Elpamotide
A nine-amino-acid piece of a blood-vessel receptor, injected to turn the immune system against tumour vessels
Elpamotide is a short synthetic peptide copied from VEGFR2, the receptor that growing blood vessels use to read the signal VEGF. The idea behind it was indirect: rather than attacking cancer cells, teach cytotoxic T cells to recognise the cells lining tumour vessels, which carry VEGFR2 while settled adult vessels largely do not. It was developed in Japan under the codes VEGFR2-169 and OTS-102, reached a randomised phase 2/3 trial in advanced pancreatic cancer alongside gemcitabine, and did not prolong survival. Nothing was approved, and the developer's trials ended there.
Used in human trials: 2 mg, Once a week, Subcutaneous, as a water-in-oil emulsion with Montanide ISA51 VG (Study: PEGASUS-PC phase 2/3, pancreatic cancer) 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?
A tumour cannot grow far without new blood vessels, and the switch that tells vessel-lining cells to grow is VEGFR2, the main receptor for vascular endothelial growth factor. Most drugs aimed at that switch block it directly: an antibody that mops up VEGF, an antibody against the receptor itself, or a small molecule that stops the receptor signalling inside the cell. Elpamotide takes a different route. It is not a blocker at all, but a fragment of the receptor used as a vaccine antigen: nine amino acids from the receptor's outer region, injected under the skin so that T cells learn to kill the cells displaying them.
The fragment was picked because of how human immune cells read proteins. A cytotoxic T cell sees short peptides held in the groove of an HLA class I molecule on a cell's surface, and each HLA type holds a different shape of peptide. The nine residues of elpamotide, taken from positions 169 to 177 of VEGFR2, fit HLA-A*24:02. Every trial of the peptide therefore screened patients for that one tissue type before enrolling them, which is the first thing to understand about the programme: it could only ever have helped people who carry that one HLA type.
Through the 2000s a group in Japan worked up VEGFR2 peptides from laboratory work into early trials, and the compound acquired three names that still appear interchangeably in the literature: VEGFR2-169 in the earliest clinical papers, OTS-102 as a company code, and elpamotide once it received an international nonproprietary name. The peptide itself never changed. On this page all three refer to the same nine amino acids.
The clinical story runs through pancreatic cancer. A phase 1 trial combined weekly injections with standard gemcitabine and found the combination tolerable, with peptide-specific T cells raised in most patients and reactions at the injection site in most of them. That led to PEGASUS-PC, a placebo-controlled phase 2/3 trial in 153 patients, which measured overall survival and found no difference between the two arms: a median of about eight and a half months either way. A single-arm phase 2 trial in biliary tract cancer reported longer survival than historical figures, and a two-peptide vaccine including this one was tested with chemotherapy in gastric cancer, but neither design can show that the vaccine itself was responsible.
What survives is a consistent and unusual observation. In both of the later trials, the patients whose injection sites reacted hardest lived longest. In the randomised trial, severe local reactions happened only in the arm that received the peptide, and those patients had a median survival roughly twice that of everyone else; in the biliary trial the gap was 14.8 months against 5.7. That is a correlation inside a treated group, not evidence of benefit, and it can simply mark the people whose immune systems were in better shape. The honest summary is that elpamotide did what it was designed to do immunologically and still did not help people live longer, which is why the programme stopped.
Mechanism of Action
The peptide does nothing to VEGFR2 itself. It is an instruction to the immune system: a fragment of the receptor, presented in a way that recruits killer T cells against any cell showing that fragment on its surface, which in practice means the endothelial cells of tumour vessels.
A receptor fragment, not a receptor blocker
The nine residues are copied from positions 169 to 177 of human VEGFR2 (PubChem CID 25210976). They carry no signalling function and do not compete with VEGF; their only job is to be recognised.
Fits one tissue type
The fragment is displayed by HLA-A*24:02, so only people with that HLA type can present it to T cells. Trials screened for it before enrolment (PMIDs 22957712, 22842485), so the approach could only ever reach the part of the population that carries it.
Trains T cells against vessel lining
Repeated injection in oil adjuvant raised peptide-specific cytotoxic T cells in most patients across the trials: 61% in the pancreatic phase 1 and 82% in the gastric study (PMIDs 19930156, 22842485). The target cells are the endothelial cells of new tumour vessels, which carry VEGFR2 in quantity.
