Sustained Treatment Response with Long-Term Valbenazine in Patients with Tardive Dyskinesia
Christoph Correll1, Jean-Pierre Lindenmayer2, Khody Farahmand3, Eric Jen3, Scott Siegert3, Eduardo Dunayevich3
1The Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, 2Nathan Kline Institute for Psychiatric Research at Manhattan Psychiatric Center, 3Neurocrine Biosciences, Inc.
Objective:
To assess patterns of treatment response in patients with tardive dyskinesia (TD) who received once-daily valbenazine in a 48-week clinical trial (KINECT 4 [NCT02405091]).
Background:
Valbenazine is a highly selective vesicular monoamine transporter 2 (VMAT2) inhibitor approved for the treatment of TD, a persistent and potentially disabling movement disorder associated with prolonged exposure to antipsychotics and other dopamine receptor blocking agents. 
Design/Methods:

Data from KINECT 4 treatment completers (participants who reached the Week 48 visit) were analyzed post hoc. Analyses were conducted at Week 8 (first study visit after dose-optimization period) and Week 48 (end of treatment) using the following thresholds: ≥50% and ≥70% improvement from baseline in Abnormal Involuntary Movement Scale (AIMS) total score; rating of “much improved” or “very much improved” (score ≤2) on Clinical Global Impression of Change-Tardive Dyskinesia (CGI-TD) and Patient Global Impression of Change (PGIC).

Results:

Of 167 participants in KINECT 4, 103 (62%) were treatment completers and included for analysis. The proportion of these participants who met AIMS response thresholds at Weeks 8 and 48, respectively, were as follows: ≥50% improvement (39% and 86%); ≥70% improvement (17% and 52%). Of 40 participants with AIMS ≥50% improvement at Week 8, 95% also met this threshold at Week 48 (“sustained response”). Of 63 participants with <50% AIMS improvement at Week 8, 81% achieved the ≥50% response threshold at Week 48. The proportion of participants meeting thresholds for global response increased from Week 8 to Week 48 for CGI-TD (from 50% to 92%) and PGIC (from 53% to 88%).

Conclusions:

Post hoc analyses of KINECT 4 data showed that the proportion of participants meeting rigorous treatment response thresholds increased over time. After 48 weeks of treatment with once-daily valbenazine, >80% of participants demonstrated robust improvements in TD, as assessed using the AIMS (≥50% improvement), CGI-TD (score ≤2), and PGIC (score ≤2).

10.1212/WNL.0000000000202243