This clinical trial is to study **suvecaltamide**, a new medication to help with tremors in adults with Parkinson's disease (PD). Tremors are shaky movements that can make everyday tasks hard to do. The study lasts up to **23 weeks**. Here’s how it works: 1. **Screening Period:** First, there’s a 4-week screening to check eligibility. 2. **Treatment Period:** Participants will either get suvecaltamide or a placebo (a "fake" pill) for 17 weeks. 3. **Follow-Up:** There's a 2-week follow-up to ensure safety. **Key Points:** - **Study Duration:** Maximum of 23 weeks per participant. - **Eligibility:** Must have moderate to severe tremors not controlled by current PD meds. Must be on stable medication for at least 6 weeks before joining. - **Exclusions:** Pregnant women, those with certain medical conditions or who use recreational drugs, and those planning certain surgeries can't participate. This study is important for finding new ways to help people with PD manage their tremors better.