FPPRGD2
A fluorine-18 PET tracer for the integrin on new blood vessels, tested in small cancer studies
FPPRGD2 is a PET tracer: two small ring-shaped peptides carrying the RGD motif, joined by a short PEG spacer and tagged with radioactive fluorine-18. RGD fits integrin αvβ3, a receptor that growing blood vessels and many tumours carry. Researchers took it into people in 2011 and tested it in breast, brain, cervical, ovarian and kidney cancers, mostly to see whether it can show early that an antiangiogenic drug is working. It is not approved.
Used in human trials: Mean 351.5 MBq (9.5 mCi), ±125.8 MBq, Single injection, Intravenous (Study: first-in-human safety and dosimetry, 5 healthy volunteers) 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 grow only as fast as their blood supply, and the cells lining newly forming vessels carry a receptor, integrin αvβ3, that settled vessels mostly lack. Many cancer cells carry it too. A three-amino-acid motif, arginine-glycine-aspartate (RGD), fits this receptor, and a ring-shaped RGD peptide holds the motif in the shape it binds best. Nuclear medicine has used such peptides to build several tracers that show the receptor on a scan.
FPPRGD2 joins two of those rings, each the cyclic peptide c(RGDyK), on a small branch with a short polyethylene glycol (PEG) spacer, and attaches fluorine-18 for positron emission tomography (PET). In mice the two-ring design gave about twice the binding of the single-ring version, and blocking the receptor or using a non-binding control peptide cut the signal, evidence that what the scan sees is the receptor.
Researchers took it into people in 2011 under an FDA investigational new drug application. Five healthy volunteers tolerated it without changes in vital signs, heart tracings or blood tests. It cleared through the kidneys and bladder, gathered moderately in organs such as the spleen and gut, and left the brain and chest fairly clear. The radiation dose, about 0.04 mSv per MBq, works out at roughly 15 mSv for a 370 MBq injection if the bladder is emptied every hour.
The cancer studies were pilots. In 35 patients the tracer's uptake in tumours did not correlate with FDG, the standard sugar-based PET tracer, which suggests it reports something different. Brain tumours stood out sharply against the normal brain, far more than they did with FDG. In recurrent glioblastoma it found recurrence in 14 of 17 patients against 13 for FDG. In breast cancer, primary tumours and metastases took it up, though less than FDG.
Much of the interest was in watching antiangiogenic drugs. In mice, FPPRGD2 uptake fell within one to three days of starting drugs that attack tumour blood vessels, before tumours shrank, and rose again when treatment stopped. Two small human studies, six women with cervical or ovarian cancer on bevacizumab and seven people with metastatic kidney cancer, saw uptake drop after treatment began. Neither was large enough to show that the drop predicts who will benefit.
The tracer's practical weakness is its synthesis: several steps and nearly three hours, with a low yield. That pushed researchers toward versions of the same peptide labelled more simply, with aluminium fluoride-18 (called alfatide) or gallium-68, which imaged tumours about as well in mice. FPPRGD2 itself remains investigational; its registered trials are completed or withdrawn, and it has not been approved anywhere.
Mechanism of Action
FPPRGD2 carries fluorine-18 to integrin αvβ3, a receptor on endothelial cells in growing blood vessels and on many tumour cells, so a PET scanner can show where the receptor is.
Integrin αvβ3
Two cyclic RGD rings on one molecule fit the receptor; in mice the dimer bound about twice as strongly as a single ring, and blocking cut the signal.
New blood vessels
In treated mouse tumours, falls in uptake matched falls in integrin on tumour vessels, not on the tumour cells themselves.
Early treatment read-out
Uptake dropped one to three days after antiangiogenic drugs in mice, and after bevacizumab or similar drugs in small human studies, before FDG changed.
Clearance
Most of the tracer leaves through the kidneys into the urine; about a quarter is still in the blood at 30 minutes.
Published Research
Studies whose titles name FPPRGD2, read from their PubMed abstracts on October 29, 2026. The human studies, all small, come first; the mouse studies follow, most of them testing whether the tracer shows response to drugs that attack tumour blood vessels. The aluminium fluoride and gallium-68 versions of the peptide are different tracers and appear only where a study compared them with FPPRGD2.
