Researchers sought to examine the minimal clinically important change (MCIC) in total motor Abnormal Involuntary Movement Scale (AIMS) score in patients with tardive dyskinesia (TD) who were treated with deutetrabenazine. Patients in the pooled analysis population consisted of those who were administered the study drug and had at least 1 postbaseline AIMS evaluation in both the ARM-TD and AIM-TD placebo-controlled studies. The US Food and Drug Administration approval of deutetrabenazine was based on these 2 studies.

Patient Global Impression of Change (PGIC) and Clinical Global Impression of Change (CGIC) were used to conduct MCIC analyses. In the analysis, 295 patients were included (deutetrabenazine, n = 197; placebo, n = 98).  MCIC in patients who were treated with deutetrabenazine was -2.4 based on PGIC and -2.1 based on CGIC at Week 12. In patients who were treated with placebo rated minimally improved, mean change in baseline in total motor AIMS score was -1.4 based on PGIC and -1.5 based on CGIC. It was seen that from baseline to Week 12, about 66% and 55% of patients who were given deutetrabenazine achieved an improvement in total motor AIMS score by ≥2 and ≥3 points, respectively. Approximately 41% and 34% of patients in the placebo group saw improvement in total motor AIMS score by ≥2 and ≥3 points, respectively. From utilizing anchor-based methodology, researchers concluded that a decline in total motor AIMS score of approximately 2 is linked to clinically meaningful improvement in symptoms of TD.

Reference: Hauser RA, Barkay H, Wilhelm A, Wieman M, Savola JM, Gordon MF. Minimal clinically important change in Abnormal Involuntary Movement Scale score in tardive dyskinesia as assessed in pivotal trials of deutetrabenazine. Parkinsonism Relat Disord. 2022;97:47-51. doi:10.1016/j.parkreldis.2022.02.017