug (SOM3355 or placebo).

    Primary: Change in Total Maximal Chorea (TMC) score from baseline to end of maintenance dose (mITT - N=139)

    		 Close Top of page
    End point title
    		 Change in Total Maximal Chorea (TMC) score from baseline to end of maintenance dose (mITT - N=139)
    End point description
    The primary endpoint was the change in Total Maximal Chorea (TMC) score from baseline (defined for each patient as the average of values at the screening visit (Visit 0) and the inclusion visit (Visit 1)) to the end of maintenance dose (defined for each patient as the average of values at the end of Week 9 (Visit 4) and the end of Week 10 (Visit 5)). The primary efficacy analysis was conducted on the mITT Population, including 139 subjects.
    End point type
    Primary
    End point timeframe
    From baseline to end of maintenance dose (10 weeks of treatment).
    End point values
    		 Placebo SOM3355 400mg/day SOM3355 600mg/day
    Number of subjects analysed
    48
    41
    50
    Units: Change from baseline
        least squares mean (confidence interval 95%)
    -2.09 (-2.89 to -1.28)
    -2.31 (-3.15 to -1.47)
    -3.05 (-3.86 to -2.25)
    Statistical analysis title
    		 Mixed model for repeated measures (MMRM)
    Comparison groups
    Placebo v SOM3355 600mg/day
    Number of subjects included in analysis
    98
    Analysis specification
    Pre-specified
    Analysis type
    		 other
    P-value
    		 = 0.096
    Method
    		 Mixed models analysis
    Parameter type
    		 Mean difference (final values)
    Point estimate
    -0.97
    Confidence interval
         level
    		 95%
         sides
    2-sided
         lower limit
    		 -2.27
         upper limit
    		 0.34

    Secondary: Change in Clinical Global Impression (CGI) from baseline to end of maintenance dose (mITT - N=139)

    		 Close Top of page
    End point title
    		 Change in Clinical Global Impression (CGI) from baseline to end of maintenance dose (mITT - N=139)
    End point description
    The key secondary endpoint was the Clinical Global Impression of Change (CGI-C) at Visit 5 (week 10). The key secondary efficacy analysis was conducted on the mITT Population, including 139 subjects. Patients with a score of 1 (very much improved), 2 (much improved), or 3 (minimally improved) were defined as "Improved".
    End point type
    Secondary
    End point timeframe
    From baseline to end of maintenance dose (10 weeks of treatment).
    End point values
    		 Placebo SOM3355 400mg/day SOM3355 600mg/day
    Number of subjects analysed
    41
    37
    41
    Units: Subjects
        Improved
    15
    26
    23
        Not Improved
    26
    11
    18
    Statistical analysis title
    		 Logistic regression
    Comparison groups
    Placebo v SOM3355 600mg/day
    Number of subjects included in analysis
    82
    Analysis specification
    Pre-specified
    Analysis type
    		 other
    P-value
    		 = 0.078
    Method
    		 Regression, Logistic
    Parameter type
    		 Odds ratio (OR)
    Point estimate
    2.22
    Confidence interval
         level
    		 95%
         sides
    2-sided
         lower limit
    		 0.91
         upper limit
    		 5.37

    Other pre-specified: Change in TMC score from baseline to end of maintenance dose for subjects not taking neuroleptics during the trial (mITT - N=122)

