Abstract
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Introduction
Tardive dyskinesia (TD) is a persistent and potentially disabling movement disorder associated with exposure to antipsychotics and other dopamine receptor blocking agents. Effective and comprehensive treatment of TD requires reducing patients’ abnormal involuntary movements without disrupting their psychiatric stability. This can be especially challenging when patients have complex psychiatric conditions (e.g., >1 psychiatric diagnosis) and are taking multiple medications. Valbenazine, a highly potent and selective vesicular monoamine transporter 2 (VMAT2) inhibitor, is approved for the once-daily treatment of TD. This post hoc analysis of two long-term studies (KINECT 3, KINECT 4) was conducted to evaluate changes in psychiatric status and clinician- and patient-reported treatment success in study participants who received valbenazine (40 or 80 mg) for 48 weeks.
Methods
Data from KINECT 3 and KINECT 4 were pooled and analyzed in participants categorized by their primary psychiatric diagnosis: schizophrenia/schizoaffective disorder (“SCHZ”) or mood disorder (“MD”). Concomitant medications needed for managing these and other psychiatric or medical conditions were allowed. Treatment success was defined as achieving a rating of “much improved” or “very much improved” at Week 48, as assessed using the Clinical Global Impression of Change-Tardive Dyskinesia (CGI-TD) and Patient Global Impression of Change (PGIC). Psychiatric stability was monitored using the following scales: Positive and Negative Syndrome Scale (PANSS) and Calgary Depression Scale for Schizophrenia (CDSS) in the SCHZ subgroup; Young Mania Rating Scale (YMRS) and Montgomery-Åsberg Depression Rating Scale (MADRS) in the MD subgroup. Suicidal ideation/behavior was monitored using the Columbia-Suicide Severity Rating Scale.
Results
More than 75% of study participants in the SCHZ subgroup achieved treatment success with valbenazine, based on clinician assessment (CGI-TD, 79.7%) and patient self-report (PGIC, 78.0%). Mean changes from baseline to Week 48 for PANSS scores (positive symptoms [-0.7], negative symptoms [‑0.6], general psychopathology [-1.9], total [-3.2]) and CDSS total score (-0.5) indicated maintenance of psychiatric stability in the SCHZ subgroup. Similar treatment success rates were found in the MD subgroup for both CGI-TD (77.6%) and PGIC (84.5%), with mean changes from baseline in YMRS total score (-1.0) and MADRS total score (+0.3) indicating psychiatric stability was maintained. No emergence of suicidal ideation/behavior was observed during the studies.
Conclusions
Pooled analyses from two 48-week studies indicate that long-term treatment of TD with once-daily valbenazine resulted in substantial clinician- and patient-reported global improvements in TD, while psychiatric stability was maintained regardless of primary psychiatric condition.
Funding
Neurocrine Biosciences, Inc.
