Edotreotide Peptide: Structure, Research & Science Guide

By The Peptides Codex Editorial TeamReviewed September 7, 2026

Page data last changed: 2026-10-05. Chemistry registry snapshot: 2026-10-01. Registry refreshes and identity assessments are separate from scientific content review.

Length

n/a

Class

DOTA-conjugated somatostatin analogue (radiopharmaceutical carrier)

Function

Somatostatin receptor agonist that carries a radionuclide to somatostatin-receptor-positive tumours for imaging (gallium-68) or therapy (lutetium-177)

Context

Approved (EMA, 2016) as gallium-68 edotreotide for PET imaging of gastroenteropancreatic neuroendocrine tumours; lutetium-177 edotreotide in phase 3 for therapy

One peptide, two jobs: with gallium-68 it lights up neuroendocrine tumours on a PET scan; with lutetium-177 it irradiates them.

Also known as: DOTATOC · SMT 487 · SMT-487 · 68Ga-DOTATOC · 177Lu-edotreotide

Part of the Foundational & therapeutic peptides cluster

Overview

Edotreotide (DOTATOC) is a somatostatin receptor agonist peptide conjugated to the chelator DOTA so that it can carry a radiometal to somatostatin-receptor-positive tumours. Labelled with gallium-68 it is an EMA-approved (2016) PET imaging agent for gastroenteropancreatic neuroendocrine tumours; labelled with lutetium-177 it delivers targeted radiation, and in the phase 3 COMPETE trial it extended median progression-free survival to 23.9 months versus 14.1 months with everolimus.

Source & context

Biological / chemical source: Synthetic somatostatin analogue conjugated to the chelator DOTA

Primary research or clinical context: Approved (EMA, 2016) as gallium-68 edotreotide for PET imaging of gastroenteropancreatic neuroendocrine tumours; lutetium-177 edotreotide in phase 3 for therapy

What edotreotide is

Edotreotide, better known in nuclear medicine as DOTATOC, is a somatostatin receptor agonist peptide attached to DOTA, a macrocyclic chelator that grips radioactive metal ions. The peptide finds the target — somatostatin receptors, which neuroendocrine tumours over-express — and the chelator determines what it delivers. Loaded with gallium-68, a positron emitter, it is a PET imaging agent for gastroenteropancreatic neuroendocrine tumours, approved by the EMA in 2016 (IUPHAR record). Loaded with lutetium-177, a beta emitter, it becomes a peptide receptor radionuclide therapy (PRRT) that irradiates those tumours from within.

Structure

Edotreotide belongs to the octreotide family of somatostatin analogues — short, disulfide-cyclised peptides that keep somatostatin's receptor-binding core in a protease-resistant ring — with DOTA coupled at the N-terminus. The molecular formula of the unlabelled peptide, C65H92N14O18S2, and its mass of about 1,422 Da are from the PubChem record; the two sulfurs are the cysteine pair that closes the ring. Because the sequence in the evidence for this profile is not given residue by residue, no one-letter chips are shown; the octreotide profile on this site illustrates the shared scaffold.

Imaging: gallium-68 edotreotide

Ga-68 DOTATOC PET/CT localises somatostatin-receptor-positive neuroendocrine tumours with a sensitivity that has made receptor PET the standard for staging. Beyond detection, the amount of receptor-positive tumour on a scan carries prognostic information: in metastatic gastroenteropancreatic NETs, the total somatostatin-receptor tumour volume measured on Ga-68 edotreotide PET/CT was studied as a predictor of outcome (Gallicchio et al., Cancer Control 2026). A direct comparison of Ga-68 DOTATATE and Ga-68 DOTATOC — the two most used imaging agents — was registered but withdrawn on ClinicalTrials.gov. US labelling advises nursing mothers to pump and discard milk for eight hours after a dose (LactMed 2025).