First volunteers: safety and radiation dose
Five healthy volunteers received a mean of 351.5 MBq (9.5 mCi) and were scanned up to three hours. Vital signs, ECGs and blood tests did not change. The tracer left mainly through the kidneys and bladder, with uptake in spleen and large intestine and little above the diaphragm; about a quarter remained in the blood at 30 minutes. The effective dose was 0.0396 mSv per MBq, about 15 mSv for a 370 MBq injection with hourly voiding.
Making a clinical-grade batch
Describes the automated, multi-step synthesis used to make FPPRGD2 for human studies, which took about 170 minutes and gave a radiochemical yield of about 17%. Clinical-grade tracer went mainly to the kidneys and bladder in mice, and a scan of one healthy volunteer showed low background in the head, neck and chest.
Pilot in breast cancer
Eight women with new or recurrent breast cancer had FPPRGD2 and FDG PET/CT within three weeks. The tracer was well tolerated with no change in vital signs, ECGs or blood tests. Primary tumours took it up with a mean SUVmax of 5.6 and metastases 5.0 at 60 minutes, lower than FDG's 10.4 and 6.6.
Where it goes: an atlas in 35 patients
Before treatment, 35 cancer patients were scanned to map uptake in 23 normal tissues. Bladder and kidneys were highest; choroid plexus, salivary glands, thyroid, liver, spleen, pancreas, small bowel and bone were moderate. In 28 patients also scanned with FDG, brain lesions stood out far more with FPPRGD2 (tumour-to-background 13.4 against 1.1), body lesions did not differ, and the two tracers' uptake did not correlate.
Recurrent glioblastoma
Seventeen people with suspected recurrent glioblastoma were scanned before bevacizumab, and some again at one and six weeks. FPPRGD2 PET found recurrence in 14 of 17 (one seen only on FPPRGD2, then confirmed by MRI) against 13 with FDG; no vital-sign, ECG or laboratory changes counted as adverse events. The authors call for larger studies.
Cervical and ovarian cancer on bevacizumab
Six women with cervical or ovarian cancer were scanned before and one week after starting bevacizumab-containing treatment. Lesion uptake was lower than with FDG, fell significantly after one week while normal organs did not change, and in the four patients with follow-up scans the size of the fall loosely tracked clinical response. A pilot of six patients.
Metastatic kidney cancer
Seven patients with metastatic renal cell cancer had 60 lesions imaged with FPPRGD2 and FDG. FPPRGD2 uptake was lower than FDG's (SUVmax 4.4 against 7.8) and fell after antiangiogenic therapy began, by about 29% in SUVmax and 48% in tumour-to-background ratio. The authors suggest it may track early response, pending larger cohorts.
Tracking Abraxane response in mice
In mice with breast-cancer xenografts treated with nanoparticle albumin-bound paclitaxel, tumour FPPRGD2 uptake fell on days 3 and 7 and returned once treatment stopped and tumours relapsed, matching integrin levels in the tumour blood vessels on staining. FDG did not show the early drop. The paper gives the tracer's FDA investigational new drug number, 104150.
Four tracers against a vascular toxin
In breast-cancer mice treated with VEGF121/rGel, a toxin aimed at tumour blood vessels, FPPRGD2 uptake fell by about 24% at day 1 and 36% at day 3 before recovering by day 14; FDG did not change, while FMISO (hypoxia) rose and FLT (cell division) fell.
Early response to a VEGFR-2 inhibitor
In mice given three daily doses of the VEGFR-2 kinase inhibitor ZD4190, tumour FPPRGD2 uptake dropped by about 27% at day 1 and 41% at day 3, then returned to baseline by day 7 as tumours regrew; FDG uptake did not change.
How repeatable is the scan?
Colon-cancer xenografts in 12 mice were scanned twice on the same day, six hours apart. Uptake varied by about 10% to 11% between scans, and tracer uptake matched integrin αvβ3 staining; consistent timing and region size mattered more than body weight, injected amount or fasting.
Dimer against monomer
Kinetic modelling of dynamic scans in tumour-bearing mice found the dimeric tracer FPPRGD2 had about twice the binding potential of the single-ring version FPRGD, and blocking with unlabelled peptide cut binding, as did a control peptide that cannot bind the integrin.
