Study to Evaluate the Efficacy and Safety of 90Y-SMT487 in Subjects With Symptomatic Malignant Carcinoid Tumors

Inclusion Criteria:

1. Life expectancy \> 6 months.
2. Subjects must have distant metastases.
3. Subjects must be able to discontinue Sandostatin LAR treatment for at least 1 month prior to Day 1/Cycle 1; last dose of Sandostatin LAR must be 60 days or more prior to the first OctreoTher™ dose. For subcutaneous Sandostatin discontinuation should be 12 hours. Subjects taking other long acting somatostatin analogues must discontinue the analogue at least 2 times the dosing interval.
4. Upon baseline disease assessment, all subjects must have at least 1 measurable site of disease that either has never been irradiated or if the measurable lesion has been previously irradiated; this same lesion has since demonstrated progression base don the SWOG response criteria.
5. Subjects must state or agree with the statement that "I have symptoms from my cancer that bother me." Subjects must have failed to gain complete symptom control despite an optimal attempt at somatostatin therapy in the judgement of their physician.

Exclusion Criteria:

1. Chemotherapy, biologic therapy or other investigational therapy within 4 weeks of Day 1.
2. Surgery, hormonal therapy (not including somatostatin analogues) or radiation, within 2 weeks of Day 1.
3. Subjects with know brain metastases unless these metastases have been treated and stabilized for at least six months prior to study start.
4. Subjects who received high dose OctreoScan therapy or other radiolabelled somatostatin therapy or other systemic radiolabelled therapy (e.g. MIBG) for treatment of metastatic carcinoid.