Long-Term Efficacy and Safety of Deutetrabenazine in Patients with Tardive Dyskinesia by Concomitant Dopamine-Receptor Antagonist Use

INTRODUCTION: Tardive dyskinesia (TD) is an involuntary movement disorder that can result from exposure to dopamine-receptor antagonists (DRAs). Deutetrabenazine demonstrated significant improvements in Abnormal Involuntary Movement Scale (AIMS) scores in the 12-week pivotal trials (ARM-TD/AIM-TD). This post hoc analysis assessed the long-term efficacy and safety of deutetrabenazine by baseline DRA use. METHODS: Patients who completed ARM-TD or AIM-TD enrolled in the 3-year, open-label extension (OLE) study, with deutetrabenazine dose titrated based on dyskinesia control and tolerability. Change from baseline in total motor AIMS score, Patient Global Impression of Change (PGIC), Clinical Global Impression of Change (CGIC), and adverse event (AE) rates were analyzed in subgroups by baseline DRA use. RESULTS: Of 337 patients in the OLE study, 254 were taking DRAs at baseline (mean age, 56 years; 48% male; 6.0 years since diagnosis) and 83 were not (mean age, 60 years; 31% male; 4.9 years since diagnosis). Mean ± SE dose at week 145 was 39.9 ± 1.0 mg/day in patients taking DRAs (n = 108) and 38.5 ± 1.5 mg/day in patients not taking DRAs (n = 53). At week 145, mean ± SE change from baseline in AIMS score was -6.1 ± 0.43 and -7.5 ± 0.71; 64% and 62% achieved PGIC treatment success; and 69% and 81% achieved CGIC treatment success, respectively. Overall AE incidence was low (exposure-adjusted incidence rates [incidence/patient-years]: any, 1.08 and 1.97; serious, 0.10 and 0.12; leading to discontinuation, 0.06 and 0.05). CONCLUSION: This analysis suggests that deutetrabenazine for long-term treatment of TD is beneficial, with a favorable safety profile, regardless of concomitant DRA use. FUNDING: Teva Pharmaceutical Industries Ltd., Petach Tikva, Israel.