Simpler labels compared
In mice carrying U87MG brain-tumour xenografts, two easier-to-make versions of the same peptide, labelled with aluminium fluoride-18 or gallium-68, imaged tumours as well as FPPRGD2 did, with similar liver, kidney and muscle uptake and mainly urinary clearance. The paper notes FPPRGD2's lengthy multi-step synthesis as the reason to look for alternatives.
Kinetic comparison of the three
Dynamic PET modelling in tumour-bearing mice gave FPPRGD2, its aluminium fluoride-18 version and its gallium-68 version similar binding potentials (about 3.1 to 3.8) despite different uptake on static images.
Aortic aneurysms in mice
In mice with aneurysms of the abdominal aorta induced by angiotensin II, FPPRGD2 uptake in the aortic wall was higher than in controls and correlated strongly with macrophage density and new vessel counts, not with aneurysm diameter, suggesting it marks active disease.
Dynamic versus static scans
In two xenograft models treated with a vascular-disrupting agent, binding potential from dynamic FPPRGD2 scans detected the response of the sensitive tumour by day 1, while uptake from a standard one-hour static image showed it only by day 3; the resistant tumour showed little change by either measure.
Dosing Data
FPPRGD2 has no approved label. This is the activity given in a published human study, as a single injection of a radioactive tracer before PET.
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 FPPRGD2 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: FPPRGD2 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: “FPPRGD2 is dosed by radioactivity and made in a radiopharmacy shortly before the scan, so there is nothing to calculate.”
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 FPPRGD2 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: first-in-human safety and dosimetry, 5 healthy volunteers).
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: first-in-human safety and dosimetry, 5 healthy volunteers: Whole-body PET/CT at 0.5, 1, 2 and 3 hours.
When effects appear: unknown; no source on this page gives a time to effect for FPPRGD2. 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: No changes in vital signs, ECGs or blood tests in healthy volunteers or breast-cancer patients (PMIDs 21502381, 25033190); No changes qualifying as adverse events in the glioblastoma study (PMID 25965900); A radiation dose of about 15 mSv for a 370 MBq injection, with the highest organ dose to the bladder wall (PMID 21502381). Full list and cautions ↓
When to stop or get help: unknown; no label or trial on file sets rules for stopping FPPRGD2. 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 FPPRGD2 (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 FPPRGD2 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 (openFDA, read October 29, 2026) and the EMA medicines list (read October 28, 2026) hold no record). 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
FPPRGD2 is investigational in every jurisdiction checked.
Frequently Asked Questions
?What is FPPRGD2?
A PET tracer made of two ring-shaped RGD peptides joined by a short PEG spacer and tagged with fluorine-18. It binds integrin αvβ3, a receptor on new blood vessels and many tumours.
?What has it been used for?
Small studies in breast cancer, recurrent glioblastoma, cervical, ovarian and kidney cancers, and a 35-patient map of where it goes in the body. The main question was whether it shows early that a drug against tumour blood vessels is working.
?Is it better than an FDG PET scan?
It shows something different. Its uptake did not correlate with FDG's, it was lower in most body tumours, and it made brain tumours stand out much more clearly than FDG. No study was large enough to show it changes treatment decisions.
?How much radiation does it give?
About 0.04 mSv per MBq in the volunteer study, roughly 15 mSv for a 370 MBq injection with voiding every hour; the bladder wall received the highest organ dose.
?Is it approved?
No. Drugs@FDA and the EMA have no record of it. Its registered trials are completed or withdrawn.
References
- [other] ClinicalTrials.gov API v2, read October 29, 2026: NCT01806675 (phase 1/2, 18F-FPPRGD2 PET/CT or PET/MRI in predicting early response to antiangiogenic therapy, completed); NCT01383135 (early phase 1, biodistribution and safety of [18F]FPRGD2 and [18F]FPPRGD2, completed); NCT02995642 (phase 2, vascular inflammation imaging, withdrawn). https://clinicaltrials.gov/search?term=FPPRGD2
- [clinical-trial] Mittra ES, et al. "Pilot pharmacokinetic and dosimetric studies of (18)F-FPPRGD2: a PET radiopharmaceutical agent for imaging α(v)β(3) integrin levels." Radiology, 2011;260(1):182-91. PMID: 21502381.
