IO102-IO103 dosage and evidence
Written by Aaron CuhaReviewed Sep 2026
The short answer
IO102-IO103 is a cancer vaccine made of two peptides, given as a shot along with the immune drug pembrolizumab for advanced melanoma.
Evidence grade for IO102-IO103: Moderate. The rule: at least one finished study in people, and at least 100 people who took it. The sum on this page: 3 completed trials, 470 people given it. A grade counts how much has been done to people, not whether it works.
- People given it
- 470
- Human studies
- 3
- Found nothing
- 0
Dose
No human dose established
Amounts that were given in studies sit in Human evidence on this page. None of them is a personal dose.
3 completed trials, 470 people given it
3 effects reported, 2 unwanted, 1 wanted, by people using it, not a trial
Goal pages: Ageing and longevity, Immune system and inflammation
In plain English
In plain English, from Aaron
This is how I would explain it to a friend. The evidence, with the numbers, is further down the page.
IO102-IO103 is a cancer vaccine made of two peptides. It trains the immune system to attack the cells that shield a tumour. It is given as a shot with an immune drug, pembrolizumab, for advanced melanoma. It is not approved anywhere.
What people take it for
- Helping immune drugs work better against advanced melanoma.
- Keeping melanoma from growing for longer.
What studies in people showed
The big trial had 407 people with advanced melanoma. Half got the vaccine plus pembrolizumab. Half got pembrolizumab alone. The typical time before the cancer got worse was 19.4 months with the vaccine and 11.0 months without. That sounds large, but it just missed the bar the trial set in advance. So it does not count as proven. Serious side effects were about the same in both groups. An earlier study of 48 people looked better, but it had no one to compare against. A head and neck cancer study was stopped after 17 people because it missed its goal.
What people report
Reports, not study results
The good
- Serious drug related side effects were about the same with or without the vaccine, 14.5 against 15.6 percent.
The bad
- 56 percent had a reaction where the shot went in, mostly mild.
- The big trial just missed its own bar, so the benefit is not proven.
Where these come from: From the trials on this page. It is a hospital cancer treatment, so there are no user reports.
My bottom line
My opinion: this is a real hospital cancer drug with a near miss, not something anyone buys. If you or someone you love has melanoma, ask the cancer team about trials. That is the only way in.
An opinion, not a finding. I am a coach, not a doctor.
What it has been measured to do
Measured in people
Goals IO102-IO103 has been tested for in people, biggest studies first. We count only what the studies on this page say, so the real numbers may be higher.
- Living longer407 people · 1 study
- Cancer and tumoursno headcount stated · 1 study
34 of the 36 indexed goals have no study of any kind behind IO102-IO103
No study in people, animals or cells on this page reports a result for these. That does not prove IO102-IO103 does nothing for them. It does mean anything you have heard about IO102-IO103 and one of these did not come from a study cited here.
Show full evidence
What is IO102-IO103?
IO102-IO103 is a cancer vaccine made of two peptides, given as a shot along with the immune drug pembrolizumab for advanced melanoma. In a 407 person final-stage trial, the typical time before the cancer got worse was 19.4 months with the vaccine, against 11.0 months without it. That gap just missed the bar the trial set in advance, so the trial counts as a miss.
Most cancer vaccines try to train immune cells to attack the tumour. IO102-IO103 aims somewhere else. Its two peptides come from IDO1 and PD-L1. These are proteins made by the cells that shield a tumour from the immune system. So the immune cells it trains go after the tumour's defences, not the tumour itself. It is given as a shot of 85 mcg of each peptide, alongside a drug that blocks PD-1, an immune brake. IO Biotech developed it. The science and first study came from the melanoma team at Copenhagen University Hospital. Their lead researcher founded the company.
The biggest study is the final-stage trial called IOB-013 or KEYNOTE-D18. It took 407 people with advanced melanoma who had not been treated yet. They got the vaccine plus pembrolizumab, or pembrolizumab alone. Everyone knew which, but scans were read by outside reviewers who did not. The typical time before the cancer got worse was 19.4 months with the vaccine and 11.0 months without. The trial had set a bar in advance for calling that gap real, and it fell just short. The authors say so. The vaccine group did better in most smaller groups too. The biggest gap was in tumours that make no PD-L1, at 16.6 months against 3.0. But those smaller group looks were side questions. Serious drug related side effects were about the same, 14.5 against 15.6 percent. All serious problems were also about the same, 32.0 against 32.3 percent. 56 percent of vaccinated people had a reaction where the shot went in, mostly mild.
