3PRGD2
A technetium-99m tracer for new blood vessels, studied in lung, breast and oesophageal cancer
3PRGD2 is a small, twin-ringed peptide that binds integrin αvβ3, a receptor that growing blood vessels and many tumours carry. Labelled with technetium-99m, it shows those tissues on a SPECT scan, the kind of gamma camera most hospitals have. It has been studied mainly in China, including a completed phase 3 lung-cancer study, and is not approved anywhere checked.
Used in human trials: 11.1 MBq per kg body weight, Single injection, Intravenous (Study: multicentre lung-cancer imaging, 70 patients) 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?
Tumours need blood vessels to grow, and the cells lining new vessels carry a receptor called integrin αvβ3 that mature vessels mostly lack. Many tumour cells carry it too. A short peptide motif, arginine-glycine-aspartate or RGD, fits this receptor, and nuclear medicine has turned RGD peptides into several tracers. Most are PET tracers labelled with fluorine-18 or gallium-68, such as galacto-RGD. 3PRGD2 takes a different route: it carries technetium-99m, so it works on a SPECT camera, which is cheaper and far more widely available than PET.
The molecule is two copies of the cyclic peptide c(RGDfK) joined on a small branch, with three short polyethylene glycol (PEG4) spacers and a HYNIC group that holds the technetium. Its developers chose this design for its αvβ3 targeting, and after the human lung results they labelled the same peptide with lutetium-177, which slowed tumour growth in mice, so it has also been explored as a carrier for radiation treatment.
The first large human study, in 2012, imaged 70 people with suspected lung lesions at six Chinese centres one hour after injection. It picked up most lung cancers, with a sensitivity of 88% to 97% depending on how the images were read, but it also lit up some benign lesions, giving a specificity of only 58% to 67%. That pattern, sensitive but not very specific in the primary tumour, recurs across the literature, because inflammation and benign growths also build new vessels. A 2022 case report described sarcoidosis that looked like lung cancer on the scan.
Where 3PRGD2 has stood out is in lymph nodes and bone. In 65 people with suspected lung cancer it was as sensitive as FDG PET for nodal spread and much more specific (95% against 75%), and a 2023 study found similar figures. In oesophageal cancer it beat CT for nodal staging in one study and was comparable to FDG PET in two others. Against a standard bone scan in 44 lung-cancer patients, it was more specific (91% against 61%), since it does not light up healing or degenerative bone.
Because uptake tracks blood-vessel activity, several studies used the scan to judge early whether a treatment was working. A drop in uptake after one or two cycles predicted pathological response to chemotherapy before breast-cancer surgery, response and survival in lung cancer treated with chemoradiotherapy and bevacizumab, and progression-free survival on EGFR inhibitors. In thyroid cancer that no longer takes up radioiodine, it found every target lesion in 10 patients and recurrent disease in most of 37 others, which matters because those tumours are candidates for anti-angiogenic drugs.
Smaller studies have tried it in breast lumps, choroidal melanoma of the eye and rheumatoid arthritis, where inflamed joint lining also grows new vessels. ClinicalTrials.gov lists a 409-patient phase 3 lung-cancer study as completed; its results were not among the abstracts read. 3PRGD2 is not approved by FDA or the EMA, and it is made only in hospital radiopharmacies for studies.
Mechanism of Action
3PRGD2 carries technetium-99m to integrin αvβ3, a receptor on endothelial cells in growing blood vessels and on many tumour cells, so a SPECT camera can show where new vessels are forming.
Integrin αvβ3
Two cyclic RGD rings on one molecule, each fitting αvβ3; the lutetium-177 study describes the design as an advantage for targeting the receptor.
New blood vessels
Uptake tracked αvβ3 staining and microvessel density in resected lung and oesophageal tumours.
SPECT imaging
The HYNIC group holds technetium-99m, which ordinary gamma cameras image; scans were taken from 30 minutes to 4 hours after injection.
Inflammation shows too
Inflamed tissue such as sarcoid granulomas and arthritic joints also grows new vessels, which lowers specificity in the primary tumour.
Published Research
Studies whose titles name 3PRGD2, read from their PubMed abstracts on October 29, 2026. Human imaging studies come first; the animal work includes a lutetium-177 version of the same peptide. The albumin-binding derivative AB-3PRGD2 is a different molecule and is not included.
Multicentre lung study
Seventy people with suspected lung lesions (58 cancers, 12 benign) at six centres received 11.1 MBq/kg. Most cancers were clear at one hour; sensitivity was 88% by tumour-to-background ratio and 93% to 97% by visual reading, but specificity was only 58% to 67%. Most lymph-node and bone metastases were also seen.
Lymph nodes in lung cancer, against FDG
In 65 people with suspicious lung lesions who had both scans, 3PRGD2 SPECT/CT matched FDG PET/CT in sensitivity for nodal metastasis (88.3% vs 90.7%) and was more specific (94.6% vs 75.0%). Uptake correlated with αvβ3 expression and microvessel density in resected tissue.
Lymph nodes in lung cancer, 2023
In 26 patients with primary lung cancer, 3PRGD2 SPECT/CT separated metastatic from benign node stations with an area under the curve of 0.91, sensitivity 86% and specificity 88%; uptake in the primary tumour itself also predicted nodal spread.
Bone metastases against the bone scan
Forty-four people with suspected lung cancer at four centres received 11.1 MBq/kg. Lesion by lesion, 3PRGD2 had 92.1% sensitivity and 91.3% specificity, against 87.6% and 60.9% for the standard MDP bone scan; it was better at ruling out false positives and finding metastases that do not form new bone.
Predicting response to chemoradiotherapy plus bevacizumab
In 28 patients with advanced non-squamous lung cancer, baseline uptake did not separate responders from non-responders, but a fall of more than about 26% after two cycles did (area under the curve 0.86), and those with larger falls lived longer.
Early response to EGFR inhibitors
In 18 patients with lung adenocarcinoma, a fall in uptake of at least 23.8% after treatment identified responders with 80% sensitivity and 87.5% specificity; median progression-free survival was 18 months in scan responders against 7 months in non-responders.
Breast cancer chemotherapy before surgery
Thirty-three women with stage II or III breast cancer were scanned before and after the first two chemotherapy cycles. Among those with visible baseline uptake, the change after cycle two predicted pathological response with about 93% sensitivity and specificity; HER2-positive tumours showed the highest uptake and largest changes.
Breast cancer against FDG
In 42 women with 45 breast lesions, visual reading gave 97.4% sensitivity and 87.5% specificity, against 97.4% and 71.4% for FDG PET; for armpit nodes FDG was a little more sensitive (85% vs 78%), and both found all nine patients with distant spread.
Breast lesions against mammography
In 72 women, SPECT/CT at 4 hours was more sensitive and accurate than mammography in dense breasts (95.2% sensitivity and 90.7% accuracy against 71.4% and 68.5%), and combining the two reached 98.3% sensitivity and 96.0% accuracy.
Reading breast scans by eye and by numbers
In 72 women with 89 breast lesions given about 749 MBq, visual and tumour-to-background readings performed similarly (around 77% accuracy), and combining them raised sensitivity, specificity and accuracy to 87.5%, 82.9% and 85.4%.
Oesophageal cancer nodes against CT
In 32 patients who then had surgery with node dissection, 3PRGD2 SPECT was more accurate than CT per node (85.1% vs 69.6%) and per patient (87.5% vs 62.5%), and staged the nodes correctly in 78% against 53%.
Oesophageal cancer against FDG
In 29 patients given 11.1 MBq/kg, chest SPECT/CT performed like FDG PET/CT for the primary tumour (semi-quantitative sensitivity 87%, specificity 100%), uptake tracked αvβ3 expression, and it seemed less sensitive for small involved nodes.
Oesophageal squamous cancer nodes, 2024
In 15 patients scanned before surgery, SPECT/CT detected metastatic node stations with 62.5% sensitivity and 91.3% specificity, against 70.8% and 83.7% for FDG PET/CT, differences that were not significant.
Thyroid cancer resistant to radioiodine
In 10 patients with raised thyroglobulin and negative iodine-131 scans, every target lesion took up 3PRGD2, and uptake correlated with how fast the lesions had been growing (r = 0.88).
Recurrent thyroid cancer, 37 patients
In patients with raised thyroglobulin but negative radioiodine scans, SPECT/CT was positive in 30 of 37, with 96.6% sensitivity and 75% specificity for recurrence at follow-up; it performed better at higher thyroglobulin levels.
Choroidal melanoma
Ten patients with melanoma of the eye were scanned before and three months after plaque brachytherapy. Tumours showed focal uptake about twice the normal side, higher with retinal detachment, falling after treatment, and uptake rose with tumour volume.
Case: sarcoidosis mimicking lung cancer
A 57-year-old with papillary thyroid cancer had growing lung lesions with focal 3PRGD2 uptake; biopsy and the course of treatment showed sarcoidosis, a reminder that inflamed tissue with new vessels also takes it up.
Rheumatoid arthritis in rats and a patient
In rats with collagen-induced arthritis, joint uptake rose two weeks after immunisation, before a bone scan could tell diseased from healthy joints, and fell with bevacizumab; a patient with rheumatoid arthritis showed higher joint uptake than a healthy volunteer.
Arthritis model in rats
Ankle uptake in a rat arthritis model rose with the arthritis score, from 0.64 to 1.73% of the injected dose per gram at one hour, and correlated with αvβ3 staining (r = 0.85); the tracer left through the urine.
Distribution and chemotherapy in rabbits
In 18 rabbits with VX2 tumours, the tracer cleared from the heart within minutes but stayed in tumours (half-life about 71 minutes); after cisplatin, tumour uptake and its timing changed before the tumours shrank.
Lutetium-177 3PRGD2 as treatment in mice
Labelled with lutetium-177, the peptide reached 6.0% of the injected dose per gram in glioma xenografts at one hour and slowed tumour growth; two doses, or one combined with the anti-angiogenic drug Endostar, worked better than one, and mice tolerated over 111 MBq.
Review of clinical oncology studies
A 2022 review of 99mTc-3PRGD2 SPECT in people, covering diagnosis and staging in lung, breast, oesophageal and head and neck cancers and its use in judging treatment response.
Dosing Data
3PRGD2 has no approved label. These are activities given in published human studies, as a single injection of a radioactive tracer before SPECT.
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 3PRGD2 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: 3PRGD2 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: “3PRGD2 is dosed by radioactivity and prepared in a hospital radiopharmacy shortly before the scan in nuclear-medicine departments.”
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 3PRGD2 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; Study: multicentre lung-cancer imaging, 70 patients).
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: Study: multicentre lung-cancer imaging, 70 patients: Whole-body images at 1 hour, chest SPECT at 4 hours; Study: breast lesions, 72 patients: SPECT at 60 minutes.
When effects appear: unknown; no source on this page gives a time to effect for 3PRGD2. 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: A single diagnostic injection; the abstracts read give no side-effect data; The tracer leaves mainly through the kidneys and urine (rat study). Full list and cautions ↓
When to stop or get help: unknown; no label or trial on file sets rules for stopping 3PRGD2. Treat a severe or unexpected reaction as a reason to stop and see a doctor.
Source: the Side Effects section below (“From the studies above”).
Interactions
Unknown: a PubMed search for human interaction studies of 3PRGD2 (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 3PRGD2 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. 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 29, 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 studies above. None of the abstracts read reports an adverse reaction to the tracer.
Contraindications & Cautions
No approved label exists, so there are no official contraindications. Points from the studies above:
Legal Status
3PRGD2 is investigational in every jurisdiction checked.
Frequently Asked Questions
?What is 3PRGD2?