Measured effects on the vessel signal
After vaccination the amount of soluble VEGFR2 in blood fell significantly, and gene-expression patterns in blood cells shifted in T-cell and angiogenesis pathways (PMID 22957712). These are signs the vaccine engaged its target; they are not clinical benefit, and the randomised trial found none (PMID 25867139).
Published Research
Every study below was read from its PubMed abstract in November 2026, with the two trial reports that are open access read in full for their dosing details. The literature on this peptide is small: one phase 1 trial in pancreatic cancer, one phase 1 trial across other solid tumours, one randomised phase 2/3 trial, one single-arm phase 2 trial in biliary tract cancer, and one trial of a two-peptide vaccine that included it. Papers about other VEGFR2 vaccine peptides, and the later Japanese trials of VEGFR peptide mixtures whose abstracts do not say which VEGFR2 peptide they used, are listed under References instead.
Phase 1 with gemcitabine in advanced pancreatic cancer
Patients with metastatic or unresectable pancreatic cancer received gemcitabine at 1,000 mg/m2 on days 1, 8 and 15 of a 28-day cycle, plus a weekly injection of the peptide at 0.5, 1 or 2 mg in cohorts of six. Among the 18 who completed at least one course, no adverse event of grade 4 or worse was attributed to the treatment, 15 (83%) reacted at the injection site, and peptide-specific cytotoxic T cells appeared in 11 (61%). Two-thirds had disease control and median overall survival was 8.7 months. The authors judged 2 mg or more the dose to carry forward on immunological grounds. Registered as NCT00622622.
The same phase 1 trial reported in Japanese, with the dose rationale
A Japanese-language account of the pancreatic phase 1 trial from the same group, written as the randomised trial was being launched. It sets out why VEGFR2 was chosen as a target: the receptor is abundant on newly formed tumour vessels and largely absent from normal ones, and attacking the vessels rather than the tumour cells avoids the escape routes cancer cells use to hide from immune attack. It repeats the trial's findings, gives 2 mg as the dose the immunology favoured, and records that the randomised phase 2/3 trial opened in January 2009. No new patient data.
Phase 1 in advanced solid tumours: no dose limit reached
Ten patients with refractory solid tumours, all positive for HLA-A*24:02, received the peptide alone under the skin weekly at 0.5, 1 or 2 mg on a 28-day cycle. No grade 3 or worse event occurred and no maximum tolerated dose was found. Five patients had grade 1 or 2 injection-site reactions, the commonest event; at the 1 mg level one patient had grade 1 proteinuria and another grade 1 proteinuria with raised blood pressure, the kind of effect expected when VEGF signalling is interfered with. Soluble VEGFR2 in blood fell significantly after vaccination, and gene-expression analysis of blood cells showed changes in T-cell and angiogenesis pathways, which the authors read as evidence the vaccine was biologically active. Registered as UMIN000008336.
PEGASUS-PC: the randomised phase 2/3 trial, no survival benefit
A multicentre, double-blind, placebo-controlled trial in locally advanced or metastatic pancreatic cancer, with patients assigned two to one to the peptide or placebo, each on top of gemcitabine. The analysis covered 153 patients, 100 on the vaccine and 53 on placebo. Overall survival, the primary endpoint, did not differ: median 8.36 months against 8.54 months, hazard ratio 0.87 (95% CI 0.486-1.557), with a statistical test chosen in advance to allow for the delayed effect immunotherapy might have. Side effects were mostly those of gemcitabine and broadly similar in the two arms, with more low-grade fever and raised liver enzymes on the vaccine; no death was attributed to the protocol. Severe injection-site reactions, meaning ulceration or erosion, occurred only in the vaccinated arm, and in that subgroup median survival was 15.67 months against 8.28 months for vaccinated patients without them. The trial was funded by the companies developing the peptide and registered as UMIN000001664.
Single-arm phase 2 in biliary tract cancer
Fifty-four patients with unresectable or recurrent biliary tract cancer received weekly gemcitabine for three weeks in four, with the peptide weekly throughout, and their survival was compared with historical figures rather than a control group. Median overall survival was 10.1 months and 44.4% were alive at a year, both better than the historical comparison. Tumours shrank enough to count as a response in 18.5%, and every responder had reacted at the injection site; among the 64.8% with such reactions median survival was 14.8 months against 5.7 months without. Serious adverse reactions occurred in five patients (9%) with no treatment-related deaths. Without randomisation the survival figure cannot be credited to the vaccine, and the authors' own conclusion was that the next step would be to work out which patients, if any, benefit. Registered as UMIN000002500.
