Immediate versus delayed switch from levodopa/carbidopa to levodopa/carbidopa/entacapone: effects on motor function and quality of life in patients with Parkinson's disease with end-of-dose wearing off.

Objective: Assess motor function and quality of life (QoL) in Parkinson's disease (PD) subjects with end-of-dose wearing off (EODWO), comparing immediate and delayed switch (IS, DEL) to levodopa/carbidopa/entacapone (LCE).
Background: LCE treatment improves motor function in PD patients with EODWO. Correlations with QoL have not been previously assessed.
Methods: A 16-week, prospective, randomized, multicenter, open-label study in PD subjects on stable levodopa/carbidopa (LC) doses with EODWO. The IS subjects switched to LCE at baseline; DEL subjects at week 4. The primary efficacy variable was UPDRS III score (baseline to week 4). QoL measurements (PDQUALIF, PDQ-39) were assessed at baseline, weeks 4, 8, and study endpoint.
Results: The intent-to-treat population comprised 350/359 patients (IS, n = 177; DEL, n = 173). A significant decrease in UPDRS III scores at week 4 was observed (IS, 3.7U, p < .0001; DEL, 1.8U, p = .0018). Group differences favored IS (1.9U, p = .0148). At week 8, IS subjects had significant total score decreases in PDQUALIF (2.5U, p = .0133) and PDQ-39 (5.8U, p = .0001). In the mobility and activities of daily living PDQ-39 subdomains, IS subjects had significantly larger week 4 decreases (versus DEL p = .0331 and p = .0125, respectively). Adverse events included diarrhea (14.5%), nausea (12.3%), and dizziness (8.4%).
Conclusion: The IS provided greater motor improvement at week 4 and improved QoL at week 8.