Minigastrin

Summary

Minigastrin is a truncated synthetic analogue of gastrin designed primarily as a radiolabeled peptide for targeted tumor imaging and therapy. It consists of the C-terminal sequence of gastrin with high CCK-BR affinity. Multiple radiolabeled variants (e.g., DOTA-MGS5, CP04) have been investigated for PRRT of medullary thyroid carcinoma and other CCK-BR-overexpressing tumors. It is not approved for clinical use and remains under clinical and preclinical investigation.

Mechanism of Action

Binds with high affinity to cholecystokinin-B/gastrin receptors (CCK-BR), which are overexpressed on various tumor cells (e.g., medullary thyroid carcinoma, small cell lung cancer). When radiolabeled, minigastrin delivers targeted radiation to CCK-BR-expressing tumors via peptide receptor radionuclide therapy (PRRT).

Routes of Administration

Goals & Uses

• Tumor imaging / nuclear medicine diagnosticsDiagnostic ImagingModerate
• Targeted radionuclide therapy of medullary thyroid carcinomaOncology / PRRTModerate
• Small cell lung cancer targetingOncologyLow
• Therapy of gastroenteropancreatic neuroendocrine tumorsOncology / PRRTLow

Contraindications

• Bone marrow insufficiencyHematologicalModerate
• Severe renal impairmentOrganHighKidney function concerns
• PregnancyPopulationHighPotential fetal risk or insufficient safety data
• BreastfeedingPopulationHighPotential transfer into breast milk or insufficient safety data

Adverse Effects

• Injection site reactionsLocalUncommon
• Radiation-induced secondary malignancyOncologicRare
• Nausea and vomitingGastrointestinalCommon
• MyelosuppressionHematologicUncommon
• NephrotoxicityRenalUncommon

Drug Interactions

• Proton pump inhibitors / H2-receptor antagonistsLow
• Nephrotoxic agents (e.g., aminoglycosides, cisplatin, NSAIDs)High

Population Constraints

• Patients with single kidney or prior renal irradiationOrgan FunctionRelative
• Pediatric patientsAgeRelative
• Patients with prior extensive myelosuppressive therapyHematologicalRelative

Regulatory Status

• European UnionInvestigationalPhase I/II clinical trials conducted at European nuclear medicine centers; no EMA marketing authorization.
• United StatesInvestigationalNot FDA approved; no IND publicly listed for standard clinical use; preclinical and foreign trial data only.
• United KingdomInvestigationalNo MHRA approval; investigational use only in research settings.

No regulatory approval in any jurisdiction. Investigated in early-phase clinical trials for diagnostic and therapeutic nuclear medicine applications. Various radiolabeled minigastrin analogues have entered Phase I/II trials in Europe.

Evidence & Sources

No sources recorded yet.