Once-daily valbenazine was effective and generally well tolerated in adults with tardive dyskinesia who took the drug for up to 48 weeks, according to a study published online in The Journal of Clinical Psychiatry.
“Results indicated that many participants had sustained tardive dyskinesia improvements during long-term treatment,” researchers wrote, “with some return toward baseline severity after valbenazine was discontinued.”
The results stem from a 42-week extension of the 6-week KINECT 3 study, which helped lead to US Food and Drug Administration approval of valbenazine for patients with moderate-to-severe tardive dyskinesia earlier this year. That double-blind trial compared 40-mg and 80-mg doses of valbenazine with placebo and found a significant drop in tardive dyskinesia symptoms with valbenazine, compared with placebo.
At the end of the study, participants were eligible to enter a study extension period to investigate the drug’s long-term impact. Those assigned to placebo during the initial 6-week trial were randomized to either the 40-mg and 80-mg dose of valbenazine over 42 weeks for the extension period. A 4-week washout period followed.
Of 198 adults enrolled in the extension period, 62.6% completed treatment. During the extension period, 69.2% of participants had 1 or more treatment-emergent adverse events, 14.6% had a serious adverse event, and 15.7% discontinued treatment because of an adverse event, researchers reported.
Improvement in tardive dyskinesia symptoms held throughout the extension period. Furthermore, participants tended to remain psychiatrically stable with ongoing valbenazine, with no apparent risk of suicidal ideation or behavior linked with the medication.
During the 4-week washout period, scores on the Abnormal Involuntary Movement Scale and Clinical Global Impression of Change-Tardive Dyskinesia returned toward pretreatment levels.
“This is the first study to report the safety and effectiveness of long-term valbenazine treatment in tardive dyskinesia,” researchers wrote. “Results of this extension study generally indicated that valbenazine was safe and well tolerated, and maintenance of treatment effect was apparent for both doses.”
The study was sponsored by Neurocrine Biosciences, maker of valbenazine (Ingrezza).
Factor SA, Remington G, Comella CL, et al. The effects of valbenazine in participants with tardive dyskinesia: results of the 1-year KINECT 3 extension study. The Journal of Clinical Psychiatry. 2017 November 14;[Epub ahead of print].