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Involuntary choreatic movements in Huntington disease (HD) can be treated symptomatically and pathways to manage chorea are available.1,2 However, all current treatments of chorea are accompanied by relevant adverse effects and thus better alternatives are desirable. Drugs prescribed to reduce chorea are usually neuroleptics or tetrabenazine. So far, first-line use by experts favors neuroleptics about 2:1 over tetrabenazine with regional differences: neuroleptics are clearly first choice in Europe, while a nearly similar level of first-line use of tetrabenazine is seen in North America and Australia.2 Of note, tetrabenazine is the only drug formally approved by the US Food and Drug Administration for the treatment of chorea in HD based on the results of a randomized placebo-controlled clinical trial: the Study of Tretrabenazine in Patients with Huntington’s Disease (TETRA-HD) was conducted by the investigators of the Huntington Study Group (http://www.huntingtonstudygroup.org) and demonstrated a reduction (ie, improvement) of the total maximal chorea (TMC) score of −3.5 points compared with placebo.3 The TMC (range, 0-28) is a subscore of the Unified Huntington’s Disease Rating Scale Total–Motor Score (UHDRS-TMS) assessing chorea in 7 body regions, each of which is assigned a grade of 0 to 4 for severity of chorea, with higher numbers indicating more severe chorea.
Reilmann R. Deutetrabenazine—Not a Revolution but Welcome Evolution for Treating Chorea in Huntington Disease. JAMA Neurol. Published online October 17, 2016. doi:10.1001/jamaneurol.2016.3916