Patients taking valbenazine saw persistent improvements in tardive dyskinesia (TD) symptoms for more than a year, researchers found in a long-term open-label study.
The study enrolled 161 people with TD who had completed either the KINECT 3 or KINECT 4 study. In those studies, patients took 40 or 80 mg of valbenazine once a day for up to 48 weeks, followed by 4-week washout period. The subsequent study was primarily designed to further evaluate the long-term safety of valbenazine, a vesicular monoamine transporter-2 (VMAT2) inhibitor.
Following the washout, participants were started on 40 mg/day of valbenazine. After 4 weeks, dosing was increased to 80 mg/day, based on tolerability and clinical assessment of TD symptoms. Reductions to 40 mg/day were allowed for tolerability.
The study was planned for 72 weeks or until valbenazine was commercially available. When it was terminated due to commercial availability of the drug, 85.7% (138 of 161) of participants were still active. Four participants had reached week 60, and none reached week 72.
“Valbenazine was generally well tolerated and no new safety signals were observed,” researchers wrote. “Clinician ratings of TD severity, patient reports of satisfaction with treatment, and a high proportion of retention in the study indicated that participants continued to experience TD improvements and perceived ongoing benefit with once-daily valbenazine throughout the course of this study.”
The study was sponsored by Neurocrine Biosciences, maker of valbenazine (Ingrezza).