Efficacy and Safety on SOM3355 in Huntington's Disease Chorea

Phase 2

Completed

• Conditions: Huntington Chorea
• Interventions: Drug: Placebo capsules; Drug: SOM3355 200 mg capsules; Drug: SOM3355 300 mg capsules

• Registration Number: NCT05475483
• Lead Sponsor: SOM Innovation Biotech SA

Brief 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.

Detailed Description

Not available

Study Timeline

• Study First Submitted: 2022-07-22
• Study First Submitted QC: 2022-07-26
• Study First Posted: 2022-07-27
• Study Start: 2022-08-02
• Primary Completion: 2024-06-25
• Study Completion: 2024-07-15
• Results First Submitted: 2025-07-09
• Status Verified: 2025-08
• Results First Submitted QC: 2025-08-27
• Last Update Submitted: 2025-08-27
• Results First Posted: 2025-08-28
• Last Update Posted: 2025-08-28

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 139

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.

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Placebo	Placebo capsules	Placebo capsules were administered twice daily (BID) for at least 9 weeks at maintenance dose.
SOM3355 400 mg/day	SOM3355 200 mg capsules	SOM3355 200 mg capsules were administered twice daily (BID) for at least 9 weeks at maintenance dose.
SOM3355 600 mg/day	SOM3355 300 mg capsules	SOM3355 300 mg capsules were administered twice daily (BID) for at least 8 weeks at maintenance dose.

Primary Outcome Measures

Name	Time	Method
Change in Total Maximal Chorea (TMC) Score of the UHDRS® for Subjects Not Taking Neuroleptics During the Trial (mITT - N=122)	From baseline to end of maintenance dose (10 weeks of treatment).	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.

Secondary Outcome Measures

Name	Time	Method
Change in the Clinical Global Impression (CGI) (mITT - N=139)	From baseline to end of maintenance dose (10 weeks of treatment).	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".
Change in the Patient Global Impression (PGI) (mITT - N=139)	From baseline to end of maintenance dose (10 weeks of treatment).	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".

Trial Locations

Locations (23)

Centre Hospitalier Universitaire Angers; 🇫🇷 Angers, France

CHU Hôpital Henri Mondor (APHP); 🇫🇷 Créteil, France

Hôpital Roger Salengro - CHU Lille; 🇫🇷 Lille, France

Hopital de Hautepierre; 🇫🇷 Strasbourg, France

Hôpital Purpan - CHU Toulouse; 🇫🇷 Toulouse, France

Charité - Universitätsmedizin Berlin; 🇩🇪 Berlin, Germany

George Huntington Institut; 🇩🇪 Münster, Germany

Kbo-Isar-Amper-Klinikum Taufkirchen; 🇩🇪 Taufkirchen, Germany

Hospital of University of Ulm; 🇩🇪 Ulm, Germany

IRCCS Istituto delle Scienze Neurologiche di Bologna; 🇮🇹 Bologna, Italy

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