- Must have a diagnosis of Huntington's Disease
- a CAG repeat expansion equal or great than 39
- a Unified Huntington Disease Rating Scale (UHDRS) Total Motor Score equal or greater
than 5 and less than 60
- a UHDRS Total Functional Capacity equal or greater than 9
- Subjects with evidence or history of severe acute or chronic medical condition or
laboratory abnormality, or significant neurological disorder other than HD.
- Treatment with any antipsychotic medication within 5 weeks of enrollment