Study S187.3.003 (NCT00360568) is a Phase 3, 12-month, open-label, multicenter continuation treatment study of the safety, tolerability, and efficacy of levodopa-carbidopa intestinal gel (LCIG) in the treatment of participants with levodopa-responsive Parkinson's disease (PD) with persistent motor fluctuations despite optimized treatment with available PD medications. All participants received LCIG.