Satoreotide Trizoxetan
The imaging half of the JR11 pair, made to show neuroendocrine tumours on PET
Satoreotide trizoxetan is the peptide JR11, which blocks somatostatin receptor 2, joined to a NODAGA cage that holds gallium-68 for PET scans. It is the imaging partner of satoreotide tetraxetan, the same peptide built for lutetium-177 therapy. In small studies it found more liver metastases than standard agonist tracers, with lower background in normal organs. Newer studies use it in small cell lung cancer and in children with neuroblastoma. It is investigational.
Used in human trials: 100-200 MBq with up to 50 µg peptide, Single injection, Intravenous (Gallium-68 satoreotide trizoxetan PET (dose chosen for phase 3)) Details ↓
Recommended Dosing
Used in human trials
No manufacturer dose exists for this use: these are amounts given in published trials, not recommendations.
What is it?
Somatostatin receptor PET with gallium-68 agonist tracers such as DOTATATE and DOTATOC is the standard scan for well-differentiated neuroendocrine tumours. The agonists light up normal liver and spleen as well, which can hide small liver metastases. Satoreotide trizoxetan takes the antagonist route: JR11 binds the receptor without switching it on and is not drawn into the cell, but it can recognise more receptor sites. The imaging version carries a NODAGA chelator for gallium-68, while the therapy version, satoreotide tetraxetan, carries DOTA for lutetium-177; the peptide is the same.
Ipsen's phase 1/2 programme gave the first data. In 12 patients, two scans of 150 MBq with 15 or 50 µg of peptide were well tolerated, the tracer cleared quickly from blood, and the effective dose was similar to other gallium-68 somatostatin tracers; the best scan time was one to two hours. In the phase 2 part, liver lesions had more than twice the contrast of gallium-68 DOTATOC, and lesion-level sensitivity was 88-94% against 59%, with similar positive predictive value. A randomised factorial study in 24 patients then found that 100-200 MBq with up to 50 µg of peptide gave consistent results and was taken forward.
In China, a bicentre study of the first 48 patients compared it with gallium-68 DOTATATE on consecutive days: it found more liver lesions (673 against 584), with twice the contrast, and a lesion sensitivity of 91.7% against 77.2%. A single-centre review of 549 patients scanned with four antagonist tracers, this one among them, found all of them gave higher tumour-to-liver ratios than DOTATATE.
Under its newer code, SSO120, studies have turned to cancers outside the classic neuroendocrine group. In small cell lung cancer it showed tumour in all 31 newly diagnosed patients, with detection similar to FDG PET, and uptake tracked receptor staining on biopsies. In five young children with neuroblastoma, 2 MBq per kg was safe and showed lesions well. These studies are meant to pick patients for a future antagonist radioligand therapy.
Evidence is still small: a few dozen patients per study, mostly single-centre, and no phase 3 result. Satoreotide trizoxetan is made in hospital radiopharmacies for trials, has no FDA or EMA approval, and has no use outside a nuclear-medicine department.
Mechanism of Action
It is a scan agent. The peptide finds somatostatin receptor 2; gallium-68 emits positrons that a PET scanner sees.
Receptor antagonism
Binds somatostatin receptor 2 without activating it and with high affinity (2018 phase 2 study).
Gallium-68 PET
Cleared quickly from blood, with best tumour contrast one to two hours after injection (2018 phase 1 study).
Low normal-organ background
Lower uptake in liver, spleen and other normal organs than gallium-68 DOTATATE, so liver lesions stand out (2023 study).
Theranostic partner
Selects patients for lutetium-177 satoreotide tetraxetan, the same peptide with a DOTA chelator (2026 study).
Published Research
These studies were read from their PubMed abstracts on October 29, 2026: ten in patients, two in mice and one review. The copper-64 version in mice is the same molecule with another metal. One mouse study is titled only for 'antagonist radioligands' and is carded because its abstract names gallium-68 NODAGA-JR11.
Phase 1: safety and radiation dose
Twelve patients with gastroenteropancreatic neuroendocrine tumours had two 150 MBq injections three to four weeks apart (15 and 50 µg peptide). It cleared rapidly from blood; the bladder wall, kidneys and spleen took the highest doses; the effective dose was 0.024 mSv per MBq. Side effects were grade 1-2, and the best imaging window was 1-2 hours.
Phase 2: sensitivity vs gallium-68 DOTATOC
In the same 12 patients, liver-lesion contrast was 5.3 and 4.3 for the two peptide amounts against 1.9 for DOTATOC. Lesion-based sensitivity was 94% and 88% against 59%, with positive predictive values of about 98% for both tracers and no difference between peptide amounts.
Randomised dose-finding study
Twenty-four patients received 5-20 µg and later 30-45 µg of peptide at one of three activity ranges. The scans found at least twice as many lesions as contrast CT, with sensitivity of 85-87% whatever the combination, though the lowest activity range trended lower in the liver. Side effects were mostly mild.
Visual read of the dose-finding scans
Blinded readers scoring image quality as optimal or not gave 56.3% for 40-80 MBq, 90.6% for 100-140 MBq and 81.3% for 160-200 MBq. Peptide amount made no difference, and readers almost always agreed.
Head to head with gallium-68 DOTATATE
In the first 48 patients of a bicentre study, the antagonist detected more liver lesions (673 vs 584) with about twice the contrast and lower uptake in normal organs. Against conventional imaging, lesion sensitivity was 91.7% vs 77.2%. It might have changed management in 7 patients.
Small cell lung cancer staging
Thirty-one newly diagnosed patients had a mean 139 MBq. Tumour showed in every patient and uptake exceeded liver in 90%. Detection of primary, chest node and distant disease was similar to FDG PET, with a few extra liver and brain lesions; the two tracers' uptake correlated poorly.
Lung cancer: PET uptake vs biopsy staining
In 54 patients with small cell lung cancer, uptake in the hottest lesion correlated closely with receptor staining in tumour tissue (rho 0.86). Higher uptake and higher receptor expression went with shorter survival, and almost 40% had high or very high whole-body uptake.
Phase 2: lung neuroendocrine cancers
Nineteen patients with small cell or large cell neuroendocrine lung cancer had 21 scans during or after chemotherapy. Lesions were seen in 18; sensitivity was 82-93% by region. It found fewer small lung and node lesions than CT but 10 extra metastases, mostly in bone.
Children with neuroblastoma
Five children aged 3-7 with stage 4 neuroblastoma received about 2.5 MBq per kg. Seventeen lesions were seen, with a median tumour-to-liver ratio of 4.05. The bladder received the most radiation and the effective dose was 0.088 mSv per MBq; scans at 30 and 60 minutes looked equivalent.
549 patients, four antagonist tracers
A Beijing review of 622 antagonist scans found 91.0% patient-level sensitivity for the tracers combined. For hottest lesions, gallium-68 NODAGA-JR11 uptake was comparable to gallium-68 DOTATATE (SUVmax 39.7 vs 34.3), while all antagonists gave higher tumour-to-liver ratios; NODAGA-LM3 had the best profile.
Case: gastric neuroendocrine tumour
A case report showing gallium-68 DOTATATE and gallium-68 NODAGA-JR11 PET/CT images side by side in one patient with a gastric neuroendocrine tumour.
Copper-64 version vs copper-64 DOTATATE
The antagonist bound with a dissociation constant of 5.7 nM and far more sites than the agonist, stayed mainly on the cell surface and cleared quickly from blood and kidneys in mice, giving rising tumour-to-kidney ratios. Over 80% of tumour uptake was blocked by excess peptide.
Breast cancer model: agonists did better
In mice with ZR-75-1 breast tumours, gallium-68 NODAGA-JR11 had the lowest tumour uptake (12.2% of the dose per gram) and contrast of three tracers, behind DOTATOC and DOTATATE; its affinity was 25.9 nM against about 1 nM for the agonists.
Design of the OPS201/OPS202 pair
Explains the development of JR11 and why the gallium-68 imaging agent uses NODAGA (OPS202) while the lutetium-177 therapy uses DOTA (OPS201), and summarises the preclinical and clinical work on both.
Dosing Data
It has no approved label. It is dosed by radioactivity for a single scan; the rows below are from the carded human studies.
Educational information, not medical advice. Each dose above is tagged with its source: an approved label, a published human study, animal data, or amounts reported by users. None is a recommendation for you. An unapproved compound has no established safe or effective human dose, and products sold for “research use only” are not made or tested for people. Talk to a doctor before acting on anything on this site, including before you start, stop or change any medicine or dose. Full medical disclaimer.
What a Buyer Needs to Know
What is sold, how it is mixed, stored and taken, and what is known about its safety, quality and legal status. Each part names its source. Where we have none, it says unknown.
What is sold
Unknown: we hold no regulator's label that says in what form Satoreotide Trizoxetan is supplied. It is a radioactive drug: the next part says where it is prepared and given.
