- Subjects must have completed study A8241021
- Diagnosis of HD, including ≥36 CAG repeats.
- Significant neurological disorder other than Huntington's disease.
- WBC ? 3500/mm3 AND/OR ANC ? 2000/mm3 and history of neutropenia or
- Any drug related SAE experienced during study A8241021 which were not approved as
acceptable for enrollment in A8241022.