A Phase 2 interventional study of Placebo capsules and SOM3355 200 mg capsules in Huntington Chorea, sponsored by SOM Innovation Biotech SA. Completed at 23 sites in 7 countries. Open to participants aged 21 Years and older. Per ClinicalTrials.gov, last updated 2025-08-28.
Sponsored by SOM Innovation Biotech SA · Phase 2, Interventional, and Treatment
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.
293 studies on the registry are indexed under Huntington Disease; 54 are open to participants now.
This study's enrollment of 139 is above the median of 40 across 207 interventional studies indexed under Huntington Disease.
Browse Huntington Disease studies →SOM Innovation Biotech SA is the lead sponsor of 3 studies on the registry; none are open to participants now.
Counted across the registry records on this site, refreshed daily.
Inclusion Criteria: Males or females ≥21 years old, a diagnosis of Huntington's Disease determined by a movement disorders expert and confirmed by a number of HTT gene CAG repeats ≥36, a UHDRS® Total maximal chorea (TMC) score ≥10, and a UHDRS® Total Functional Capacity (TFC) ≥7.
Exclusion Criteria: Onset of HD symptoms prior to age of 21 years (juvenile forms of HD), HD patients presenting rigid akinesia, and use of other VMAT2 inhibitors such as tetrabenazine, deutetrabenazine, or valbenazine, or other antichoreic treatment such as any neuroleptic, or amantadine, memantine, riluzole.
Placebo capsules were administered twice daily (BID) for at least 9 weeks at maintenance dose.
Drug: Placebo capsules
SOM3355 200 mg capsules were administered twice daily (BID) for at least 9 weeks at maintenance dose.
Drug: SOM3355 200 mg capsules
SOM3355 300 mg capsules were administered twice daily (BID) for at least 8 weeks at maintenance dose.
Drug: SOM3355 300 mg capsules
Treatment was blind for the whole duration of the study.
Treatment was blind for the whole duration of the study.
Also known as: Bevantolol hydrochloride
Treatment was blind for the whole duration of the study.
Also known as: Bevantolol hydrochloride
Change in Total Maximal Chorea (TMC) Score of the UHDRS® for Subjects Not Taking Neuroleptics During the Trial (mITT - N=122)
Pre-defined analysis of the primary efficacy endpoint (change in TMC score from baseline to the end of maintenance dose) performed with the 122 subjects of the mITT not taking neuroleptics during the trial. The TMC is part of the motor assessment of the Unified Huntington's Disease Rating Scale (UHDRS) and measures chorea in 7 different body parts, including the face, oral-buccal-lingual region, trunk, and each limb independently. The TMC score is the sum of the individual scores, ranging from 0 to 28. A decrease in TMC scores indicates improvement in chorea symptoms.
Time frame: From baseline to end of maintenance dose (10 weeks of treatment).
Change in the Clinical Global Impression (CGI) (mITT - N=139)
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. Subjects with a score of 1 (Very much improved), 2 (Much improved), or 3 (Minimally improved) were defined as "Improved", and patients with a score of 4 (No change), 5 (Worse), 6 (Much worse), and 7 (Very much worse) were defined as "Not Improved".
Time frame: From baseline to end of maintenance dose (10 weeks of treatment).
Change in the Patient Global Impression (PGI) (mITT - N=139)
Another relevant secondary endpoint was the Patient Global Impression of Change (PGI-C) at Visit 5 (week 10). The efficacy analysis was conducted on the mITT Population, including 139 subjects. Subjects with a score of 1 (Very much improved), 2 (Much improved), or 3 (Minimally improved) were defined as "Improved", and patients with a score of 4 (No change), 5 (Worse), 6 (Much worse), and 7 (Very much worse) were defined as "Not Improved".
Time frame: From baseline to end of maintenance dose (10 weeks of treatment).
