
    futility
  
['tourette syndrome']
['valbenazine', 'placebo oral capsule']

        Inclusion Criteria:

          1. Have a clinical diagnosis of Tourette Syndrome (TS)

          2. Have at least moderate tic severity

          3. Have TS symptoms that impair school, occupational, and/or social function

          4. 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

          5. Be in good general health

          6. Adolescent subjects (12 to 17 years of age) must have a negative urine drug screen for
             amphetamines, barbiturates, benzodiazepine, phencyclidine, cocaine, opiates, or
             cannabinoids and a negative alcohol screen

          7. 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 VMAT2 inhibitors

          6. Have a blood loss ≥250 mL or donated blood within 30 days prior to screening

          7. Have a known history of substance dependence, substance (drug) or alcohol abuse

          8. Have a significant risk of suicidal or violent behavior

          9. Have initiated Comprehensive Behavioral Intervention for Tics (CBIT) during the
             screening period or at baseline or plan to initiate CBIT during the study

         10. Have received an investigational drug within 30 days before screening or plan to use
             an investigational drug (other than NBI-98854) during the study

         11. Have previously participated in an NBI-98854 clinical study, except for NBI-98854-1403
             or NBI-98854-1501.

         12. Have HIV, hepatitis B, or hepatitis C
      