Neurocrine Biosciences has started a Phase II clinical trial of NBI-98854 (Valbenazine), a highly selective small molecule Vesicular Monoamine Transporter 2 (VMAT2) inhibitor, to treat Tourette syndrome in adults.
VMAT2 is a protein concentrated in the human brain that is primarily responsible for re-packaging and transporting monoamines in pre-synaptic neurons.
The initiation of this trial has expanded the clinical efforts for NBI-98854 in adults with Tourette syndrome.
Around 90 adults will be enrolled in this randomised, double-blind, placebo-controlled, multi-dose, parallel group Phase II trial (T-Forward study).
In the trial, patients will receive once-daily dosing of NBI-98854 during an eight-week treatment period to evaluate the safety, tolerability and efficacy of the VMAT2 inhibitor.
The trial's primary endpoint is a change from baseline of placebo versus active scores using the Yale Global Tic Severity Scale at the end of week eight.
Results from this trial are expected to be reported later in 2016.
Neurocrine Biosciences chief medical officer Dr Christopher O'Brien said: "Evaluation of Valbenazine in adults with Tourette syndrome is another important step in fully exploring its potential in movement disorders.
"We look forward to our T-Force study readout of children and adolescents with Tourette's during this quarter, and our anticipated NDA filing of NBI-98854 for tardive dyskinesia in 2016."
The three-arm trial will evaluate up to 90 patients over eight weeks of dosing followed by two weeks off-drug at approximately 40 study centres in the US.
Tourette symptoms, a neurological disorder, will also be evaluated through the Premonitory Urge for Tics Scale, as well as Clinical Global Impression of Change scales, among others.
This disorder consists of rapid, non-rhythmic stereotyped motor and vocal tics.
The company has two distinct investigational new drug applications (INDAs) related to NBI-98854, tardive dyskinesia and Tourette syndrome, open with the Division of Psychiatry Products at the FDA.
The FDA has granted breakthrough therapy designation for NBI-98854 in the treatment of tardive dyskinesia and expects to file a new drug application (NDA) for tardive dyskinesia in 2016.