Pentetreotide

Summary

In-111 pentetreotide (OctreoScan) is an FDA-approved radiopharmaceutical used for scintigraphic localization of neuroendocrine tumors bearing somatostatin receptors, including carcinoid tumors, gastrinomas, VIPomas, and other gastroenteropancreatic tumors. It enables whole-body imaging to detect primary and metastatic lesions.

Mechanism of Action

Pentetreotide is octreotide conjugated to DTPA (diethylenetriaminepentaacetic acid), which chelates indium-111 (In-111). It binds to somatostatin receptors (SSTR2 and SSTR5) overexpressed on neuroendocrine tumor cells, enabling scintigraphic imaging via gamma camera or SPECT after intravenous administration of In-111 pentetreotide.

Routes of Administration

Goals & Uses

• Staging and metastasis detectionOncology / StagingHigh
• Detection of small cell lung cancerDiagnostic OncologyModerate
• Patient selection for somatostatin analogue therapyTheranosticsModerate
• Localization of neuroendocrine tumorsDiagnostic ImagingHigh
• Pheochromocytoma and paraganglioma localizationDiagnostic ImagingModerate

Contraindications

• PregnancyPopulationHighPotential fetal risk or insufficient safety data
• BreastfeedingPopulationModeratePotential transfer into breast milk or insufficient safety data
• Hypersensitivity to octreotide or DTPAAllergyHigh

Adverse Effects

• Radiation exposureRadiologicalCommon
• Anaphylaxis / hypersensitivity reactionImmunologicRare
• FlushingVascularUncommonWarmth and redness of the skin
• NauseaGastrointestinalUncommonFeeling of sickness or urge to vomit
• Hypoglycemia or hyperglycemiaMetabolicRare
• DiarrheaGastrointestinalUncommonLoose or frequent stools

Drug Interactions

• Octreotide (therapeutic)High
• LanreotideHigh
• Total parenteral nutrition (TPN)Low

Population Constraints

• Renal impairmentOrgan ImpairmentRelative
• Pediatric patientsAgeRelative
• Patients with insulinomaEndocrineRelative

Regulatory Status

• European UnionApprovedApproved: Diagnostic imaging of neuroendocrine tumors expressing somatostatin receptorsApproved in EU member states; use has declined significantly with availability of Ga-68-labeled analogues offering superior PET imaging.
• United StatesApprovedApproved: Scintigraphic localization of primary and metastatic neuroendocrine tumors bearing somatostatin receptors, Carcinoid tumors, Gastrinomas and other gastroenteropancreatic tumorsApproved by FDA in 1994 as OctreoScan (Mallinckrodt/Curium). Still commercially available but increasingly displaced by Ga-68 DOTATATE (Netspot) in clinical practice.
• United KingdomApprovedApproved: Somatostatin receptor scintigraphy for neuroendocrine tumor detectionAvailable in UK; NHS practice increasingly favors Ga-68 DOTATATE PET-CT per NICE guidance.

Approved by the FDA in 1994 under the brand name OctreoScan. Classified as a diagnostic radiopharmaceutical. Requires nuclear medicine facility and radiation safety protocols. Largely being replaced in clinical practice by Ga-68-labeled somatostatin analogues (e.g., Ga-68 DOTATATE) due to superior sensitivity, though still approved and in use.

Evidence & Sources

No sources recorded yet.