Given with a second peptide and chemotherapy in gastric cancer
Twenty-two patients with advanced or recurrent stomach cancer, all HLA-A*24:02 positive, were vaccinated with this peptide together with a second one from VEGFR1 while receiving S-1 and cisplatin. Because every patient had both peptides, nothing here separates one from the other, but the immune readout for this peptide is its own: specific cytotoxic T cells were raised in 18 of 22 (82%) even under chemotherapy, and the patients who mounted that response lived longer and took longer to progress than those who did not (p = 0.028 and p = 0.006). Twelve patients (55%) had a partial response and the rest stable disease after two cycles; median time to progression was 9.6 months and median overall survival 14.2 months. The only effect attributed to the vaccine was inflammation where it was injected, in six patients.
Dosing Data
Every amount below was given inside a clinical trial, by injection under the skin, to patients selected for the HLA-A*24:02 tissue type. There is no approved product and no approved dose. The randomised trial that used the highest of these amounts found no survival benefit, so these figures record what was tried, not what works. One wrinkle in the randomised trial's report: its treatment section gives 2.0 mg per weekly injection, while its drug-preparation paragraph describes 1.0 mg dissolved in 1.0 mL of saline and mixed with an equal volume of adjuvant. The table uses the treatment section's figure, which matches the dose the phase 1 trials favoured.
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 label and no published test that says what forms or vial sizes Elpamotide is sold in. A vial's own label is a seller's claim, not a source.
Mixing a vial: a worked example
An arithmetic example, not a recommendation: a 5 mg vial mixed with 2 mL of bacteriostatic water holds 2,500 mcg per mL, so every 10 units on a U-100 insulin syringe hold 250 mcg. 2 mg, the “Study: PEGASUS-PC phase 2/3, pancreatic cancer” row is 80.0 units (0.800 mL). If your vial or water differ, the numbers change: use the reconstitution calculator.
Source: dose: Used in human trials, PMID 25867139 (Dosing Data below); vial and water: the calculator's default example, not a vial size we have a source for.
Storage before and after mixing
Unknown: no label or published stability study on file says how to store Elpamotide, before or after mixing. The mixing guide sets out the general rules, with their sources: keep a mixed vial in the fridge, and use it promptly, as the bacteriostatic water label says of any drug dissolved in it. The 28 days often quoted is the limit for an opened multiple-dose vial from a manufacturer, an outer limit set for sterility, not a time a mixed solution has been shown to keep. Nobody has published how long Elpamotide stays intact once mixed.
How it is taken
As it was given in human studies: Subcutaneous, as a water-in-oil emulsion with Montanide ISA51 VG (Once a week; Study: PEGASUS-PC phase 2/3, pancreatic cancer); Subcutaneous, with weekly gemcitabine (Once a week; Study: phase 2, biliary tract cancer); Subcutaneous (Once a week; Study: phase 1 dose escalation with gemcitabine); Subcutaneous, peptide alone (Once a week; Study: phase 1 in advanced solid tumours).
For injection technique, sites and needle disposal, see the mixing guide.
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: a half-life of Not reported: a depot vaccine in oil adjuvant, judged by the T cells it raises rather than by blood levels. After about five half-lives almost none is left.
How long the doses were given: Study: PEGASUS-PC phase 2/3, pancreatic cancer: Until the disease progressed; Study: phase 2, biliary tract cancer: Four injections per four-week course; Study: phase 1 dose escalation with gemcitabine: 28-day cycles, six patients per dose.
When effects appear: unknown; no source on this page gives a time to effect for Elpamotide. Results reported in the studies are under Published Research.
Source: half-life: PMID 22957712; 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: Reactions where the injection went in, in 83% of patients in the pancreatic phase 1 trial (PMID 19930156); Injection-site ulceration or erosion in a minority of vaccinated patients in the randomised trial, and in no one on placebo (PMID 25867139); Grade 1 or 2 injection-site reactions as the commonest event in the solid-tumour phase 1 trial, with no grade 3 or worse event at any dose (PMID 22957712); Grade 1 protein in the urine, in one case with raised blood pressure, at the 1 mg dose level: the effects expected when VEGF signalling is disturbed (PMID 22957712); More low-grade fever and raised liver enzymes than placebo in the randomised trial, on a background of gemcitabine toxicity that dominated both arms (PMID 25867139); Serious adverse reactions in five of 54 patients (9%) in the biliary tract trial, with no treatment-related deaths (PMID 25502982). Full list and cautions ↓
When to stop or get help: unknown; no label or trial on file sets rules for stopping Elpamotide. Treat a severe or unexpected reaction as a reason to stop and see a doctor.
