A multicenter, open-label, sequential study comparing preferences for carbidopa-levodopa orally disintegrating tablets and conventional tablets in subjects with Parkinson's disease

Background: Patients with Parkinson's disease (PD) may have difficulty taking their medications for various reasons. In these patients, orally disintegrating tablets (ODTs) can be given without water and may provide greater convenience and ease of use than conventional tablets. Objective: This study compared preferences for ODTs with those of the conventional tablet formulation of the antiparkinsonism combination drug carbidopa-levodopa (C.-L.) in subjects with PD. Methods: Subjects aged ≥18 years with PD controlledusing a stable dosage of C-L were enrolled in this multicenter, open-label, sequential study. Subjects received their stable dose of conventional C-L for 7 ± 3 days. They were then switched to the same dose of C-L in the ODT formulation for 14.± 3 days. During the last 3 days of each treatment period, subjects were to record in a diary their "on" and "off" times (asymptomatic and symptomatic parkinsonism, respectively) and medication use. On the final day of each treatment period, the Unified Parkinson's Disease Rating Scale (UPDRS) was administered to subjects before the first morning dose and then after dosing when they mentioned they were experiencing the "on" state. A Global Preference Questionnaire (GPQ) was completed by subjects at the end of the study. The primary variable was response to all GPQ items. Secondary variables were changes in UPDRS score and mean amount of "off" time per 24 hours. Adverse effects (AEs) also were monitored. Results: Sixty-one subjects (31 men, 30 women; mean[SD] age, 71.8 [8.3] years; mean body weight, 76.2 kg) participated in the study and were included in the AE assessment; 60 completed the study and were included in the efficacy assessment. Twenty-seven subjects (45%) preferred ODTs compared with 12 (20%) who preferred the conventional tablets (P < 0.017). The remaining 21 subjects (35%) had no preference. The attributes of the ODTs that influenced subjects' preference for that formulation included accessibility to medication to treat "off" times (30 [50%]); ease of activities of daily living (28 [47%]); reduced concern about swallowing the medication (27 [45%]); and use for nighttime dosing, ease of compliance with dosing schedule, and feeling less selfconscious about others noticing medication use (each, 25 [42%]) (all, P < 0.001). No statistically significant differences in UPDRS scores in the "on" and "off" states were found between the 2 formulations. The incidence of AEs was statistically similar between the 2 formulations. Conclusions: In this small study of ODT C-L versus conventional C-L tablets in these adult subjects with PD, the results suggest that the ODTs may be of value in certain patients with PD, depending on their personal preferences, disease status, and willingness to alter an aspect of their medication use. For selected patients with PD, the ODT C-L formulation may provide increased convenience, ease of use, and rapid access to medication.