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.
| Milestone | Placebo | SOM3355 400 mg/Day | SOM3355 600 mg/Day |
|---|---|---|---|
| Started | 48 | 41 | 50 |
| Completed | 41 | 36 | 41 |
| Not completed | 7 | 5 | 9 |
Pre-defined analysis of the primary efficacy endpoint (change in TMC score from baseline to the end of maintenance dose) performed with the 122 subjects of the mITT not taking neuroleptics during the trial. The TMC is part of the motor assessment of the Unified Huntington's Disease Rating Scale (UHDRS) and measures chorea in 7 different body parts, including the face, oral-buccal-lingual region, trunk, and each limb independently. The TMC score is the sum of the individual scores, ranging from 0 to 28. A decrease in TMC scores indicates improvement in chorea symptoms.
| units on a scale | Placebo | SOM3355 400 mg/Day | SOM3355 600 mg/Day |
|---|---|---|---|
| Change in Total Maximal Chorea (TMC) Score of the UHDRS® for Subjects Not Taking Neuroleptics During the Trial (mITT - N=122) | -2.19 (-3.07 to -1.32) | -2.42 (-3.32 to -1.51) | -3.46 (-4.35 to -2.58) |
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. Subjects with a score of 1 (Very much improved), 2 (Much improved), or 3 (Minimally improved) were defined as "Improved", and patients with a score of 4 (No change), 5 (Worse), 6 (Much worse), and 7 (Very much worse) were defined as "Not Improved".
| Participants | Placebo | SOM3355 400 mg/Day | SOM3355 600 mg/Day |
|---|---|---|---|
| Improved | 15 | 26 | 23 |
| Not Improved | 26 | 11 | 18 |
Another relevant secondary endpoint was the Patient Global Impression of Change (PGI-C) at Visit 5 (week 10). The efficacy analysis was conducted on the mITT Population, including 139 subjects. Subjects with a score of 1 (Very much improved), 2 (Much improved), or 3 (Minimally improved) were defined as "Improved", and patients with a score of 4 (No change), 5 (Worse), 6 (Much worse), and 7 (Very much worse) were defined as "Not Improved".
| Participants | Placebo | SOM3355 400 mg/Day | SOM3355 600 mg/Day |
|---|---|---|---|
| Improved | 20 | 25 | 26 |
| Not Improved | 21 | 12 | 14 |
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. The TMC is part of the motor assessment of the Unified Huntington's Disease Rating Scale (UHDRS) and measures chorea in 7 different body parts, including the face, oral-buccal-lingual region, trunk, and each limb independently. The TMC score is the sum of the individual scores, ranging from 0 to 28. A decrease in TMC scores indicates improvement in chorea symptoms.
| units on a scale | Placebo | SOM3355 400 mg/Day | SOM3355 600 mg/Day |
|---|---|---|---|
| Change in Total Maximal Chorea (TMC) Score for Subjects Not Taking Neuroleptics and With Mean Baseline TMC Score >12 (mITT - N=57) | -2.43 (-3.57 to -1.28) | -2.76 (-4.20 to -1.32) | -4.21 (-5.36 to -3.06) |
Collected over From Baseline (visit 1) until End of Study visit (up to 13 weeks of treatment).. Non-serious events are listed at a 5% frequency threshold.