Source: the Side Effects section below (“From the trials above”).
Interactions
Unknown: a PubMed search for human interaction studies of Elpamotide (reviewed 2026-11-04) 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 Elpamotide 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 Elpamotide's expected mass, 1,073.2 Da, from this entry's molecular data. Trust & Verification explains what independent testing can and cannot show.
Legal status
US: Not FDA Approved (Never approved: Drugs@FDA and the openFDA label endpoint hold no record for elpamotide (searched November 4, 2026), and ChEMBL records a highest clinical phase of 2 (CHEMBL2108295)). 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 trials above. All participants had advanced cancer and were receiving chemotherapy in most of the studies, so general symptoms are hard to attribute to the vaccine; local reactions are the exception.
Contraindications & Cautions
There is no label, so there are no official contraindications. What follows comes from how the peptide was studied.
Legal Status
Elpamotide is an investigational cancer vaccine that was developed in Japan and never approved anywhere.
Frequently Asked Questions
?What is elpamotide?
A synthetic peptide nine amino acids long, copied from part of VEGFR2, the receptor that growing blood vessels use to read VEGF. It was injected under the skin as a cancer vaccine so that T cells would attack the lining of tumour blood vessels. It is also called VEGFR2-169 and OTS-102.
?Does it work?
On the test that matters, no. In a randomised, placebo-controlled trial of 153 patients with advanced pancreatic cancer, adding it to gemcitabine left median survival unchanged, about eight and a half months in both arms (PMID 25867139). Earlier and smaller studies were encouraging, which is why the larger trial was done.
?Why did only people with one tissue type get it?
Because a T cell can only see a peptide that is held up by an HLA molecule, and this peptide fits HLA-A*24:02. In anyone without that HLA type the injected peptide has nothing to sit in, so the trials tested for it before enrolling patients (PMID 22957712).
?What was the injection-site finding about?
Across the trials, patients whose injection sites reacted strongly lived longer than those whose did not, and in the randomised trial severe local reactions happened only among the vaccinated (PMIDs 25502982, 25867139). It is a comparison inside a treated group, so it may just identify people with a more responsive immune system or a better general state. It is a hypothesis, not a result.
?Is it like the antibody drugs that block VEGF?
Only in its target. Antibody drugs against VEGF or its receptor block the signal directly, and the blocking stops when the drug wears off. Elpamotide carries a fragment of the receptor to train T cells against the cells that display it, so any effect would come from the immune response rather than from the peptide itself (PMID 22957712).
?Can anyone get it now?
No. It is not approved in any country, no trial of it is recruiting on ClinicalTrials.gov or UMIN, and it was only ever made as a trial product, weighed out and emulsified in an adjuvant by hospital staff. Anything sold under the name outside a trial has no established identity, purity or use.
References
- [clinical-trial] Miyazawa M, et al. "Phase I clinical trial using peptide vaccine for human vascular endothelial growth factor receptor 2 in combination with gemcitabine for patients with advanced pancreatic cancer." Cancer Sci, 2010;101(2):433-9. PMID: 19930156.
- [pubmed] Miyazawa M, et al. "[The development of a novel cancer vaccine using Peptide vaccine for patients with advanced pancreatic cancer]." Gan To Kagaku Ryoho, 2011;38(12):1903-5. PMID: 22202233.
- [clinical-trial] Okamoto I, et al. "Clinical phase I study of elpamotide, a peptide vaccine for vascular endothelial growth factor receptor 2, in patients with advanced solid tumors." Cancer Sci, 2012;103(12):2135-8. PMID: 22957712.
- [clinical-trial] Yamaue H, et al. "Randomized phase II/III clinical trial of elpamotide for patients with advanced pancreatic cancer: PEGASUS-PC Study." Cancer Sci, 2015;106(7):883-90. PMID: 25867139.
- [clinical-trial] Matsuyama M, et al. "Phase II trial of combination therapy of gemcitabine plus anti-angiogenic vaccination of elpamotide in patients with advanced or recurrent biliary tract cancer." Invest New Drugs, 2015;33(2):490-5. PMID: 25502982.
- [clinical-trial] Masuzawa T, et al. "Phase I/II study of S-1 plus cisplatin combined with peptide vaccines for human vascular endothelial growth factor receptor 1 and 2 in patients with advanced gastric cancer." Int J Oncol, 2012;41(4):1297-304. PMID: 22842485.
- [pubmed] Wada S, et al. "Rationale for antiangiogenic cancer therapy with vaccination using epitope peptides derived from human vascular endothelial growth factor receptor 2." Cancer Res, 2005;65(11):4939-46. PMID: 15930316.
- [pubmed] Tani M, et al. "[Multidisciplinary therapy for pancreatic cancer - clinical impact for preoperative therapy and peptide vaccine therapy]." Gan To Kagaku Ryoho, 2012;39(3):364-7. PMID: 22421762.
- [pubmed] Ottaiano A, et al. "Gemcitabine mono-therapy versus gemcitabine plus targeted therapy in advanced pancreatic cancer: a meta-analysis of randomized phase III trials." Acta Oncol, 2017;56(3):377-383. PMID: 28256961.
- [pubmed] Suzuki N, et al. "Phase II clinical trial of peptide cocktail therapy for patients with advanced pancreatic cancer: VENUS-PC study." Cancer Sci, 2017;108(1):73-80. PMID: 27783849.
- [pubmed] Yoshimaru Y, et al. "Randomized phase I/II study of vascular endothelial growth factor receptor peptide vaccines for patients with hepatocellular carcinoma." Hepatol Res, 2024;54(5):451-464. PMID: 38018304.
- [pubmed] Tamura R, et al. "Phase I/II Study of a Vascular Endothelial Growth Factor Receptor Vaccine in Patients With NF2-Related Schwannomatosis." J Clin Oncol, 2024;42(21):2578-2587. PMID: 38776485.
- [registry] ClinicalTrials.gov API v2, read November 4, 2026: three records use the peptide under the code VEGFR2-169, all in Japan and none with results posted. NCT00622622 ('Gemcitabine With Antiangiogenic Peptide Vaccine Therapy in Patients With Pancreatic Cancer', Wakayama Medical University, phase 1, 21 enrolled, November 2006 to February 2009, completed; escalating 0.5, 1.0 and 2.0 mg doses on days 1, 8, 15 and 22); NCT00655785 (Fukushima Medical University, phase 1/2, VEGFR1-1084 and VEGFR2-169 at 1 mg each with gemcitabine, 17 enrolled, completed March 2013); NCT00639925 (Fukushima Medical University, phase 1, the same two peptides with gemcitabine, 5 enrolled, status unknown). No record names elpamotide or OTS102. https://clinicaltrials.gov/study/NCT00622622
- [registry] UMIN Clinical Trials Registry, record R000002006 (UMIN000001664), read November 4, 2026: 'Phase2/3 Study of OTS102 in Combination With Gemcitabine in Patients With Unresectable Advanced Pancreatic Cancer and Recurrent Pancreatic Cancer (PEGASUS-PC Study)'; recruitment completed; the active group received OTS102 by subcutaneous injection on days 1, 8, 15 and 22 of each 28-day cycle with intravenous gemcitabine 1,000 mg/m2 on days 1, 8 and 15. https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000002006
- [other] PubChem CID 25210976 ('Elpamotide'; synonyms VEGFR2-169, 'VEGFR2-169 peptide vaccine', elpamotidum, Elpamotida; CAS 673478-49-4; UNII S68632MB2G): the VEGFR2-(169-177) peptide Arg-Phe-Val-Pro-Asp-Gly-Asn-Arg-Ile, molecular formula C47H76N16O13, molecular weight 1073.2. Read November 4, 2026. https://pubchem.ncbi.nlm.nih.gov/compound/25210976
- [other] ChEMBL molecule CHEMBL2108295 (ELPAMOTIDE), read November 4, 2026: molecule type Protein, sequence RFVPDGNRI, synonyms Elpamotide, Elpamotida, VEGFR2-169; highest clinical phase recorded 2. https://www.ebi.ac.uk/chembl/compound_report_card/CHEMBL2108295/
- [other] US FDA, Drugs@FDA and the drug label endpoint (openFDA), searched November 4, 2026: no application and no label record for elpamotide.
Sources & Citations
The six studies carded above and the six References-only papers were read from their PubMed records on November 4, 2026, and the two open-access trial reports were read in full for their dosing and trial details. Structure, formula and synonyms come from PubChem CID 25210976; development phase from ChEMBL; registration details from ClinicalTrials.gov and the UMIN Clinical Trials Registry; United States status from Drugs@FDA and the openFDA label endpoint, all read the same day. 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.