Alternatives for Reducing Chorea in Huntington’s Disease (ARC-HD)

ARC-HD is an open label long term safety and tolerability clinical research trial of an investigational drug called SD-809 Extended Release (ER) in persons who have a diagnosis of Huntington disease (HD). ARC-HD will look at how safe, tolerable and effective SD-809 ER is in HD subjects who switch from tetrabenazine to SD-809ER. ARC-HD will be enrolling participants across 8 sites in the United States who have been diagnosed with HD and who are either currently taking tetrabenazine (Xenazine ®) or have recently completed the FIRST-HD trial. Subjects will be involved in this trial for up to 14 months and will remain on study drug for a total of 54 weeks.

The ARC-HD Trial is being conducted by the Huntington Study Group (HSG) under the leadership of Samuel Frank, MD, Principal Investigator, (Boston University School of Medicine) and Claudia Testa, MD, PhD, co-Principal Investigator (Virginia Commonwealth University). Approximately 8 HSG research sites across the United States and Canada will enroll about 36 people with HD. 

For more information please visit:

Or, visit the ARC-HD page on at:

A list of ARC-HD sites and contact information can be found at: