Once-Daily Valbenazine Is Effective for Tardive Dyskinesia in Elderly Patients (>=65 Years)

Introduction Valbenazine is a selective and potent vesicular monoamine transporter 2 (VMAT2) inhibitor approved for the treatment of tardive dyskinesia (TD), a persistent and potentially disabling movement disorder associated with prolonged exposure to antipsychotics or other dopamine-receptor blocking agents (DRBAs). Valbenazine is the only approved TD medication with once-daily dosing and no requirements or cautions for dosing based on age. Older adults (≥55 years) have an increased risk for TD after a shorter duration of treatment with DRBAs, and previous analyses have shown that valbenazine is effective and well tolerated in this population (Sajatovic et al, Int J Geriatr Psychiatry 2020). The current presentation includes findings from the first analyses to evaluate the effects of an approved TD medication in an elderly population, using the more conventional age cutoff of ≥65 years. Methods Data from two long-term studies (KINECT 3-extension, KINECT 4) of participants receiving up to 48 weeks of once-daily treatment with valbenazine (40 mg or 80 mg) were pooled and analyzed by age (≥65 and <65 years). Analyses included mean change from baseline (CFB) to Week 48 in Abnormal Involuntary Movement Scale (AIMS) total score. AIMS response at Week 48 was also assessed as follows: clinically meaningful response (≥30% improvement from baseline); protocol-defined response (≥50% improvement from baseline). Additional analyses included response thresholds for Clinical Global Improvement-Tardive Dyskinesia (CGI-TD) and Patient Global Impression of Change (PGIC) as follows: rating of “minimally improved” or better (score ≤3) at Week 48 (CGI-TD≤3, PGIC≤3); rating of “much improved” or “very much improved” (score ≤2) at Week 48 (CGI-TD≤2, PGIC≤2). Treatment-emergent adverse events (TEAEs) were also monitored. Results Treatment outcomes were generally robust and comparable between the age subgroups. Pooled AIMS results indicated substantial improvements in TD movements were found in both age subgroups with valbenazine 40 mg (≥65 years, n=8; <65 years, n=46) and 80 mg (≥65 years, n=20; <65 years, n=105): mean CFB (≥65 years, -6.4 and -9.8 [for 40 and 80 mg, respectively]; <65 years, -5.5 and -8.3); clinically meaningful ≥30% response (≥65 years, 75% and 95%; <65 years, 61% and 80%); and protocol-defined ≥50% response (≥65 years, 75% and 85%; <65 years, 50% and 70%). CGI-TD and PGIC response rates indicated that clinician- and patient-reported global improvements were also substantial in both age subgroups: CGI-TD≤3 (≥65 years, 88% and 100% [for 40 and 80 mg, respectively]; <65 years, 89% and 97%); CGI-TD≤2 (≥65 years, 88% and 95%; <65 years, 62% and 83%); PGIC≤3 (≥65 years, 88% and 100%; <65 years, 89% and 94%); PGIC≤2 (≥65 years, 75% and 90%; <65 years, 77% and 80%). Analyses of TEAEs indicated no statistically significant differences between age subgroups for the incidence of any TEAEs (≥65 years, 73%; <65 years, 72%) or any serious TEAEs (≥65 years, 18%; <65 years, 17%). However, discontinuations due to TEAEs were significantly more common in elderly participants (≥65 years, 26%; <65 years, 13%; P<0.05). Conclusions These analyses, which are the first to evaluate any approved TD medication in patients ≥65 years, indicate that long-term treatment with once-daily valbenazine is appropriate and beneficial for this age group. Elderly study participants had clinically meaningful and substantial improvements in TD that were comparable to (or better than) those in the younger cohort. These results may provide clinicians with important information about the management of TD in elderly patients. This research was funded by Neurocrine Biosciences, Inc.