The somatostatin analogue SMS 201-995 in acromegaly: prolonged, preferential suppression of growth hormone but not pancreatic hormones.

The treatment of acromegaly is not optimal at present, since many patients have continued growth hormone hypersecretion. We report the acute effects of a cyclic octapeptide analogue of somatostatin, SMS 201-995 (Sandoz) in 9 nondiabetic, acromegalic patients between the ages of 30 and 74. We report potent and prolonged dose-dependent effects to suppress growth hormone secretion. A single 50 micrograms dose of SMS 201-995 inhibited growth hormone concentration rapidly within 15 minutes, with maximal effect in 75 minutes. Maximal inhibition was of the order of 80%, with absolute concentrations under 2 micrograms/L for about 6 hours in 5 of 7 patients. Growth hormone concentrations remained significantly suppressed below placebo control for up to 24 hours after a single dose of SMS 201-995, but the inhibitory effects on insulin and C-peptide concentrations were limited to 2 hours. The effects on glucagon secretion were minimal, and also evident for only 2 hours. Mild transient postprandial elevations of plasma glucose and FFA were documented. No adverse effects were noted; routine hematology, biochemistry, and vital signs were not altered. Thus SMS 201-995, with preferential effects at the pituitary somatotroph, holds considerable promise as an attractive and viable alternative for treatment of acromegaly.