Using Item 8 of the Abnormal Involuntary Movement Scale (AIMS) to Assess Improvement in Patients with Tardive Dyskinesia

Abstract

Objective

The Abnormal Involuntary Movement Scale (AIMS) total score (sum of items 1–7) is usually the primary efficacy measure in tardive dyskinesia (TD) clinical trials. However, item 8 of the AIMS (clinician’s global impression of severity) might also be an appropriate assessment in real-life healthcare settings. To explore the potential of item 8 as a clinical measure, post hoc analyses were conducted using data from a long-term study of valbenazine, an approved TD medication.

Methods

In KINECT 4 (NCT02405091), adults with TD received once-daily valbenazine (40 or 80 mg) for 48 weeks. Analyses included two sets of AIMS item 8 scores: based on investigators ratings of item 8 using protocol-defined descriptors; and based on investigators highest scores from items 1–7 (analyzed post hoc). Shift analyses included an improvement from score =3 at baseline (moderate or severe) to score =2 at Week 48 (none to mild).

Results

At baseline in all participants (N=163), AIMS item 8 mean scores were 3.2 (protocol) and 3.3 (post hoc). In participants with a score =3 at baseline per investigators ratings using protocol-defined descriptors, 95.9% [94/98] shifted to a score =2 by Week 48. A similar result (93.9% [93/99]) was found when item 8 was based on investigators highest scores from items 1–7.

Conclusion

Shift analyses using AIMS item 8 scores indicated that most participants in KINECT 4 had a clinically meaningful improvement after 48 weeks of once-daily treatment with valbenazine. AIMS item 8 may be an appropriate clinical measure for assessing changes in TD severity.

Funding

Neurocrine Biosciences, Inc.