Drug candidate fails to improve symptoms of fragile X syndrome

An experimental drug for the genetic disorder fragile X syndrome has proven ineffective in two studies in people.

The syndrome, which is caused by a mutation on the X chromosome, can cause intellectual disability, attention deficit disorder and autism spectrum disorders.

The drug candidate, called mavoglurant, had shown promise in mice with a genetic condition similar to fragile X. The drug suppresses the activity of the protein mGluR5, thought to play a role in altering brain cell structure in patients with fragile X syndrome (SN: 6/2/12, p. 17).   

But in 12-week clinical trials in people, mavoglurant did not improve behavioral symptoms such as irritability or hyperactivity in 175 adults and 139 adolescents with fragile X syndrome, researchers report January 13 in Science Translational Medicine.

Future trials might show improved results from testing the drug candidate in even younger patients or over much longer periods of time, the scientists say.