This study is testing **DSP-1083**, a special treatment for people with Parkinson's disease (PD). Parkinson's disease is a condition that affects movement, causing symptoms like tremors and stiffness. The study is being conducted in 5-8 locations across the United States. DSP-1083 involves the use of *dopaminergic progenitor cells*, which are cells that can become dopamine-producing brain cells. Dopamine is a brain chemical that helps control movement. The study will see if this new treatment is safe and how well it works. Participants will either receive the actual treatment or a sham surgery (a procedure that looks like surgery but doesn't involve the treatment). The study lasts for 104 weeks, which is about two years. Participants will have to undergo surgery and routine checks to see how their body responds. **Key Points:** - The study lasts 104 weeks and requires surgery. - Participants must be diagnosed with Parkinson's disease and meet certain health criteria. - Safety will be monitored closely through regular tests and visits. If you are interested, it's important to understand the commitment and risks involved before deciding to participate.