Carcinoid Syndrome Efficacy Study Featuring an Oral Daily Paltusotine Regimen

A Phase 3, randomized, double-blinded, placebo-controlled study to evaluate the efficacy and safety of paltusotine treatment vs placebo as well as the long-term safety of paltusotine in adults with carcinoid syndrome due to well-differentiated neuroendocrine tumors. The purpose of this study is to continue the evaluation of the safety, efficacy, and pharmacokinetics (PK) of paltusotine in participants with carcinoid syndrome.

Inclusion Criteria: * Male or female ≥18 years of age, at the time of Screening. * Willing and able to comply with the study procedures as specified in the protocol, including at least 70% compliance with the study diary for the 2-week period. * Documented carcinoid syndrome requiring medical therapy. Participants must exhibit symptoms of flushing with or without frequent BMs as follows: * For participants who are naïve/not currently treated with somatostatin receptors ligands (SRL), they must exhibit an average of \>1 flushing episode/day over a period of 14 days * For participants who will wash out from SRL treatment, they must be symptomatically controlled and exhibit an increase in daily average flushing episodes and an average of \>1 flushing episode/day over a period of 14 days during the Washout Period. * Evaluable documentation of locally advanced or metastatic histopathologically confirmed well-differentiated neuroendocrine tumor(s) \[NETs\]. * No significant disease progression as assessed by the Investigator within the last 6 months before randomization. Exclusion Criteria: * Diarrhea attributed to any condition(s) other than carcinoid syndrome. * Uncontrolled/severe diarrhea associated with significant volume contraction, dehydration, or hypotension. * Requires second line treatments (eg, telotristat) for control of carcinoid syndrome symptoms in the opinion of the Investigator. * Treatment with specific NET therapy \