Vapreotide (trifluoroacetate salt)

Vapreotide is a peptide neurokinin-1 receptor (NK1) antagonist and analog of somatostatin (IC50 = 330 nM in a radioligand binding assay). It inhibits increases in vascular permeability stimulated by substance P in a concentration-dependent manner in isolated guinea pig trachea and main bronchi. Vapreotide (8 nmol per animal) reduces substance P-induced biting and scratching in mice. It increases reaction time to heat stimuli in the hot plate and tail flick tests when administered at a dose of 512 μg/kg, indicating antinociceptive activity in mice. Vapreotide reduces plasma growth hormone (GH) increases induced by phenobarbital , morphine , and chlorpromazine , hypoglycemia-induced glucagon elevation, and glucose-induced insulin secretion in rats. It also decreases tumor weight and volume in a hamster model of pancreatic ductal adenocarcinoma and suppresses tumor growth and reduces GH secretion in SK-ES-1 and MNNG/HOS osteosarcoma mouse xenograft models.