Phase 2 N=139 Randomized Quadruple-blind Treatment

Efficacy and Safety on SOM3355 in Huntington's Disease Chorea

Huntington Chorea

Bottom Line

View on ClinicalTrials.gov: NCT05475483 ↗

Enrolled (actual)

139

Serious AEs

2.2%

Results posted

Aug 2025

Primary outcome: Primary: Change in Total Maximal Chorea (TMC) Score of the UHDRS® for Subjects Not Taking Neuroleptics During the Trial (mITT - N=122) — -2.19; -2.42; -3.46 units on a scale — p== 0.045

Study Design & Population

Study type: Interventional
Phase: Phase 2
Interventions: Placebo capsules (Drug); SOM3355 200 mg capsules (Drug); SOM3355 300 mg capsules (Drug)
Age: Adult, Older Adult · 21+ yrs
Sex: All
Sponsor: SOM Innovation Biotech SA
Primary completion: Jun 2024

Outcome Measures

Outcome	Result	p-value
PRIMARY Change in Total Maximal Chorea (TMC) Score of the UHDRS® for Subjects Not Taking Neuroleptics During the Trial (mITT - N=122)	-2.19; -2.42; -3.46	= 0.045 sig
SECONDARY Change in the Clinical Global Impression (CGI) (mITT - N=139)	15; 26; 23; 26; 11; 18	= 0.078
SECONDARY Change in the Patient Global Impression (PGI) (mITT - N=139)	20; 25; 26; 21; 12; 14	0.143

Summary

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.

Eligibility Criteria

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.

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Data sourced from ClinicalTrials.gov (NCT05475483). Outcome figures and adverse-event rates are extracted automatically from the registry's posted results and are provided for clinician reference, not as a substitute for the primary publication.