The purpose of this study is to evaluate the efficacy, safety, and tolerability of two doses (50 and 100 mg) of NBI-98854 administered once daily for the treatment of Tardive Dyskinesia (TD) symptoms.

This is a Phase 2, multicenter, randomized, double-blind, placebo-controlled, parallel group study to evaluate the efficacy, safety, and tolerability of two doses (50 and 100 mg) of NBI-98854 administered once daily for up to 2 weeks. The study will also allow for an evaluation of the efficacy of NBI-98854 50 mg once daily for up to 6 weeks and the safety and tolerability of NBI 98854 50 mg once daily for up to 12 weeks.

The double-blind placebo-controlled treatment period the study has three arms:

• NBI-98854 50 mg once daily for 6 weeks
• NBI-98854 100 mg once daily for 2 weeks followed by 50 mg once daily for the remaining 4 weeks
• placebo

At the end of the 6-week placebo-controlled double-blind treatment period, subjects will continue in the study for an additional 6-week open-label period where all subjects who have completed the double-blind treatment period will receive NBI-98854 50 mg once daily. Two and four weeks after the last dose of study drug, follow-up assessments will be performed.

Inclusion Criteria:

• Have a clinical diagnosis of schizophrenia or schizoaffective disorder and a clinical diagnosis of neuroleptic-induced tardive dyskinesia for at least 3 months prior to screening.
• Be receiving a stable dose of antipsychotic medication for a minimum of 30 days before study start. Subjects who are not using antipsychotic medication must have stable psychiatric status.
• Have the doses of concurrent medications and the conditions being treated be stable for a minimum of 30 days before study start and be expected to remain stable during the study.
• Subjects of childbearing potential must agree to use hormonal or two forms of nonhormonal birth control during the study.
• Female subjects must not be pregnant.
• Be in good general health and expected to complete the clinical study as designed.
• Have a body mass index (BMI) of 18 to 38 kg/m2 (both inclusive).
• Have a negative urine drug screen (negative for amphetamines, barbiturates, benzodiazepine, phencyclidine, cocaine, opiates, or cannabinoids) at screening and study start, except for any subject receiving a stable dose of benzodiazepine.
• Have a negative alcohol breath test at screening and study start.

Exclusion Criteria:

• Have an active clinically significant unstable medical condition within 1 month (30 days) prior to screening.
• Have a history of substance dependence or substance (drug) or alcohol abuse within the 3 months before study start(nicotine and caffeine dependence are not exclusionary).
• Have a known history of neuroleptic malignant syndrome.
• Have a significant risk of suicidal or violent behavior.
• Receiving any excluded concomitant medication such as reserpine, metoclopramide, stimulants, or tetrabenazine.
• Receiving medication for the treatment of tardive dyskinesia.
• Have a positive human immunodeficiency virus antibody, (HIV-Ab), hepatitis B surface antigen (HBsAg), or hepatitis C virus (HCV) antibody result at screening or have a history of positive result.
• Have received an investigational drug within 30 days before screening or plan to use an investigational drug (other than NBI-98854) during the study.
• Have an allergy, hypersensitivity, or intolerance to tetrabenazine.
• Have had previous exposure with NBI-98854.