99mTc-HYNIC (Tyr3)-octreotide

Summary

99mTc-HYNIC-(Tyr3)-octreotide (also known as Tektrotyd or depreotide-related agent; commercially Tektrotyd in some markets) is a technetium-99m–labeled somatostatin analogue used for scintigraphic detection of neuroendocrine tumors and other somatostatin receptor–positive lesions. The HYNIC chelator links Tc-99m to the (Tyr3)-octreotide peptide backbone, providing favorable pharmacokinetics and high image quality compared to earlier In-111 pentetreotide.

Mechanism of Action

Binds with high affinity to somatostatin receptors (primarily SSTR2 and SSTR5) expressed on neuroendocrine tumor cells; the technetium-99m radiolabel enables gamma scintigraphy or SPECT imaging of receptor-expressing tissues.

Routes of Administration

Goals & Uses

• Detection of meningiomasDiagnostic OncologyModerate
• Staging and restaging of NETsDiagnostic OncologyHigh
• Detection of neuroendocrine tumors (NETs)Diagnostic OncologyHigh
• Detection of small cell lung cancerDiagnostic OncologyModerate
• Assessment of somatostatin receptor expression prior to PRRTTreatment PlanningModerate

Contraindications

• Hypersensitivity to octreotide or somatostatin analoguesAllergyHigh
• Severe renal impairmentOrganModerateKidney function concerns
• PregnancyPopulationHighPotential fetal risk or insufficient safety data
• BreastfeedingPopulationModeratePotential transfer into breast milk or insufficient safety data

Adverse Effects

• Radiation exposureRadiologicalCommon
• Hypersensitivity / anaphylaxisImmunologicalRare
• Injection site reactionsLocalUncommon
• NauseaGastrointestinalUncommonFeeling of sickness or urge to vomit
• Hypoglycemia or hyperglycemiaMetabolicRare

Drug Interactions

• GlucocorticoidsLow
• Insulin and antidiabetic agentsLow
• Long-acting somatostatin analogues (octreotide LAR, lanreotide)High

Population Constraints

• Patients on long-acting somatostatin analoguesPharmacologicalRelative
• Pediatric patientsAgeRelative
• Breastfeeding womenReproductiveRelative
• Pregnant womenReproductiveAbsolute
• Patients with severe renal impairmentOrgan ImpairmentRelative

Regulatory Status

• European UnionApprovedApproved: Scintigraphic localization of somatostatin receptor–positive tumors including neuroendocrine tumorsApproved in several EU member states (e.g., Poland) under the brand name Tektrotyd. Not centrally approved by EMA as a single product; availability varies by country.
• United StatesUnapprovedNot FDA-approved. The US market uses In-111 pentetreotide (OctreoScan, now largely replaced) and Ga-68 DOTATATE (Netspot) or Ga-68 DOTATOC for somatostatin receptor imaging.
• United KingdomUnknownNo specific MHRA approval identified post-Brexit; Ga-68–labeled agents are preferred in UK clinical practice.

Approved in several European countries and other jurisdictions (e.g., Poland under the brand Tektrotyd) for SPECT imaging of somatostatin receptor–positive tumors. Not FDA-approved in the United States; In-111 pentetreotide (OctreoScan) historically held that role and has been largely superseded by Ga-68 DOTATATE PET in the US and EU.

Evidence & Sources

No sources recorded yet.