Therapy: lutetium-177 edotreotide and the COMPETE trial

COMPETE was a phase 3, open-label superiority trial at 49 specialist centres in 14 countries, randomising 309 patients with unresectable or metastatic grade 1–2 gastroenteropancreatic NETs 2:1 to intravenous 177Lu-edotreotide (207 patients) or everolimus (102). Median progression-free survival was 23.9 months with 177Lu-edotreotide versus 14.1 months with everolimus (stratified hazard ratio 0.67, 95% CI 0.48–0.95; p = 0.022). Treatment-related adverse events occurred in 82% versus 97%, and grade 3–4 events in 18% versus 40%; the most common with 177Lu-edotreotide were diarrhoea and nausea (36% each) and asthenia (33%) (Walter et al., Lancet 2026).

COMPETE (Walter et al., Lancet 2026)
Endpoint	177Lu-edotreotide (n = 207)	Everolimus (n = 102)
Median progression-free survival	23.9 months	14.1 months
Hazard ratio (95% CI)	0.67 (0.48–0.95); p = 0.022	—
Treatment-related adverse events	82%	97%
Grade 3–4 treatment-related events	18%	40%

Ongoing therapeutic trials

The LEVEL trial extends the same comparison to progressive, well- or moderately-differentiated neuroendocrine tumours of the lung and thymus, where everolimus is the only approved therapy and SSTR2 expression is common on imaging (Capdevila et al., BMC Cancer 2025). ClinicalTrials.gov lists 75 studies mentioning edotreotide as of the September 2026 snapshot, including phase 1 work on newer radionuclides carried by the same peptide, and a 2026 systematic review and meta-analysis pooled the efficacy and safety of 177Lu-edotreotide across neuroendocrine tumour studies (Baum et al., Journal of Neuroendocrinology 2026). PRRT with radiolabelled somatostatin analogues has been used for more than two decades (Puliani et al., Frontiers in Endocrinology 2022).

Status as of September 2026

Gallium-68 edotreotide is an approved diagnostic radiopharmaceutical in the EU (2016); the IUPHAR record and US lactation labelling indicate diagnostic use in the United States as well. Lutetium-177 edotreotide had completed phase 3 but no approval for the therapeutic form appears in the evidence for this profile. Both are hospital-administered radioactive agents; nothing here is guidance on their use.

Relation to other peptides on this site

Octreotide, lanreotide, vapreotide and pasireotide — all profiled here — are the therapeutic somatostatin analogues from which edotreotide's targeting peptide descends. Edotreotide shows the theranostic extension of that family: the same receptor-binding ring, repurposed as a delivery vehicle for imaging and radiation.

Structure & chemistry

Molecular identity & reference confidence

Source-supported reference

Reference values are taken from the cited molecular record or curated profile. A database match is not independent laboratory verification; modifications, counter-ions, and formulations can change the measured mass.

Molecular form: Somatostatin analogue peptide (octreotide family) with the macrocyclic chelator DOTA attached for radiometal binding
Species: Not established by this molecular identity audit
Termini (N / C): Not specified / Not specified

Average reference mass

Reference policy updated: 2026-10-05

IUPHAR/BPS source snapshot · 2026-10-01
PubChem molecular record · 2026-10-01

Molecular formula: C65H92N14O18S2
Average reference mass: ≈ 1,421.6
Receptors: Somatostatin receptors (SSTR), particularly SSTR2, which are over-expressed on neuroendocrine tumours
Backbone: Somatostatin analogue peptide (octreotide family) with the macrocyclic chelator DOTA attached for radiometal binding
Status: Approved: EMA, 2016 (68Ga-edotreotide for PET imaging of GEP-NETs). 177Lu-edotreotide in phase 3 (COMPETE, LEVEL)

Identifiers

PubChem CID: 158782
IUPHAR ligand: 5638
CAS RN: 204318-14-9
UNII: U194AS08HZ

Chemistry values: curated profile, PubChem, IUPHAR/BPS Guide to Pharmacology · fetched 2026-10-01.

Clinical development snapshot

ClinicalTrials.gov lists 75 registered studies with “Edotreotide” as an intervention (snapshot 2026-10-01). A registry footprint is not evidence of efficacy or approval.

