Real-World Study of ABBV-951 Subcutaneous Infusion to Assess Change in Disease Activity in Adult Participants With Parkinson's Disease

Parkinson's disease (PD) is a neurological condition, which affects the brain. PD gets worse over time, but how quickly it progresses varies a lot from person to person. Some symptoms of PD are tremors, stiffness, and slowness of movement. The purpose of this study is to evaluate how effective ABBV-951 is in treating adult participants with advanced PD in real world setting. ABBV-951 (foslevodopa/foscarbidopa) is an approved drug for the treatment of Parkinson's Disease. The main ROSSINI study will have approximately 450 adult participants with PD (300 participants new to ABBV-951, up to 150 participants transitioning from open-label extension study) will be enrolled across approximately 60 sites. Decision to treat with ABBV-951 (or continue the treatment in Cohort B) will be made by the doctor prior to any decision to approach the participant to participate in this study. There will be a sub-study that will enroll 40 naïve participants who initiated Foslevodopa/Foscarbidopa treatment for the first time (Cohort A of the ROSSINI parent study only) from 6 to 15 centers in the United States, Germany and Spain. All participants will receive subcutaneous infusion of ABBV-951 for approximately 3 years. Participants will attend regular clinic visits during the course of the study. The effect of the treatment will be checked by medical assessments, and completing questionnaires.