PREPARED: Comparison of prolonged and immediate release ropinirole in advanced Parkinson's disease

Background: PREPARED was a randomized, parallel‐group, double‐blind, multicenter study to evaluate the efficacy of adjunctive ropinirole prolonged release (PR) versus immediate release (IR) in patients with advanced Parkinson's disease (PD). Methods: Patients received once‐daily PR (2–24 mg/d; n = 177) or three‐times‐daily IR (0.75–24 mg/d; n = 173) for 24 weeks. The primary endpoint was the proportion of patients maintaining ≥20% reduction from baseline in “off” time over two consecutive visits at Week 24 last observation carried forward (LOCF). Results: At Week 24 LOCF, PR significantly increased the proportion of patients maintaining ≥20% reduction in “off” time versus IR (adjusted odds ratio: 1.82; 95% CI: 1.16, 2.86; P = 0.009). Mean (SD) doses at Week 24 LOCF were: PR, 18.6 (6.5) mg/d; IR, 10.4 (6.4) mg/d; mean (SD) reductions from baseline in levodopa ( L ‐dopa) dose were –162 (226) mg and –113 (138) mg, respectively. Adverse events (AEs) were reported by 72% of patients in the PR group and 61% in the IR group; 12% and 9% of patients, respectively, withdrew from the study due to an AE, and 6% and 5%, respectively, reported serious AEs. Conclusions: Adjunctive PR provided a significantly greater improvement in symptom control in terms of the odds of achieving ≥20% maintained reduction in time spent “off” compared with IR. Interpretation may be confounded by the higher doses of PR versus IR that were achieved, in combination with lower doses of L ‐dopa by the study end. Despite dosing differences, the PR titration regimen was generally well tolerated, with an AE profile similar to that of IR. © 2011 Movement Disorder Society