A Study of RG1662 in Adults and Adolescents With Down Syndrome (CLEMATIS)

A MULTI-CENTER, RANDOMIZED, DOUBLE-BLIND, PLACEBO-CONTROLLED PHASE 2 STUDY OF THE EFFICACY, SAFETY AND TOLERABILITY OF RG1662 IN ADULTS AND ADOLESCENTS WITH DOWN SYNDROME (CLEMATIS)

Status

Completed

Phases

Phase 2

Study type

Interventional

Source

ClinicalTrials.gov

Registry ID

NCT02024789

Enrollment

173

Registered

2013-12-31

Start date

2014-05-05

Completion date

2016-05-04

Last updated

2017-10-25

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Down Syndrome

Brief summary

This multi-center, randomized, double-blind, 3-arm, parallel-group, placebo-controlled study will evaluate the efficacy and safety of RG1662 in adults and adolescents with Down syndrome. Subjects will be randomized to receive RG1662 either at low or high dose or placebo orally twice daily for 26 weeks.

Interventions

DRUGPlacebo

Orally twice daily, 26 weeks

DRUGRG1662

120 mg (80 mg for subjects 12 and 13 years of age) orally twice daily, 26 weeks

Study design

Allocation

RANDOMIZED

Intervention model

PARALLEL

Primary purpose

TREATMENT

Masking

DOUBLE (Subject, Investigator)

Eligibility

Sex/Gender

ALL

Age

12 Years to 30 Years

Healthy volunteers

Inclusion criteria

* Individuals aged 12-30 years of age inclusive * Clinical diagnosis of Down syndrome (trisomy 21) confirmed by chromosomal analysis (karyotyping) * Males, or non-pregnant, non-lactating females. For females of childbearing potential, strict contraceptive prevention is required. * Body-mass Index (BMI) 18-42 and 15-30 kg/m2 inclusive for adults and adolescents respectively * Ability to complete the Clinical Evaluation of Language Fundamentals (CELF)-preschool 2 word classes task * Subjects must have a parent, or other reliable caregiver who agrees to accompany the subject to all clinic visits, provide information about the subject as required by the protocol, and ensure compliance with the medication schedule * Study participants must have sufficient language, vision and hearing to participate in study evaluations, as judged clinically by investigator

Exclusion criteria

* Subjects with a current DSM 5 diagnosis of any primary psychiatric diagnosis (including ASD or MDD) * Subjects with a history of infantile spasms, of West syndrome, Lennox-Gastaut syndrome, Early Infantile Epileptic Encephalopathy or any treatment-refractory epilepsy associated with cognitive or developmental regression, of severe head trauma or CNS infections (e.g. meningitis) * Subjects with a known or suspected clinical seizure event of any type within 24 months prior to screening * Clinically relevant ECG abnormalities at screening or baseline; QTcF above 450 ms; personal or family history (first degree relatives) of congenital long QT syndrome * Inadequate renal or hepatic function

Design outcomes

Primary

Measure	Time frame
Cognition as assessed by the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) sub-tests	26 weeks
Adaptive behavior as assessed by the Vineland Adaptive Behavior Scales-II (VABS-II) standard scores	26 weeks
Clinical global impression as assessed by Clinician Rated Global Improvement (CGI-I) scale	26 weeks

Secondary

Measure	Time frame
Incidence of abnormal ECG changes	26 weeks
Abnormal ECG changes in adolescents as compared to baseline	from baseline to Week 26
Safety: Incidence of adverse events	approximately 32 weeks
Incidence of abnormal blood pressure	26 weeks
RG1662 plasma concentrations	26 weeks

Countries

Argentina, Canada, France, Italy, Mexico, New Zealand, Singapore, Spain, United Kingdom, United States

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 13, 2026