| Group | Deaths | Serious | Other |
|---|---|---|---|
| Placebo | 0/48 (0%) | 1/48 (2.1%) | 10/48 (20.8%) |
| SOM3355 400 mg/Day | 0/41 (0%) | 1/41 (2.4%) | 15/41 (36.6%) |
| SOM3355 600 mg/Day | 0/50 (0%) | 1/50 (2%) | 22/50 (44%) |
| Event | Placebo | SOM3355 400 mg/Day | SOM3355 600 mg/Day |
|---|---|---|---|
| Pneumonia pneumococcalInfections and infestations | 0/48 | 1/41 | 0/50 |
| Suicidal ideationPsychiatric disorders | 1/48 | 0/41 | 0/50 |
| Syncope (overdose)Nervous system disorders | 0/48 | 0/41 | 1/50 |
| Event | Placebo | SOM3355 400 mg/Day | SOM3355 600 mg/Day |
|---|---|---|---|
| BradycardiaVascular disorders | 0/48 | 2/41 | 6/50 |
| DiarrheaGastrointestinal disorders | 3/48 | 4/41 | 5/50 |
| DizzinessNervous system disorders | 0/48 | 4/41 | 1/50 |
| FallInjury, poisoning and procedural complications | 2/48 | 3/41 | 4/50 |
| FatigueGeneral disorders | 1/48 | 0/41 | 4/50 |
| Back painMusculoskeletal and connective tissue disorders | 0/48 | 3/41 | 2/50 |
| SomnolenceNervous system disorders | 3/48 | 1/41 | 3/50 |
| VomitingGastrointestinal disorders | 3/48 | 0/41 | 1/50 |
| Upper respiratory tract infectionInfections and infestations | 0/48 | 2/41 | 3/50 |
| Age, Categorical(Participants) | Placebo | SOM3355 400 mg/Day | SOM3355 600 mg/Day | Total |
|---|---|---|---|---|
| <=18 years | 0 | 0 | 0 | 0 |
| Between 18 and 65 years | 43 | 32 | 45 | 120 |
| >=65 years | 5 | 9 | 5 | 19 |
| Age, Continuous(years) | Placebo | SOM3355 400 mg/Day | SOM3355 600 mg/Day | Total |
|---|---|---|---|---|
| Mean | 51.65 ± 10.46 | 52.51 ± 12.39 | 51.34 ± 12.12 | 51.79 ± 11.58 |
| Sex: Female, Male(Participants) | Placebo | SOM3355 400 mg/Day | SOM3355 600 mg/Day | Total |
|---|---|---|---|---|
| Female | 28 | 17 | 21 | 66 |
| Male | 20 | 24 | 29 | 73 |
| Race/Ethnicity, Customized(Participants) | Placebo | SOM3355 400 mg/Day | SOM3355 600 mg/Day | Total |
|---|---|---|---|---|
| Ethnic Origin — White | 48 | 39 | 48 | 135 |
| Ethnic Origin — African (North) | 0 | 1 | 1 | 2 |
| Ethnic Origin — Latino | 0 | 1 | 0 | 1 |
| Ethnic Origin — Other (in France) | 0 | 0 | 1 | 1 |
| Region of Enrollment(participants) | Placebo | SOM3355 400 mg/Day | SOM3355 600 mg/Day | Total |
|---|---|---|---|---|
| Poland | 8 | 9 | 9 | 26 |
| Italy | 5 | 6 | 8 | 19 |
| United Kingdom | 7 | 4 | 7 | 18 |
| France | 7 | 2 | 6 | 15 |
| Switzerland | 2 | 1 | 2 | 5 |
| Germany | 7 | 7 | 7 | 21 |
| Spain | 12 | 12 | 11 | 35 |
| Use of Neuroleptics(Participants) | Placebo | SOM3355 400 mg/Day | SOM3355 600 mg/Day | Total |
|---|---|---|---|---|
| Yes | 6 | 5 | 6 | 17 |
| No | 42 | 36 | 44 | 122 |
| Total Maximal Chorea (TMC) score(units on a scale) | Placebo | SOM3355 400 mg/Day | SOM3355 600 mg/Day | Total |
|---|---|---|---|---|
| Mean | 12.80 ± 2.58 | 12.74 ± 2.93 | 13.23 ± 2.84 | 12.94 ± 2.77 |
PDFs hosted by the registry, ClinicalTrials.gov.
Plan to share: Undecided
Ran from Aug 2022 to primary completion in Jun 2024, 22 months.
Results were first posted in Aug 2025, 1 year 2 months after primary completion.
Of 22 phase 2 interventional studies under Huntington Disease, half reached primary completion within 31 months of starting (the median), counting those still running; a quarter within 21 and three quarters within 40. This study's 22 months is below that.
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