    		 Close Top of page
    End point title
    		 Change in TMC score from baseline to end of maintenance dose for subjects not taking neuroleptics during the trial (mITT - N=122)
    End point description
    Pre-defined sensitivity analysis of the primary efficacy endpoint (change in TMC score from baseline to the end of maintenance dose) was performed in 122 subjects of the mITT not taking neuroleptics during the trial.
    End point type
    Other pre-specified
    End point timeframe
    From baseline to end of maintenance dose (10 weeks of treatment).
    End point values
    		 Placebo SOM3355 400mg/day SOM3355 600mg/day
    Number of subjects analysed
    42
    36
    44
    Units: Change from Baseline
        least squares mean (confidence interval 95%)
    -2.19 (-3.07 to -1.32)
    -2.42 (-3.32 to -1.51)
    -3.46 (-4.35 to -2.58)
    Statistical analysis title
    		 Mixed model for repeated measures (MMRM)
    Comparison groups
    Placebo v SOM3355 600mg/day
    Number of subjects included in analysis
    86
    Analysis specification
    Pre-specified
    Analysis type
    		 other
    P-value
    		 = 0.045
    Method
    		 Mixed models analysis
    Parameter type
    		 Mean difference (final values)
    Point estimate
    -1.27
    Confidence interval
         level
    		 95%
         sides
    2-sided
         lower limit
    		 -2.51
         upper limit
    		 -0.03

    Post-hoc: Change in TMC score from baseline to end of maintenance dose for subjects not taking neuroleptics and with mean baseline TMC score >12 (mITT - N=57)

    		 Close Top of page
    End point title
    		 Change in TMC score from baseline to end of maintenance dose for subjects not taking neuroleptics and with mean baseline TMC score >12 (mITT - N=57)
    End point description
    Post-hoc analysis of the primary efficacy endpoint (change in TMC score from baseline to the end of maintenance dose) was performed in 57 subjects of the mITT not taking neuroleptics during the trial and with a mean baseline TMC score >12.
    End point type
    Post-hoc
    End point timeframe
    From baseline to end of maintenance dose (10 weeks of treatment).
    End point values
    		 Placebo SOM3355 400mg/day SOM3355 600mg/day
    Number of subjects analysed
    21
    14
    22
    Units: Change from baseline
        least squares mean (confidence interval 95%)
    -2.43 (-3.57 to -1.28)
    -2.76 (-4.20 to -1.32)
    -4.21 (-5.36 to -3.06)
    Statistical analysis title
    		 Mixed model for repeated measures (MMRM)
    Comparison groups
    SOM3355 600mg/day v Placebo
    Number of subjects included in analysis
    43
    Analysis specification
    Post-hoc
    Analysis type
    		 other
    P-value
    		 = 0.032
    Method
    		 Mixed models analysis
    Parameter type
    		 Mean difference (final values)
    Point estimate
    -1.78
    Confidence interval
         level
    		 95%
         sides
    2-sided
         lower limit
    		 -3.4
         upper limit
    		 -0.16

    Adverse events

    		 Close Top of page
    Adverse events information
    Timeframe for reporting adverse events
    From Baseline (visit 1) until End of Study visit (up to 13 weeks of treatment).
    Assessment type
    		 Systematic
    Dictionary used for adverse event reporting
    Dictionary name
    		 MedDRA
    Dictionary version
    25.0
    Reporting groups
    Reporting group title
    Placebo
    Reporting group description
    		 -

    Reporting group title
    SOM3355 400mg/day
    Reporting group description
    		 -

    Reporting group title
    SOM3355 600mg/day
    Reporting group description
    		 -