Mixing a vial: a worked example
Nothing to mix at home, and no syringe units to work out: Satoreotide Trizoxetan is a radioactive drug, prepared and given in nuclear-medicine departments, and its dose is an amount of radioactivity (MBq or GBq), not a weight.
This page's dosing note: “Investigational radioactive imaging agent, prepared and given only in nuclear-medicine departments within studies; these are study activities, not recommendations.”
Source: this page's own note in Dosing Data below; the amount of each dose row in Dosing Data below.
Storage before and after mixing
Unknown: no label on file says how Satoreotide Trizoxetan is stored. It is a radioactive drug held by the nuclear-medicine department that prepares and gives it (see the part above); the home rules for a mixed vial in the mixing guide do not apply to it.
How it is taken
As it was given in human studies: Intravenous (Single injection; Gallium-68 satoreotide trizoxetan PET (dose chosen for phase 3)).
Source: Used in human trials: the route and frequency of each row in Dosing Data below.
What to expect, and when
How long it stays in the body: not established by a measurement cited on this entry.
How long the doses were given: Gallium-68 satoreotide trizoxetan PET (dose chosen for phase 3): Scan at 50-70 minutes; Gallium-68 OPS202 PET, phase 1/2: Two visits 3-4 weeks apart; Gallium-68 SSO120 PET, children with neuroblastoma: Scan up to 60 minutes.
When effects appear: unknown; no source on this page gives a time to effect for Satoreotide Trizoxetan. Results reported in the studies are under Published Research.
Source: Used in human trials, the duration of each row in Dosing Data below.
Side effects, and when to stop or get help
From the Side Effects section: Grade 1-2 adverse events only in the phase 1 study; mostly mild, self-limiting events in the dose-finding study; Radiation: about 3.6 mSv for 150 MBq in adults; 0.088 mSv per MBq in young children. Full list and cautions ↓
When to stop or get help: unknown; no label or trial on file sets rules for stopping Satoreotide Trizoxetan. Treat a severe or unexpected reaction as a reason to stop and see a doctor.
Source: the Side Effects section below (“From the human studies above”).
Interactions
Unknown: a PubMed search for human interaction studies of Satoreotide Trizoxetan (reviewed 2026-10-28) found none. Unknown is not the same as safe to combine.
Every peptide's record, with its source: the interaction matrix.
Checking what you bought
Unknown: no published independent test of Satoreotide Trizoxetan products is in our lab-results database yet, so how products sold under this name measure up is not known.
To read a certificate of analysis, paste it into the COA decoder; it checks the measured mass against Satoreotide Trizoxetan's expected mass, 1,660.2 Da, from this entry's molecular data. Trust & Verification explains what independent testing can and cannot show.
Legal status
US: In Clinical Trials (Not approved: Drugs@FDA and the EMA medicines list hold no record (searched October 28, 2026)). Sport: Prohibited (S0 catch-all).
Country by country ↓ · Regulatory tracker
Source: this entry's approval status and the WADA Prohibited List, as in Legal Status below.
Side Effects & Contraindications
Reported Side Effects
From the human studies above.
Contraindications & Cautions
No approved label exists, so there are no official contraindications. Points from the studies:
Legal Status
Satoreotide trizoxetan is investigational in every jurisdiction checked.
Frequently Asked Questions
?What is satoreotide trizoxetan?
A PET tracer: the somatostatin receptor antagonist JR11 with a NODAGA chelator holding gallium-68. Codes include OPS202 and SSO120.
?How does it relate to satoreotide tetraxetan?
Same peptide, different chelator. Trizoxetan carries gallium-68 for scans; tetraxetan carries lutetium-177 for treatment.
?Is it better than DOTATATE PET?
In two small comparisons it found more liver metastases with better contrast. Large trials have not been reported.
?Is it approved?
No. It is used only within studies.
References
- [other] PubChem CID 119058041 (synonyms satoreotide trizoxetan [INN], NODAGA-JR11, OPS202): formula C73H95ClN18O21S2, molecular weight 1660.2. Read October 28, 2026. https://pubchem.ncbi.nlm.nih.gov/compound/119058041
- [registry] ClinicalTrials.gov API v2, read October 28, 2026: NCT02162446 (phase 1/2, gallium-68 OPS202 in GEP NET, completed); NCT03220217 (phase 2, optimal dose of gallium-68 OPS202, completed).
