Objective: To examine long-term outcomes in adults with tardive dyskinesia (TD) who received once-daily valbenazine (VBZ) 40 mg or had a dose reduction from 80 to 40 mg.

Background: Although the 6-wk phase 3 pivotal study, KINECT 3 (K3), only required significance for VBZ 80 mg vs. placebo for the primary endpoint, a 40 mg dose was also assessed. VBZ 40 mg was also included in the K3 extension study in which participants received up to 42 additional wks of VBZ prior to discontinuation (4 wks). VBZ 40 mg was separately assessed in the phase 3 KINECT 4 (K4) study, which included 48 wks of open-label treatment followed by discontinuation (4 wks). Completers from K3 extension or K4 were invited to participate in a rollover study (1506) for additional treatment (up to 72 wks or until commercial availability of VBZ). Few participants reached Wk60 (n=4) or Wk72 (n=0) in 1506 before termination.

Method: Analyses focused on VBZ 40 mg in two pooled populations: K3/K4 (participants who received VBZ 40 mg throughout K3 or K4 or who had a dose reduction [80/40 mg] during K3 or K4); and K3/K4/1506 (participants who received VBZ 40 mg from beginning of K3 or K4 to last visit in 1506 or who had a dose reduction [80/40 mg] at any time). Outcomes for both populations included mean change from baseline (CFB) in AIMS total score (sum of items 1-7) and AIMS response (≥50% total score improvement from baseline) at Wk48 of K3 or K4. Outcomes for the K3/K4/1506 included a Clinical Global Impression of Severity-Tardive Dyskinesia (CGIS-TD) score of 1 (“normal/not at all ill”) or 2 (“borderline ill”) at the last available visit of 1506.

Results: AIMS CFB at Wk48 indicated mean TD improvements in K3/K4 (40 mg, -5.7 [n=54]; 80/40 mg, -6.2 [n=13]) and K3/K4/1506 (40 mg, -9.5 [n=11]; 80/40 mg, -5.6 [n=14]). A majority in both populations had an AIMS response at Wk48: K3/K4 (40 mg, 53.7%; 80/40 mg, 53.8%); K3/K4/1506 (40 mg, 81.8%; 80/40 mg, 50.0%). For CGIS-TD in 1506, no one in the 40 mg group of K3/K4/1506 reached Wk48 (primarily due to VBZ availability). However, at Wks12 (n=11), 24 (n=6), and 36 (n=2), ≥50% of the 40 mg group had a CGIS-TD score ≤2. In the 80/40 mg group at Wk48 of 1506 (n=4), 25.0% had a CGIS-TD score ≤2.

Conclusion: Based on these analyses and results from published studies, VBZ 40 mg may be an effective long-term option for some TD patients. Dose reductions from 80 to 40 mg, if necessary, did not appear to compromise long-term benefit.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/long-term-outcomes-with-valbenazine-40-mg-day-in-adults-with-tardive-dyskinesia/