Parkinson's Disease (PD) is a brain disorder that worsens over time and can cause tremors, stiffness, and slow movements. This study in Belgium aims to see how well a drug called Foslevodopa/Foscarbidopa helps adults with advanced PD. This drug is already approved for PD treatment. Around 120 adults will be part of this study across 15 sites in Belgium. They will receive the drug through a tube under the skin, as their doctor prescribes. The study will last up to 18 months, but participants will just follow their usual hospital or clinic visits, so there's no extra burden.