Impact of valbenazine on physical, psychological, and functional health in 127 patients with tardive dyskinesia: results of EQ-5D-5L health state scores from a double-blind, placebo-controlled, randomized withdrawal phase 4 study
Introduction: Tardive dyskinesia (TD) is a movement disorder associated with prolonged exposure to dopamine receptor blocking agents that can significantly impact one’s quality of life (QoL). A phase 4 study (NCT03891862) assessed persistence of effects of valbenazine (VBZ), a vesicular monoamine transporter 2 inhibitor approved for treatment of TD.
Methods: Patients received open-label VBZ 40mg or 80mg for 8 weeks and were randomized to continue the same dose of VBZ or receive placebo for 8 weeks. A 4-week washout period followed. Analyses were conducted for any patient who received VBZ during the study with available EQ-5D-5L data from baseline (BL) to week 20. The EQ-5D-5L includes 5 dimensions of health status (mobility, self-care, usual activities, pain/discomfort, and anxiety/depression) each scored as: no problems (1); slight problems (2); moderate problems (3); severe problems (4); unable to/extreme problems (5). A utility index (UI) (range: 0-1) and visual analog scale (VAS) (range: 0-100) can also be reported.
Results: At BL (n=127), mean scores were 1.91 for mobility, 1.69 for self-care, 1.98 for usual activities, 2.15 for pain/discomfort, and 2.03 for anxiety/depression, indicating slight problems; mean VAS and UI scores were 73.82 and 0.68, respectively. At week 16 (end of treatment) (n=56), scores for each dimension (1.57,1.34,1.59, 1.70, 1.80, respectively), VAS (79.57), and UI (0.80) significantly improved (all P < 0.05). At week 20 (end of washout; n=55), scores returned to/near BL.
Conclusions: VBZ improved physical, psychological, and functional health, indicated by significant improvements in EQ-5D-5L dimension scores. QoL returned to/near BL following VBZ discontinuation.
