Statement on CLEMATIS trialLogo Roche

June 28, 2016

The CLEMATIS trial was a Phase II study investigating the efficacy and safety of basmisanil (RG1662) in adults and adolescents with Down syndrome. It was a 26 week, multi-centre, randomized, double-blind, three arm, parallel-group, placebo-controlled study.

This phase II study did not meet its primary and secondary endpoints on improvement in cognition and function. There was no difference observed between adults (18-30 years old) and adolescent (12-17 years old) in the study. In addition, there was no significant difference between those who took the drug and those that took the placebo.

Given the lack of efficacy seen in the CLEMATIS trial, Roche has decided to discontinue the ongoing clinical trial (WP28760) in children (6-11 years old) with Down syndrome. This paediatric study is not being discontinued for safety reasons as basmisanil was well tolerated and no relevant safety signals were observed with basmisanil when compared to placebo and previous trials.

We are disappointed by the lack of efficacy seen in the CLEMATIS trial. We have learnt a lot from people with Down syndrome and their families over the past few years and we are very grateful for their willingness to participate in this clinical trial programme.

We are committed to sharing our learnings with the community and the results of the CLEMATIS trial will be presented at an upcoming medical congress as well as being posted on