Octreotide

Mechanism (as reported)

A study review reported octreotide acts as a somatostatin analogue with inhibitory effects on release of anterior pituitary growth hormone and thyroid-stimulating hormone and on peptides of the gastroenteropancreatic endocrine system; it also is described as overcoming some shortcomings of exogenously administered somatostatin (short duration, need for intravenous administration, and rebound hypersecretion). (PMID: 2689136)

Key findings (each cites a source)

• A review reported octreotide is a somatostatin analogue that inhibits release of anterior pituitary growth hormone and thyroid-stimulating hormone and peptides of the gastroenteropancreatic endocrine system, and was described as overcoming some shortcomings of exogenously administered somatostatin (short duration of action, need for intravenous administration, and postinfusion rebound hypersecretion). [PMID 2689136]
• The same review reported clinical studies showing octreotide as effective in the treatment of acromegaly and thyrotrophinomas, and reported comparative trial findings where octreotide was significantly superior to bromocriptine in acromegaly. [PMID 2689136]
• A review reported octreotide as offering a significant advantage in the management of the carcinoid syndrome and considered it to have therapeutic potential for reversing carcinoid crises that may be life-threatening; it also reported trial findings in tumors producing vasoactive intestinal peptide (VIP) suggesting octreotide may be effective as a first-line choice for this condition. [PMID 2689136]
• A review reported limited studies where octreotide was shown to reduce stool/fistula output in high-output secretory diarrhoea (including cryptosporidium-related diarrhoea in AIDS) and in patients with small bowel fistulas, and stated that more well-designed clinical trials are needed to confirm long-term usefulness in these disorders. [PMID 2689136]
• A review described octreotide as being among vasoactive peptides used for portal-hypertension complications of cirrhosis (acute variceal hemorrhage and hepatorenal syndrome), and stated that early initiation of vasoactive peptides was associated with improved outcomes in acute variceal hemorrhage and hepatorenal syndrome. [PMID 31815783]
• A review described that somatostatin receptor imaging using radiolabeled octreotide derivatives (e.g., [(111)In-DTPA0]octreotide) has potential for helping visualize whether somatostatin receptor-positive tumors have recurred, and it described subsequent development of peptide receptor radionuclide therapy using radiolabeled octreotide derivatives (e.g., 90Y- and (111)In-labeled octreotide). [PMID 11038002]
• A randomized clinical trial (PREFIPS) reported that in 651 randomized patients, grade B/C postoperative pancreatic fistula developed in 24.1% (somatostatin arm) versus 22.9% (octreotide arm) with no statistically significant difference reported, and stated that continuous intravenous somatostatin was not statistically different from subcutaneous octreotide in prevention of grade B/C POPF after pancreatectomy. [PMID 38662619]
• A study reported a cleavable doxorubicin-octreotide conjugate designed to target somatostatin receptors on tumor cells, with tumor targeting ability and suppression of adrenocorticotropic hormone secretion in AtT-20 cells assessed via radioimmunoassay; it also reported effective drug release in the presence of a physiological reducing agent and demonstrated relevance in cytotoxicity assays with pituitary, pancreatic, and breast cancer cell lines. [PMID 26524088]
• A review stated that peptide receptor radionuclide therapy (PRRT) involves administering a radiolabeled octreotide derivative targeting somatostatin receptors on neuroendocrine tumor cells, described that 177Lu-peptides represent the predominant form of treatment currently, and stated that PRRT results in significant tumor and symptomatic control in patients with responses described as relatively short-lived. [PMID 40199623]
• The PRRT-focused review described proposed strategies including individualizing treatments based on dosimetric estimates for tumor and normal organs and determining tissue radiosensitivity, and noted that several new peptides and approaches to improve efficacy and tolerability have been proposed. [PMID 40199623]