NBI‐98854, a selective monoamine transport inhibitor for the treatment of tardive dyskinesia: A randomized, double‐blind, placebo‐controlled study

BACKGROUND: Tardive dyskinesia is a persistent movement disorder induced by chronic neuroleptic exposure. NBI‐98854 is a novel, highly selective, vesicular monoamine transporter 2 inhibitor. We present results of a randomized, 6‐week, double‐blind, placebo‐controlled, dose‐titration study evaluating the safety, tolerability, and efficacy of NBI‐98854 for the treatment of tardive dyskinesia. METHODS: Male and female adult subjects with moderate or severe tardive dyskinesia were included. NBI‐98854 or placebo was given once per day starting at 25 mg and then escalated by 25 mg to a maximum of 75 mg based on dyskinesia and tolerability assessment. The primary efficacy endpoint was the change in Abnormal Involuntary Movement Scale from baseline at week 6 scored by blinded, central video raters. The secondary endpoint was the Clinical Global Impression of Change—Tardive Dyskinesia score assessed by the blinded investigator. RESULTS: Two hundred five potential subjects were screened, and 102 were randomized; 76% of NBI‐98854 subjects and 80% of placebo subjects reached the maximum allowed dose. Abnormal Involuntary Movement Scale scores for NBI‐98854 compared with placebo were significantly reduced (p = 0.0005). Active drug was also superior on the Clinical Global Impression of Change—Tardive Dyskinesia (p < 0.0001). Treatment‐emergent adverse event rates were 49% in the NBI‐98854 and 33% in the placebo subjects. The most common adverse events (active vs. placebo) were fatigue and headache (9.8% vs. 4.1%) and constipation and urinary tract infection (3.9% vs. 6.1%). No clinically relevant changes in safety assessments were noted. CONCLUSION: NBI‐98854 significantly improved tardive dyskinesia and was well tolerated in patients. These results support the phase 3 clinical trials of NBI‐98854 now underway. © 2015 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.