Inclusion Criteria:

- Males and females, aged 18 and older

- Biopsy-proven metastatic carcinoid tumor of the GI tract with disease extent
confirmed by CT, MRI, or radionuclide imaging

- Symptoms not managed by stable-dose long-acting octreotide therapy (≥4 bowel
movements per day)

- Ability to provide written informed consent

Exclusion Criteria:

- ≥12 high volume, watery bowel movements per day

- Sponsor-unacceptable clinical laboratory values for hematology and liver function
tests at screening

- Karnofsky status ≤70% - unable to care for self

- Surgery within 60 days prior to screening

- A history of short bowel syndrome

- Life expectancy <12 months

- History of substance or alcohol abuse within 2 years prior to screening

- Previous exposure to a tryptophan hydroxylase (TPH) inhibitor

- Administration of any investigational drug within 30 days of screening or any
therapeutic protein or antibody within 90 days of screening