Registered studies

Highest phase reached

Phase 3

Active in latest 100

Most recent update

2026-09-25

Most recently updated studies
NCT	Title	Phase	Status	Updated
NCT06441331	Phase I Trial to Determine the Dose and Evaluate the PK and Safety of Lutetium Lu 177 Edotreotide Therapy in P	Phase 1	recruiting	2026-09-25
NCT04298541	Direct Comparison of Ga-68-DOTATATE and Ga-68-DOTATOC	Phase 2	withdrawn	2026-08-31
NCT07150806	RYZ101 for the Treatment of Progressive or Recurrent Intracranial Meningioma	Phase 2	recruiting	2026-08-13
NCT04609592	Study of PRRT in Metastatic, WHO Grade 1 or 2, SSTR Positive, GEP-NET Who Are Candidates for Cytoreductive Sur	Phase 1	active not recruiting	2026-08-12
NCT03049189	Efficacy and Safety of 177Lu-edotreotide PRRT in GEP-NET Patients	Phase 3	active not recruiting	2026-08-07
NCT05691465	Testing the Safety and Effectiveness of Radiation-based Treatment (Lutetium Lu 177 Dotatate) for Metastatic Pr	Phase 2	recruiting	2026-07-14

See all on ClinicalTrials.gov →

Concentration math

Edotreotide — reconstitution calculator

Enter how much peptide is in the vial and how much diluent (e.g. bacteriostatic water) is added. The tool returns the resulting solution concentration — and, for any amount you type, the volume it corresponds to. This is educational arithmetic, not a dosing recommendation.

Reference form: Somatostatin analogue peptide (octreotide family) with the macrocyclic chelator DOTA attached for radiometal bindingAverage reference mass: 1,421.6 Da

Peptide in vial (mg)

Diluent added (mL)

Syringe graduation

Solution concentration

5 mg/mL5,000 mcg/mL

Amount to measure (optional)

mcg

Enter an amount to see the volume it corresponds to.

Educational concentration mathematics only. This tool does not recommend a dose, amount, or protocol, and nothing here is medical advice. Many peptides are not authorized by Health Canada for human use — see our reconstitution and bacteriostatic-water guides for context.

Open the Edotreotide calculator on its own page →

Change log

Dated observations from the data pipeline (registry flags, trial footprints, identifiers) and editorial reviews of this profile.

2026-09-07IdentifiersCross-linked to IUPHAR ligand 5638 and PubChem CID 158782.
2026-09-07TrialsClinicalTrials.gov snapshot added: 75 registered studies, highest phase 3.
2026-09-07EditorialProfile content reviewed and updated by the editorial team.

FAQ about Edotreotide

What is Edotreotide?+

What Canadian product status is recorded for Edotreotide?+

Canadian product status for Edotreotide has not been verified in this profile. No verified record here does not mean no authorization exists. Status depends on the product, formulation and use; consult Health Canada's product records.

What is the typical length of Edotreotide?+

Edotreotide is not a classic amino-acid chain peptide in the same sense; see the profile for classification details.

What is edotreotide?+

DOTATOC — a somatostatin analogue peptide conjugated to the chelator DOTA. Labelled with gallium-68 it images neuroendocrine tumours by PET (EMA-approved 2016); labelled with lutetium-177 it treats them.

What is the difference between DOTATOC and DOTATATE?+

Both are DOTA-conjugated somatostatin analogues used for the same purposes; they differ in the peptide's C-terminal residue. A direct imaging comparison trial was registered but withdrawn.

What did the COMPETE trial show?+

In grade 1–2 gastroenteropancreatic NETs, 177Lu-edotreotide extended median progression-free survival to 23.9 months versus 14.1 months with everolimus (hazard ratio 0.67), with fewer grade 3–4 adverse events (18% vs 40%).

Is edotreotide a treatment or a diagnostic?+

Both, depending on the radionuclide: gallium-68 for PET imaging (approved), lutetium-177 for peptide receptor radionuclide therapy (phase 3 completed).

How does edotreotide reach tumours?+

Its peptide binds somatostatin receptors, especially SSTR2, which neuroendocrine tumours over-express; the attached DOTA carries the radiometal.

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References & further reading

Disclaimer: Educational content only. Not medical advice. Not instructions for human use. Research peptides and unapproved products may be restricted or illegal to market for human consumption in your jurisdiction. Consult qualified professionals and applicable law.

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