alternatives for reducing chorea in huntington disease

Conditions: Chorea Associated With Huntington Disease

Summary: the purpose of this study is to evaluate the safety, tolerability, and pharmacokinetics of sd-809 extended release (er) in participants switching from tetrabenazine to sd-809 er. in addition, the safety and tolerability of long-term treatment with sd-809 er will be assessed in "switch" participants as well as "rollover" participants completing a randomized, double blind, placebo-controlled study of sd-809 er.


Eligibility criteria:
inclusion criteria: * participant is at least 18 years of age or the age of majority (whichever is older) at screening. * participant has been diagnosed with manifest hd, as indicated by characteristic motor exam features, and has a documented expanded cytosine adenine guanine (cag) repeat (greater than or equal to \>= \[37\]) at or before screening. * participant meets either of the following: 1. has successfully completed participation in the first-hd study (sd-809-c-15) or 2. has been receiving an food and drug administration (fda)-approved dose of tetrabenazine that has been stable for \>=8 weeks before screening and is providing a therapeutic benefit for control of chorea. * participant has a total functional capacity (tfc) score \>=5 at screening. * participant is able to swallow study medication whole. * participant has provided written, informed consent or, a legally authorized representative (lar) has provided written informed consent and the subject has provided assent. * participant has provided a research advance directive. * female participants of childbearing potential agree to use an acceptable method of contraception from screening through study completion. * the participant has a reliable caregiver who interacts with the participant on a daily basis, oversees study drug administration, assures attendance at study visits and participates in evaluations, as required. * participant is able to ambulate without assistance for at least 20 yards (note: the use of assistive devices (such as; walker, cane) are permitted during ambulation). * has sufficient reading skills to comprehend the participant completed rating scales. exclusion criteria: * participant has a serious untreated or under-treated psychiatric illness, such as depression, at screening or baseline. * participant has active suicidal ideation at screening or baseline. * participant has history of suicidal behavior at screening or baseline. * participant has evidence for depression at baseline. * participant has an unstable or serious medical illness at screening or baseline. * participant has received tetrabenazine within 7 days of baseline (rollover participants only). * participant has received any of the following concomitant medications within 30 days of screening or baseline: antipsychotics, metoclopramide, monoamine oxidase inhibitors (maoi), levodopa or dopamine agonists, reserpine, amantadine, memantine (rollover participants only) * switch participants may receive memantine if on a stable, approved dose for at least 30 days * participant has significantly impaired swallowing function at screening or baseline. * participant has significantly impaired speaking at screening or baseline. * participant requires treatment with drugs known to prolong the qt interval. * participant has prolonged qt interval on 12-lead electrocardiogram (ecg) at screening. * participant has evidence of hepatic impairment at screening. * participant has evidence of significant renal impairment at screening. * participant has known allergy to any of the components of study medication. * participant has participated in an investigational drug or device trial other than sd-809-c-15 within 30 days (or 5 drug half-lives) of screening, whichever is longer. * participant is pregnant or breast-feeding at screening or baseline. * participant acknowledges present use of illicit drugs at screening or baseline. * participant has a history of alcohol or substance abuse in the previous 12 months.

Keywords: chorea huntington disease