Treatment of the malignant carcinoid syndrome. Evaluation of a long-acting somatostatin analogue.

We studied the effects of a long-acting analogue of somatostatin (SMS 201-995, Sandoz) in 25 patients with histologically proved metastatic carcinoid tumors and the carcinoid syndrome. This drug was self-administered by subcutaneous injection at a dose of 150 micrograms three times daily. Flushing and diarrhea associated with the syndrome were promptly relieved in 22 patients. All 25 patients had an elevated 24-hour urinary excretion of 5-hydroxyindoleacetic acid (5-HIAA) (mean, 265 mg per 24 hours; range, 14 to 1079), which served as an objective indicator of disease activity. Eighteen of the 25 patients (72 percent) had a decrease of 50 percent or more in their urinary 5-HIAA levels, as compared with the pretreatment values. The median duration of this biochemical response was more than 12 months (range, 1 to greater than 18). Since no serious toxicity was observed, we conclude that SMS 201-995 may be appropriate for use as early therapy in patients with symptoms due to the carcinoid syndrome who have not responded to simpler measures.