Study stopped early due to investigational drug not meeting primary endpoint in the main study T-Force GOLD (NBI-98854-TS2003); no safety concerns identified.

This is an open-label, rollover study to collect long-term safety, tolerability, and investigator- and participant-reported pharmacodynamic (PD) data after chronic administration of NBI-98854 in pediatric participants with Tourette Syndrome (TS), as well as to provide open-label access to NBI-98854 for the treatment of TS for pediatric participants who have taken part in a Phase 2 NBI-98854 study.

Inclusion Criteria:

1. Have a clinical diagnosis of Tourette Syndrome (TS)
2. Have participated in the NBI-98854-TS2004 or NBI 98854-TS2005 Phase 2 studies
3. If using maintenance medication(s) for TS and/or TS spectrum diagnoses (e.g. obsessive-compulsive disorder [OCD], Attention-Deficit Hyperactivity Disorder [ADHD]), be on stable doses
4. Be in good general health
5. Subjects of childbearing potential who do not practice total abstinence must agree to use hormonal or two forms of nonhormonal contraception (dual contraception) consistently during the screening, treatment and follow-up periods of the study

Exclusion Criteria:

1. Have an active, clinically significant unstable medical condition within 1 month before screening
2. Have a known history of long QT syndrome or cardiac arrhythmia
3. Have a known history of neuroleptic malignant syndrome
4. Have a cancer diagnosis within 3 years prior to screening (some exceptions allowed)
5. Have an allergy, hypersensitivity, or intolerance to VMAT2 inhibitors
6. Have a blood loss ≥250 mL or donated blood within 56 days, or donated plasma within 7 days, before the start of the study
7. Have a known history of substance dependence, substance (drug) or alcohol abuse within 3 months before the start of the study
8. Have a significant risk of suicidal or violent behavior
9. Have received an investigational drug within 30 days before the start of the study or plan to use an investigational drug (other than NBI-98854) during the study
10. Are currently participating in another NBI-98854 clinical study
11. Are pregnant (for females)