Background: The 12-week ARM-TD and AIM-TD studies in tardive dyskinesia (TD) patients showed statistically significant improvements in TD symptoms with deutetrabenazine. The completed open-label extension (OLE) study (SD-809-C-20) evaluated long-term efficacy and safety of deutetrabenazine in TD.
Methods: Patients who completed ARM-TD or AIM-TD enrolled in the OLE study, with deutetrabenazine dose titrated based on dyskinesia control and tolerability. Change from baseline in Abnormal Involuntary Movement Scale (AIMS) score was assessed by local site raters. Treatment success was evaluated locally as patients being Much Improved or Very Much Improved on Clinical Global Impression of Change (CGIC).
Results: 343 patients enrolled in the OLE study; 6 patients were excluded from analyses. At Week 54 (n=249; dose mean[SE]: 38.7(0.66)mg/day), mean change from baseline in AIMS score was -4.8(0.28); 66% of patients experienced treatment success. At Week 106 (n=194; dose: 39.3(0.75)mg/day), mean change from baseline in AIMS score was -5.4(0.33); 65% of patients experienced treatment success. At Week 145 (n=160; dose: 39.4(0.83)mg/day), mean change from baseline in AIMS score was -6.6(0.37); 73% of patients experienced treatment success. Treatment was generally well tolerated across 688 patient-years of exposure through Week 158, and exposure-adjusted incidence rates (incidence/patient-years) for akathisia/restlessness were 0.01, somnolence/sedation were 0.07, and symptoms which may represent parkinsonism or depression were 0.08 each.
Conclusions: Patients who received long-term treatment with deutetrabenazine achieved sustained improvement in AIMS scores. Findings from this open-label trial with response-driven dosing suggest the possibility of increasing benefit over time.