    Serious adverse events
    		 Placebo SOM3355 400mg/day SOM3355 600mg/day
    Total subjects affected by serious adverse events
         subjects affected / exposed
    1 / 48 (2.08%)
    1 / 41 (2.44%)
    1 / 50 (2.00%)
         number of deaths (all causes)
    0
    0
    0
         number of deaths resulting from adverse events
    0
    Nervous system disorders
    Syncope
         subjects affected / exposed
    0 / 48 (0.00%)
    0 / 41 (0.00%)
    1 / 50 (2.00%)
         occurrences causally related to treatment / all
    0 / 0
    0 / 0
    1 / 1
         deaths causally related to treatment / all
    0 / 0
    0 / 0
    0 / 0
    Psychiatric disorders
    Suicidal ideation
         subjects affected / exposed
    1 / 48 (2.08%)
    0 / 41 (0.00%)
    0 / 50 (0.00%)
         occurrences causally related to treatment / all
    1 / 1
    0 / 0
    0 / 0
         deaths causally related to treatment / all
    0 / 0
    0 / 0
    0 / 0
    Infections and infestations
    Pneumonia pneumococcal
         subjects affected / exposed
    0 / 48 (0.00%)
    1 / 41 (2.44%)
    0 / 50 (0.00%)
         occurrences causally related to treatment / all
    0 / 0
    0 / 1
    0 / 0
         deaths causally related to treatment / all
    0 / 0
    0 / 0
    0 / 0
    Frequency threshold for reporting non-serious adverse events: 5%
    Non-serious adverse events
    		 Placebo SOM3355 400mg/day SOM3355 600mg/day
    Total subjects affected by non serious adverse events
         subjects affected / exposed
    10 / 48 (20.83%)
    15 / 41 (36.59%)
    22 / 50 (44.00%)
    Injury, poisoning and procedural complications
    Fall
         subjects affected / exposed
    2 / 48 (4.17%)
    3 / 41 (7.32%)
    4 / 50 (8.00%)
         occurrences all number
    5
    6
    7
    Vascular disorders
    Bradycardia
         subjects affected / exposed
    0 / 48 (0.00%)
    2 / 41 (4.88%)
    6 / 50 (12.00%)
         occurrences all number
    0
    2
    7
    Nervous system disorders
    Somnolence
         subjects affected / exposed
    3 / 48 (6.25%)
    1 / 41 (2.44%)
    3 / 50 (6.00%)
         occurrences all number
    3
    1
    3
    Dizziness
         subjects affected / exposed
    0 / 48 (0.00%)
    4 / 41 (9.76%)
    1 / 50 (2.00%)
         occurrences all number
    0
    4
    1
    General disorders and administration site conditions
    Fatigue
         subjects affected / exposed
    1 / 48 (2.08%)
    0 / 41 (0.00%)
    4 / 50 (8.00%)
         occurrences all number
    1
    0
    4
    Gastrointestinal disorders
    Diarrhoea
         subjects affected / exposed
    3 / 48 (6.25%)
    4 / 41 (9.76%)
    5 / 50 (10.00%)
         occurrences all number
    3
    6
    5
    Vomiting
         subjects affected / exposed
    3 / 48 (6.25%)
    0 / 41 (0.00%)
    1 / 50 (2.00%)
         occurrences all number
    3
    0
    1
    Musculoskeletal and connective tissue disorders
    Back pain
         subjects affected / exposed
    0 / 48 (0.00%)
    3 / 41 (7.32%)
    2 / 50 (4.00%)
         occurrences all number
    0
    3
    2
    Infections and infestations
    Upper respiratory tract infection
         subjects affected / exposed
    0 / 48 (0.00%)
    2 / 41 (4.88%)
    3 / 50 (6.00%)
         occurrences all number
    0
    2
    4

    More information

    		 Close Top of page

    Substantial protocol amendments (globally)
    Were there any global substantial amendments to the protocol? No

    Interruptions (globally)
    Were there any global interruptions to the trial? No

    Limitations and caveats
    Limitations of the trial such as small numbers of subjects analysed or technical problems leading to unreliable data.
    None reported
    For support, Contact us.
    The status and protocol content of GB trials is no longer updated since 1 January 2021. For the UK, as of 31 January 2021, EU Law applies only to the territory of Northern Ireland (NI) to the extent foreseen in the Protocol on Ireland/NI. Legal notice
    As of 31 January 2023, all EU/EEA initial clinical trial applications must be submitted through CTIS . Updated EudraCT trials information and information on PIP/Art 46 trials conducted exclusively in third countries continues to be submitted through EudraCT and published on this website.

    European Medicines Agency © 1995-Mon Jul 07 12:07:23 CEST 2025 | Domenico Scarlattilaan 6, 1083 HS Amsterdam, The Netherlands
    EMA HMA