SD-809 is an investigational, oral, small molecule inhibitor of vesicular monoamine 2 transporter, or VMAT2, that is designed to regulate the levels of a specific neurotransmitter, dopamine, in the brain.
For SD-809, the breakthrough designation request included results from the company's Phase II/III trial, aim to reduce movements in tardive dyskinesia (ARM-TD).
In this trial, SD-809 was compared to placebo for change in abnormal involuntary movement scale (AIMS) score from baseline to end of therapy.
A total of 117 patients with moderate to severe tardive dyskinesia were included in the 1:1 randomised, double-blind, placebo-controlled, parallel-group ARM-TD trial.
These patients were given either SD-809 or placebo, which was titrated to optimal dosage over the course of six weeks, and then administered at that dose for another six weeks for a total treatment of 12 weeks.
Teva Global R&D president and chief scientific officer Michael Hayden said: "The granting of Breakthrough Therapy Designation by the FDA represents significant progress toward advancing the clinical programme for SD-809, as a potential, much-needed treatment option for the undeserved tardive dyskinesia patient population."
Tardive dyskinesia, for which there are no approved therapies in the US, affects about 500,000 people in the country.
It is characterised by repetitive and uncontrollable movements of the tongue, lips, face, and extremities and has been reported with some widely used medications for psychiatric conditions such as schizophrenia and bipolar disease, as well as with certain drugs used for treating various gastrointestinal disorders.
The objectives of the ARM-TD trial were to evaluate the efficacy of SD-809 in reducing the severity of abnormal involuntary movements associated with tardive dyskinesia.
The trial was also designed to evaluate the safety and tolerability of titration and maintenance therapy with SD-809 in subjects with tardive dyskinesia.
