Improvements Over Time with Valbenazine in Elderly Adults (≥65 Years) with Tardive Dyskinesia: Post Hoc Analyses of 2 Long-Term Studies

Abstract

Objective: To evaluate the long-term effects of once-daily valbenazine (40 or 80 mg) on tardive dyskinesia (TD) in elderly adults (age ≥65 years).

Methods: Data were pooled from two 48-week studies, KINECT 3 extension (NCT02274558) and KINECT 4 (NCT02405091), with analyses performed over time in elderly participants (≥65 years) and at Week 48 by age group (<65 and ≥65 years). Outcomes included mean change in Abnormal Involuntary Movement Scale (AIMS) total score, AIMS response thresholds (≥30% and ≥50% improvement from baseline), and response threshold for Clinical Global Impression of Change-TD (CGI-TD) and Patient Global Impression of Change (PGIC), defined as a score ≤2 ("much improved" or "very much improved"). Safety assessments included treatment-emergent adverse events (TEAEs) and psychiatric symptom scales (eg, Positive and Negative Syndrome Scale).

Results: Of the pooled analysis population (N = 304), 55 (18.1%) were ≥65 years of age. The mean change from baseline in AIMS total score (±standard error) in the ≥65-year age group increased from Week 8 (-4.5 ± 0.7; first visit after dose escalation in KINECT 4) through Week 48 (-8.8 ± 0.9). These robust and sustained improvements were consistent with the percentage who met response thresholds at Weeks 8, 24, and 48: AIMS ≥30% improvement (58.0%, 88.5%, and 89.3%); AIMS ≥50% improvement (40.0%, 65.4%, and 82.1%); CGI-TD score ≤2 (33.3%, 88.5%, and 92.9%); and PGIC score ≤2 (43.1%, 84.6%, and 85.7%). The most common TEAEs among elderly participants were urinary tract infections (10.9%) and somnolence (10.9%). Psychiatric status remained stable during the studies.

Conclusion: Valbenazine was safe and effective in elderly adults who received up to 48 weeks of treatment. Long-term treatment led to substantial and sustained TD improvements per clinician assessment (AIMS, CGI-TD) and patient report (PGIC), with no impact on psychiatric stability.