Potential utility of amantadine DR/ER in persons with Parkinson’s disease meeting 5-2-1 criteria for device aided therapy

BACKGROUND: The 5-2-1 criteria (≥5 levodopa doses/day, ≥2 h OFF/day, and ≥ 1-hour dyskinesia/day) propose to identify people with Parkinson’s disease (PD) who are poorly controlled on oral therapies and who may therefore benefit from device-aided therapies. Amantadine-DR/ER is the only medication FDA-approved for both dyskinesia and OFF episodes in levodopa-treated patients. In this post-hoc analysis of phase 3 clinical trials, we evaluated the efficacy and safety of amantadine-DR/ER in patients meeting 5-2-1 criteria. METHODS: Week-12 treatment differences (Amantadine-DR/ER − placebo) in the Unified Dyskinesia Rating Scale (UDysRS) and PD motor states (patient diaries) were evaluated in pooled, phase-3, double-blind trial participants meeting 5-2-1 criteria at baseline. This 5-2-1 cohort was followed into a 2-year open-label trial, where Movement Disorder Society - Unified Parkinson’s Disease Rate Scale (MDS-UPDRS) Part IV scores were assessed relative to double-blind baseline. RESULTS: Of 198 enrolled participants in the phase 3 trials, 65 (33%; n = 29 placebo; n = 36 amantadine-DR/ER) comprised the 5-2-1 cohort. At Week-12 endpoint, amantadine-DR/ER significantly improved UDysRS scores (treatment difference of 9.57 ± 3.15 points, p = 0.004) and ON time without troublesome dyskinesia (‘good ON’, treatment difference of 2.9 ± 0.90 h/day, p = 0.002). Improvements in good ON time resulted from significant reductions in both troublesome dyskinesia and OFF time. Treatment benefit on MDS-UPDRS-Part IV was sustained through open-label, follow-up. The most common adverse events in patients who met 5-2-1 criteria and were treated with amantadine-DR/ER included falls and peripheral edema. CONCLUSIONS: Findings suggest Amantadine-DR/ER should be considered as an option for people with PD who meet 5-2-1 criteria.