Joel Yager, MD reviewing Hauser RA et al. Am J Psychiatry 2017 Mar 21.

Valbenazine, a vesicular monoamine transporter 2 inhibitor, had a favorable benefit vs. harm profile for reducing tardive dyskinesia.

Currently, no medications are FDA-approved for tardive dyskinesia, although several, including tetrabenazine (a vesicular monoamine transporter 2 [VMAT2] inhibitor approved for treating hyperkinetic symptoms in Huntington disease), have been used off label. In an industry-sponsored, multisite, phase-3, double-blind trial, researchers randomized 234 patients with tardive dyskinesia (mean age, 56; men, 54%) to 6 weeks of valbenazine (an experimental VMAT2 inhibitor) at 40 mg, valbenazine at 80 mg, or placebo.

Patients had stable schizophrenia, schizoaffective disorder, or mood disorder; tardive dyskinesia had lasted at least 3 months. Exclusion criteria included medical instability and other prominent neurological disorders (e.g., parkinsonism, akathisia, or truncal dystonia). Stable medications for psychiatric and general medical conditions were continued. Almost 90% of patients completed the trial.

Based on assessment of patients' videos, valbenazine at 6 weeks produced significant improvement compared with placebo on the Abnormal Involuntary Movement Scale (AIMS) at both the 80-mg dose (mean AIMS reductions, 3.2 vs. 0.1 with placebo; number needed to treat for one to benefit [NNT], 4; number needed to harm [NNH], 13) and the 40-mg dose (mean AIMS reductions; 1.9 vs. 0.1; NNT, 7; NNH, −32 [the negative value indicates fewer adverse effects with valbenazine than placebo]). Psychiatric symptoms remained stable. Treatment-emergent adverse effects, occurring in ≤5% of any group, were primarily somnolence, akathisia, and dry mouth.

CITATION(S):

Hauser RA et al. KINECT 3: A phase 3 randomized, double-blind, placebo-controlled trial of valbenazine for tardive dyskinesia. Am J Psychiatry 2017 Mar 21; [e-pub]. 

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