pasireotide and Neuroectodermal-Tumors

Functional gastroenteropancreatic tumors express all 5 somatostatin receptor subtypes (sst) in different quantities. Octreotide and lanreotide treat patients with these tumors by binding preferentially to sst2 and, to a lesser extent, to sst3 and sst5 receptors, thereby controlling prominent symptoms caused by hormone hypersecretion (diarrhea and flushing). Although symptoms initially improve in most patients, a loss of response occurs in about 50% during continuous treatment. The functional activity at sst receptors of SOM230, a new multiligand somatostatin analog, has been described and compared with that of somatostatin (SRIF-14) and octreotide. These data show that SOM230 is a full agonist with nanomolar potency at sst(1,2,3) and sst5 receptors. The multiligand activity profile of SOM230, together with its nondesensitizing inhibitory effect on growth hormone and insulin-like growth factor-I secretion in rats, may underlie its successful use in clinical trials and its potential for use in refractory patients with carcinoid tumors.

Topics: Animals; Antineoplastic Agents, Hormonal; Cell Line, Tumor; Colforsin; Cricetinae; Cricetulus; Cyclic AMP; Dose-Response Relationship, Drug; Drug Interactions; Humans; Neuroectodermal Tumors; Octreotide; Receptors, Somatostatin; Recombinant Proteins; Somatostatin; Transfection