- [pubmed] Chin FT, et al. "First experience with clinical-grade ([18F]FPP(RGD₂): an automated multi-step radiosynthesis for clinical PET studies." Mol Imaging Biol, 2012;14(1):88-95. PMID: 21400112.
- [clinical-trial] Iagaru A, et al. "(18)F-FPPRGD2 PET/CT: pilot phase evaluation of breast cancer patients." Radiology, 2014;273(2):549-59. PMID: 25033190.
- [clinical-trial] Minamimoto R, et al. "Biodistribution of the ¹⁸F-FPPRGD₂ PET radiopharmaceutical in cancer patients: an atlas of SUV measurements." Eur J Nucl Med Mol Imaging, 2015;42(12):1850-8. PMID: 26062933.
- [clinical-trial] Iagaru A, et al. "Glioblastoma Multiforme Recurrence: An Exploratory Study of (18)F FPPRGD2 PET/CT." Radiology, 2015;277(2):497-506. PMID: 25965900.
- [clinical-trial] Minamimoto R, et al. "Pilot prospective evaluation of (18)F-FPPRGD2 PET/CT in patients with cervical and ovarian cancer." Eur J Nucl Med Mol Imaging, 2016;43(6):1047-55. PMID: 26611425.
- [clinical-trial] Toriihara A, et al. "(18)F-FPPRGD(2) PET/CT in patients with metastatic renal cell cancer." Eur J Nucl Med Mol Imaging, 2019;46(7):1518-1523. PMID: 30850872.
- [pubmed] Sun X, et al. "18F-FPPRGD2 and 18F-FDG PET of response to Abraxane therapy." J Nucl Med, 2011;52(1):140-6. PMID: 21149494.
- [pubmed] Yang M, et al. "Multiplexed PET probes for imaging breast cancer early response to VEGF₁₂₁/rGel treatment." Mol Pharm, 2011;8(2):621-8. PMID: 21280671.
- [pubmed] Yang M, et al. "PET imaging of early response to the tyrosine kinase inhibitor ZD4190." Eur J Nucl Med Mol Imaging, 2011;38(7):1237-47. PMID: 21360246.
- [pubmed] Chang E, et al. "Reproducibility study of [(18)F]FPP(RGD)2 uptake in murine models of human tumor xenografts." Eur J Nucl Med Mol Imaging, 2011;38(4):722-30. PMID: 21125268.
- [pubmed] Guo N, et al. "Quantitative analysis and parametric imaging of 18F-labeled monomeric and dimeric RGD peptides using compartment model." Mol Imaging Biol, 2012;14(6):743-52. PMID: 22437879.
- [pubmed] Lang L, et al. "Comparison study of [18F]FAl-NOTA-PRGD2, [18F]FPPRGD2, and [68Ga]Ga-NOTA-PRGD2 for PET imaging of U87MG tumors in mice." Bioconjug Chem, 2011;22(12):2415-22. PMID: 22026940.
- [pubmed] Guo N, et al. "Quantitative analysis and comparison study of [18F]AlF-NOTA-PRGD2, [18F]FPPRGD2 and [68Ga]Ga-NOTA-PRGD2 using a reference tissue model." PLoS One, 2012;7(5):e37506. PMID: 22624041.
- [pubmed] Kitagawa T, et al. "Integrin-targeted molecular imaging of experimental abdominal aortic aneurysms by (18)F-labeled Arg-Gly-Asp positron-emission tomography." Circ Cardiovasc Imaging, 2013;6(6):950-6. PMID: 23995363.
- [pubmed] Guo N, et al. "Quantitative Evaluation of Tumor Early Response to a Vascular-Disrupting Agent with Dynamic PET." Mol Imaging Biol, 2015;17(6):865-73. PMID: 25896816.
Sources & Citations
Studies were read from their PubMed abstracts on October 29, 2026; trial registrations from ClinicalTrials.gov and status from Drugs@FDA the same day, and the EMA medicines list on October 28, 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.