This is a Phase 2b, multicenter, open-label study to evaluate the safety and tolerability of optimized doses of NBI-98854 administered once daily for 24 weeks in pediatric subjects with Tourette Syndrome.

Inclusion Criteria:

1. Have participated in and completed Study NBI-98854-TS2003
2. Have a clinical diagnosis of Tourette Syndrome (TS)
3. If using maintenance medication(s) for TS 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. Adolescent subjects (12 to 18 years of age) must have a negative urine drug screen for amphetamines, barbiturates, benzodiazepine, phencyclidine, cocaine, opiates, or cannabinoids and a negative alcohol screen
6. 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 prior to 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 vesicular monoamine transporter 2 (VMAT2) inhibitors
6. Have a blood loss ≥250 mL or donated blood within 56 days prior to baseline
7. Have a known history of substance (drug) dependence, or substance or alcohol abuse
8. Have a significant risk of suicidal or violent behavior
9. Have received an investigational drug within 30 days before screening or plan to use an investigational drug (other than NBI-98854) during the study