The US Food and Drug Administration has assigned Teva’s SD-809 Breakthrough Therapy Designation for the treatment of patients with moderate-to-severe tardive dyskinesia, a hyperkinetic movement disorder affecting about 500,000 people in the US.

The condition, for which there are no approved therapies in the US, 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.

SD-809 (deutetrabenazine) 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.

The Breakthrough badge came on the back of data from Teva’s Phase II/III study, Aim to Reduce Movements in Tardive Dyskinesia (ARM-TD), in which SD-809 was compared to placebo for change in Abnormal Involuntary Movement Scale (AIMS) score from baseline to end of therapy.

Results show patients that patients taking SD-809 achieved an improvement of 3.0 points on the AIMS score from baseline to end of therapy compared to 1.6 points in placebo for a clinically meaningful effect. A favourable safety and tolerability profile was also reported. 

The drug, which Teva acquired through its purchase of Auspex, is already under FDA review for Huntington's disease and is also being developed for Tourette’s.