Objective: To evaluate the non-inferiority of pramipexole extended-release (ER) versus immediate-release (IR) in Chinese patients with Parkinson's disease (PD) in a double-blind, randomized, parallel-group study.
Methods: Subjects were Chinese patients with idiopathic PD with diagnosis ≥ 2 years prior to trial, age ≥ 30 years old at diagnosis, and Modified Hoehn and Yahr score 2-4 during 'on'-time. Subjects received treatment with pramipexole ER (n=234) or IR (n=239). Non-inferiority was based on the primary endpoint, the change from baseline to end of maintenance (week 18) in the UPDRS (Parts II + III) total score.
Results: For the primary endpoint, the adjusted mean changes (standard error) of UPDRS Parts II + III at week 18 were -13.81 (0.655) and -13.05 (0.643) for ER and IR formulations, respectively, using ANCOVA adjusted for treatment and centre (fixed effect) and baseline (covariate). The adjusted mean between group difference was 0.8 for the 2-sided 95% CI (-1.047, 2.566). Since the lower limit of the 2-sided 95% CI (-1.047) for treatment difference was higher than the non-inferiority margin of -4, non-inferiority between pramipexole ER and IR was demonstrated. The incidence of adverse events (AEs) was 68.8% in the ER arm and 73.6% in the IR arm with few severe AEs (ER: 2.1%; IR: 3.8%).
Conclusion: Based on the UPDRS II + III score, pramipexole ER was non-inferior to pramipexole IR. The safety profiles of pramipexole ER and IR were similar. These results were based on comparable mean daily doses and durations of treatment for both formulations.
Keywords: Non-inferiority; Parkinson’s disease; Pramipexole ER; Pramipexole IR; Safety; Unified Parkinson’s Disease Rating Scale (UPDRS).