A tracer made of two ring-shaped RGD peptides joined by short PEG spacers, carrying technetium-99m. It binds integrin αvβ3 on new blood vessels and tumour cells, so a SPECT scan can show them.
?Is it approved?
No. Drugs@FDA and the EMA have no record of it. A phase 3 lung-cancer study with 409 participants is listed as completed on ClinicalTrials.gov.
?Why use technetium instead of a PET isotope?
Technetium-99m works with SPECT gamma cameras, which are cheaper and more widely available than PET scanners, so the scan could reach hospitals without PET.
?How does it compare with FDG PET?
For primary tumours it performed about as well in several studies. For lymph nodes it was usually more specific, giving fewer false positives, but it could miss small nodes.
?Can it show whether a treatment is working?
In small studies a fall in uptake after one or two cycles predicted response to chemotherapy in breast cancer, and response and survival on bevacizumab-based treatment or EGFR inhibitors in lung cancer.
?Can it give false positives?
Yes. Benign lung lesions and inflammation, such as sarcoidosis, can take it up, which is why its specificity for primary lung tumours was only 58% to 67% in the first large study.
?How does it relate to the other RGD tracers?
Galacto-RGD, fluciclatide, alfatide II and FPPRGD2 target the same receptor with PET isotopes; 3PRGD2 is the technetium-99m SPECT version. Cilengitide is an RGD peptide given as a drug to block the receptor.
References
- [registry] ClinicalTrials.gov API v2, read October 29, 2026: NCT04233476 (phase 3, 99mTc-3PRGD2 SPECT/CT in lung cancer, 409 participants, completed); NCT01737112 (early phase 1, lung cancer, status unknown); NCT02744729 (early phase 1, oesophageal cancer, completed); NCT02742168 (breast cancer, completed); NCT02723760 (early phase 1, rheumatoid arthritis, completed).
- [clinical-trial] Zhu Z, et al. "99mTc-3PRGD2 for integrin receptor imaging of lung cancer: a multicenter study." J Nucl Med, 2012;53(5):716-22. PMID: 22499615.
- [pubmed] Zhao D, et al. "Integrin αvβ3 imaging of radioactive iodine-refractory thyroid cancer using 99mTc-3PRGD2." J Nucl Med, 2012;53(12):1872-7. PMID: 23071350.
- [clinical-trial] Miao W, et al. "Comparison of 99mTc-3PRGD2 integrin receptor imaging with 99mTc-MDP bone scan in diagnosis of bone metastasis in patients with lung cancer: a multicenter study." PLoS One, 2014;9(10):e111221. PMID: 25338281.
- [pubmed] Ji B, et al. "⁹⁹mTc-3PRGD₂ SPECT to monitor early response to neoadjuvant chemotherapy in stage II and III breast cancer." Eur J Nucl Med Mol Imaging, 2015;42(9):1362-70. PMID: 25947573.
- [pubmed] Ma Q, et al. "(99m)Tc-3PRGD 2 SPECT/CT predicts the outcome of advanced nonsquamous non-small cell lung cancer receiving chemoradiotherapy plus bevacizumab." Ann Nucl Med, 2015;29(6):519-27. PMID: 25911312.
- [pubmed] Zhang Z, et al. "(99m)Tc-3PRGD2 SPECT/CT Imaging for Monitoring Early Response of EGFR-TKIs Therapy in Patients with Advanced-Stage Lung Adenocarcinoma." Cancer Biother Radiopharm, 2016;31(7):238-45. PMID: 27563805.
- [pubmed] Jin X, et al. "Integrin Imaging with (99m)Tc-3PRGD2 SPECT/CT Shows High Specificity in the Diagnosis of Lymph Node Metastasis from Non-Small Cell Lung Cancer." Radiology, 2016;281(3):958-966. PMID: 27479638.
- [pubmed] Lv N, et al. "Advantages of (99m)Tc-3PRGD(2) SPECT over CT in the preoperative assessment of lymph node metastasis in patients with esophageal cancer." Ann Nucl Med, 2019;33(1):39-46. PMID: 30218281.
