Background: Tardive dyskinesia (TD) is a movement disorder that may intensify the stigma of patients with psychiatric disorders. In the ARM-TD and AIM-TD trials (parent studies), deutetrabenazine (DTB) significantly improved TD symptoms versus placebo and was well tolerated.
Objective: To evaluate the long-term efficacy of DTB.
Methods: Patients who completed the parent studies were included in this open-label, long-term extension comprising a 6-week titration period (from 12 mg/day to a maximum of 48 mg/day) followed by a long-term maintenance phase. Efficacy was assessed by site-rated Abnormal Involuntary Movement Scale (AIMS) scores, and the treatment success rate on the Clinical Global Impression of Change (CGIC) and Patient Global Impression of Change (PGIC).
Results: At the end of the parent studies (Week 12), AIMS score (mean [standard error]; –5.0 [0.40]) versus placebo (–3.2 [0.47]) improved with DTB. Long-term DTB treatment improved AIMS (prior DTB, –7.9 [0.62]; prior placebo, –6.6 [0.64]) score compared with parent study baseline. Similarly, at the end of the parent studies, treatment success rates were higher for DTB on the CGIC (51%) and the PGIC (46%) than placebo (32% and 33%, respectively), whereas the treatment success rates on CGIC (prior DTB: 66%; prior placebo: 68%) and PGIC (prior DTB: 62%; prior placebo: 62%) were similar in both groups at Week 54. DTB was generally well tolerated.
Conclusions: DTB improved TD as measured by site-rated AIMS, CGIC, and PGIC scores, consistent with previously reported DTB efficacy in the parent studies where central raters were used to evaluate AIMS scores.