**Carcinoid Syndrome Study** This study is testing a new pill, paltusotine, to see how well it works for people with carcinoid syndrome, a condition caused by a type of cancer called neuroendocrine tumors (NETs). The study is split into different parts: screening (up to 11 weeks), testing (16 weeks), and a longer-term part where everyone tries the real pill (104 weeks), plus a 4-week follow-up. "Randomized" means participants are picked by chance to get either the real pill or a fake one (placebo) at first. **Key Points:** - **Time Commitment:** The study lasts several months, with a total of 135 weeks including screening, treatment, and follow-up. - **Eligibility:** Participants must be over 18, have carcinoid syndrome symptoms, and be able to follow study rules. - **Risks:** You cannot join if you have severe diarrhea not related to carcinoid syndrome or other serious health problems. **Note:** To join, you must have had no major surgeries recently and need to stop certain cancer treatments before starting.