LOS ANGELES—Once-daily treatment with valbenazine for 48 weeks provides substantial improvements on clinician- and patient-reported outcomes in adults with tardive dyskinesia, according to data described at the 70th Annual Meeting of the American Academy of Neurology. The results are consistent with those of previous trials, said the researchers. Valbenazine is well-tolerated and does not raise significant safety concerns.
Valbenazine was approved as a treatment for tardive dyskinesia on the basis of several short-term placebo-controlled trials, a blinded extension study, and the long-term KINECT 4 study. Stewart Factor, DO, Professor of Neurology at Emory University School of Medicine in Atlanta, and colleagues conducted a study to evaluate the long-term effects of once-daily valbenazine on tardive dyskinesia.
Eligible participants were adults with de novo tardive dyskinesia and those who had participated in prior trials of valbenazine. All participants received 48 weeks of open-label treatment with valbenazine. The initial dose was 40 mg. If an investigator judged that a patient had inadequate clinical response at week four, the dose was increased to 80 mg, based on tolerability. For patients who could not tolerate the 80-mg dose, the dose was decreased to 40 mg.
Dr. Factor and colleagues used the change from baseline in the Abnormal Involuntary Movement Scale (AIMS) total score to assess changes in tardive dyskinesia. Other efficacy assessments included the Patient Global Impression of Change (PGIC) and Clinical Global Impression of Change-Tardive Dyskinesia (CGI-TD) scales. The investigators applied standard safety methods, including treatment-emergent adverse event reporting.
The safety population included 163 participants. Of this group, 107 participants received and tolerated the 80-mg dose, 45 did not require escalation from the 40-mg dose, and 11 were escalated to 80-mg dose, but later required reduction to the 40-mg dose. The mean change from baseline to week 48 in AIMS total score indicated improvements in tardive dyskinesia in all dose groups. The 80-mg group had a decrease of 11.0 points, the 40-mg group had a decrease of 10.2 points, and the group whose dose was decreased from 80 mg to 40 mg had a decrease of 7.2 points.
At week 48, more than 75% of participants in each study arm had a PGIC score of 2 or lower (ie, much improved or very much improved). This outcome was achieved in 89.2% of the 80-mg group, 90.0% of the 40-mg group, and 77.8% of the group whose dose was decreased from 80 mg to 40 mg. Mean CGI-TD scores at week 48 were 1.6 for the 80-mg group, 1.7 for the 40-mg group, and 2.3 for the group whose dose was reduced from 80 mg to 40 mg. These scores indicated clinically meaningful long-term improvement for all dose groups.
Less than 15% of all participants had a serious treatment-emergent adverse event (12.9%) or treatment-emergent adverse event leading to discontinuation (14.7%).
The study was funded by Neurocrine Biosciences, the manufacturer of valbenazine.