- [pubmed] Zheng S, et al. "[(99m)Tc]3PRGD(2) for integrin receptor imaging of esophageal cancer: a comparative study with [(18)F]FDG PET/CT." Ann Nucl Med, 2019;33(2):135-143. PMID: 30392070.
- [pubmed] Chen Z, et al. "Comparison of [(99m)Tc]3PRGD(2) Imaging and [(18)F]FDG PET/CT in Breast Cancer and Expression of Integrin α(v)β(3) in Breast Cancer Vascular Endothelial Cells." Mol Imaging Biol, 2018;20(5):846-856. PMID: 29497956.
- [pubmed] Chen G, et al. "Evaluation of Tc-99m-3PRGD2 Integrin Receptor Imaging in the Differential Diagnosis of Breast Lesions and Comparison With Mammography." Cancer Invest, 2017;35(2):108-115. PMID: 28135863.
- [pubmed] Chen Q, et al. "Diagnostic value of (99m)Tc-3PRGD2 scintimammography for differentiation of malignant from benign breast lesions: Comparison of visual and semi-quantitative analysis." Hell J Nucl Med, 2015;18(3):193-8. PMID: 26574690.
- [pubmed] Gao R, et al. "Clinical Value of (99m)Tc-3PRGD2 SPECT/CT in Differentiated Thyroid Carcinoma with Negative (131)I Whole-Body Scan and Elevated Thyroglobulin Level." Sci Rep, 2018;8(1):473. PMID: 29323252.
- [pubmed] Xiao L, et al. "(99m)Tc-3PRGD(2) SPECT/CT Imaging for Diagnosing Lymph Node Metastasis of Primary Malignant Lung Tumors." Korean J Radiol, 2023;24(11):1142-1150. PMID: 37899523.
- [pubmed] Wang X, et al. "Prospective study of (99m)Tc-3PRGD(2) SPECT/CT diagnosing metastatic lymph nodes in esophageal squamous cell carcinoma." Thorac Cancer, 2024;15(27):1958-1967. PMID: 39140206.
- [pubmed] Yan B, et al. "99mTc-3PRGD2 single-photon emission computed tomography/computed tomography for the diagnosis of choroidal melanoma: A preliminary STROBE-compliant observational study." Medicine (Baltimore), 2018;97(40):e12441. PMID: 30290601.
- [pubmed] Yang Y, et al. "Sarcoidosis Mimicking Primary Lung Cancer on (99m)Tc-3PRGD2 Scintigraphy in a PTC Patient." Diagnostics (Basel), 2022;12(6). PMID: 35741228.
- [pubmed] Wu Y, et al. "Early detection of rheumatoid arthritis in rats and humans with 99mTc-3PRGD2 scintigraphy: imaging synovial neoangiogenesis." Oncotarget, 2017;8(4):5753-5760. PMID: 27992368.
- [pubmed] Huang C, et al. "Study of novel molecular probe 99mTc-3PRGD2 in the diagnosis of rheumatoid arthritis." Nucl Med Commun, 2015;36(12):1208-14. PMID: 26352213.
- [pubmed] Wu JG, et al. "Biometabolic Distribution of 99mTc-3PRGD2 and Its Potential Value in Monitoring Chemotherapeutic Effects." Mol Imaging, 2015;14(12):11-12. PMID: 26650015.
- [pubmed] Shi J, et al. "Anti-tumor effect of integrin targeted (177)Lu-3PRGD2 and combined therapy with Endostar." Theranostics, 2014;4(3):256-66. PMID: 24505234.
- [review] Xiao L, et al. "Advances in Clinical Oncology Research on (99m)Tc-3PRGD2 SPECT Imaging." Front Oncol, 2022;12:898764. PMID: 35712468.
Sources & Citations
Studies were read from their PubMed abstracts on October 29, 2026; trial registrations from ClinicalTrials.gov and status from Drugs@FDA and the EMA medicines list, read the same days. 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.