The primary objective of this study is to evaluate the efficacy of NBI-1065890 compared with placebo for the treatment of tardive dyskinesia (TD) in adult participants.
Medically confirmed diagnosis of schizophrenia, schizoaffective disorder, bipolar disorder, or major depressive disorder (MDD) as defined in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) for at least 3 months prior to screening.
Medically confirmed diagnosis of neuroleptic-induced TD as defined in the DSM-5 for at least 3 months prior to screening.
Moderate or severe TD (AIMS Item 8, severity of abnormal movement overall) as assessed by a blinded, external AIMS video reviewer using a video recording of the participant's AIMS assessment administered at the clinical site by a blinded, certified site AIMS rater. The AIMS dyskinesia total score (sum of Items 1 to 7) must be ≥6 as assessed by the blinded, external AIMS video reviewer.
Comorbid parkinsonism (drug-induced or otherwise) or more than a minimal level of extrapyramidal signs/symptoms, as documented by a score on the Modified Simpson-Angus Scale (mSAS) (excluding Items 8 and 10) >6 at screening or Day -1 (baseline) or a score >3 in any one item (excluding Items 8 and 10).
Barnes Akathisia Rating Scale (BARS) global clinical assessment score ≥2 at screening or Day -1.
Brief Psychiatric Rating Scale (BPRS) total score ≥50 at screening or Day -1.
Hospitalized for schizophrenia, schizoaffective disorder, bipolar disorder, or MDD within 6 months of screening.