- [clinical-trial] Nicolas GP, et al. "Safety, Biodistribution, and Radiation Dosimetry of (68)Ga-OPS202 in Patients with Gastroenteropancreatic Neuroendocrine Tumors: A Prospective Phase I Imaging Study." J Nucl Med, 2018;59(6):909-914. PMID: 29025985.
- [clinical-trial] Nicolas GP, et al. "Sensitivity Comparison of (68)Ga-OPS202 and (68)Ga-DOTATOC PET/CT in Patients with Gastroenteropancreatic Neuroendocrine Tumors: A Prospective Phase II Imaging Study." J Nucl Med, 2018;59(6):915-921. PMID: 29191855.
- [clinical-trial] Virgolini I, et al. "A Randomized, Factorial Phase II Study to Determine the Optimal Dosing Regimen for (68)Ga-Satoreotide Trizoxetan as an Imaging Agent in Patients with Gastroenteropancreatic Neuroendocrine Tumors." J Nucl Med, 2022;63(3):376-383. PMID: 34215673.
- [clinical-trial] Miller CG, et al. "A novel read methodology to evaluate the optimal dose of (68)Ga-satoreotide trizoxetan as a PET imaging agent in patients with gastroenteropancreatic neuroendocrine tumours: a phase II clinical trial." EJNMMI Res, 2021;11(1):84. PMID: 34487283.
- [pubmed] Lin Z, et al. "Head-to-Head Comparison of (68)Ga-NODAGA-JR11 and (68)Ga-DOTATATE PET/CT in Patients with Metastatic, Well-Differentiated Neuroendocrine Tumors: Interim Analysis of a Prospective Bicenter Study." J Nucl Med, 2023;64(9):1406-1411. PMID: 37474267.
- [pubmed] Kersting D, et al. "(68)Ga-SSO-120 PET for Initial Staging of Small Cell Lung Cancer Patients: A Single-Center Retrospective Study." J Nucl Med, 2023;64(10):1540-1549. PMID: 37474272.
- [pubmed] Mavroeidi IA, et al. "Theranostics with somatostatin receptor antagonists in SCLC: Correlation of (68)Ga-SSO120 PET with immunohistochemistry and survival." Theranostics, 2024;14(14):5400-5412. PMID: 39310095.
- [clinical-trial] Christensen TN, et al. "Malignancy Detection Rates of [(68)Ga]Ga-SSO120 PET/CT in Patients with Small Cell Lung Cancer and Large Cell Neuroendocrine Lung Cancer." J Nucl Med, 2026;67(4):506-513. PMID: 41506802.
- [pubmed] Teles L, et al. "[(68)Ga]Ga-SSO120 PET/CT Imaging in Pediatric Patients with Neuroblastoma: Biodistribution and Whole-Body Radiation Dosimetry." J Nucl Med, 2026. PMID: 42850043.
- [pubmed] Liu M, et al. "Gallium-68 labeled somatostatin receptor antagonist PET/CT in over 500 patients with neuroendocrine neoplasms: experience from a single center in China." Eur J Nucl Med Mol Imaging, 2024;51(7):2002-2011. PMID: 38337073.
- [pubmed] Lin Z, et al. "68Ga-DOTATATE and 68Ga-NODAGA-JR11 PET/CT Images in a Patient With Gastric Neuroendocrine Tumor." Clin Nucl Med, 2021;46(10):853-855. PMID: 34034328.
- [pubmed] Rylova SN, et al. "The somatostatin receptor 2 antagonist 64Cu-NODAGA-JR11 outperforms 64Cu-DOTA-TATE in a mouse xenograft model." PLoS One, 2018;13(4):e0195802. PMID: 29668724.
- [pubmed] Dude I, et al. "Evaluation of agonist and antagonist radioligands for somatostatin receptor imaging of breast cancer using positron emission tomography." EJNMMI Radiopharm Chem, 2017;2(1):4. PMID: 29503845.
- [review] Mansi R, et al. "Design and development of the theranostic pair (177) Lu-OPS201/(68) Ga-OPS202 for targeting somatostatin receptor expressing tumors." J Labelled Comp Radiopharm, 2019;62(10):635-645. PMID: 31112618.
Sources & Citations
Studies were read from their PubMed records on October 29, 2026. Regulatory status comes from Drugs@FDA and the EMA medicines list (searched October 28, 2026) and trial listings from ClinicalTrials.gov (October 29, 2026). Grey Peptides sells nothing and links to no vendor.
Medical Disclaimer: This content is for educational and informational purposes only. It is not medical advice, and nothing here is an instruction to obtain or use any compound. Talk to a licensed clinician about your own situation.