The earlier study, MM1636, gave 48 people with melanoma that had spread the vaccine with nivolumab. Everyone got the vaccine. After five years of follow up, the typical time before the cancer got worse was 25.5 months. That number drew attention, but there was no comparison group behind it. In head and neck cancer, a university hospital study in Brussels was stopped after 17 people because it missed its main goal. A 15 person study in the same cancer found the hoped-for immune response in one patient.
IO102-IO103 is not approved anywhere. What happens next depends on whether regulators, or another trial, will act on a result that just missed.
How does IO102-IO103 work?
In people, the vaccine raises immune cells in the blood that recognise the IDO1 and PD-L1 peptides. That was measured with a blood test in the earlier melanoma study and in a head and neck study. A 2025 paper reports that people who did well had rises in three immune signals in the blood, called CCL3, CCL4 and TNF-alpha. Those rises were not seen in a matched group given the PD-1 drug alone. The next step would be the immune cells killing or changing the tumour's shield cells. Lab tests on patient samples back that up. So do gene readouts of removed head and neck tumours, which showed more swelling related gene activity in vaccinated patients. The reason to pair it with a PD-1 drug is simple. The PD-1 drug takes the brake off immune cells already there. The vaccine removes the cells pressing the brake. Each step has been seen in patients. Whether the steps add up to longer survival is what the final-stage trial was built to test.
What have studies in people found about IO102-IO103?
A lot for a test vaccine. There is a published 407 person final-stage trial, a 48 person study with no comparison group followed for five years, and two small head and neck cancer studies. The final-stage trial missed its bar by a hair. Its result fits a real benefit and also fits no benefit at all.
- Final-stage trial IOB-013 / KEYNOTE-D18 (2026): 407 people with advanced melanoma, vaccine plus pembrolizumab against pembrolizumab alone. The typical time before the cancer got worse was 19.4 months against 11.0. That just missed the bar set in advance. Side looks at smaller groups favoured the vaccine, most in tumours with no PD-L1. Side effects were no worse apart from shot site reactions in 56 percent. The maker paid.
- MM1636 (2025 five year report): 48 people, everyone got the vaccine plus nivolumab. The typical time before the cancer got worse was 25.5 months. No comparison group. A hospital study with company people among the authors.
- NCT04445064: a university study in head and neck cancer, 17 people, stopped because it missed its main goal.
- HN1901: 15 people with head and neck cancer. The hoped-for immune response showed up in 1. Tumours shrank in 2 of the 5 given IO103. Safe over three weeks.
- Whether people lived longer overall has not been reported from the final-stage trial.
What this does not tell you: The final-stage result fits a real but modest benefit, and it also fits no benefit. The trial's own rule says it did not prove one. The smaller group results, including the no PD-L1 result, are side questions. Each would need its own trial. Everyone knew which treatment they got. That can shift when a scan gets called as worse, even with outside reviewers reading the scans. The trial measured when cancer got worse, not how long people lived. The 25.5 month figure from MM1636 comes from 48 people with no comparison group. It cannot be set next to the final-stage trial groups. Nothing here applies to any cancer besides melanoma. The head and neck data are one failed study and one 15 person study that only describes what happened.
The state of the research
IO102-IO103 is rare among test peptides. It has a finished, published trial big enough to answer the question. And that trial gave the hardest kind of result to act on. If real, the gap between 19.4 and 11.0 months would matter a lot to people with melanoma. But the trial did not clear its own bar, so it did not show the gap is real. The authors say this plainly at the top of the paper, which is to their credit. Then they describe the combination as showing potential benefit, which is the company's interest speaking. IO Biotech paid for the trial, and the authors list many industry ties. The company's founder and staff also wrote the MM1636 paper. Its 25.5 month figure set the hopes for the final-stage trial.
What the record lacks is an outside repeat, or data on how long people lived. Regulators sometimes accept a near miss with good backing data, and sometimes ask for another trial. Either path is fair on these numbers, and this page does not pick one. Tumours with no PD-L1 are where PD-1 drugs alone do worst. That is also where the vaccine's side result looked best. It is the obvious group for a follow up trial. The failed head and neck study is a reminder that the idea does not carry over by itself from one cancer to another. Nobody sells this to the public. It is a hospital cancer treatment that has never existed outside trials.
The evidence, in charts
Fig. 1a · how many people
518people, across 4 studies in people cited here
| Study | People | Share |
|---|---|---|
| Annals of Oncology 2026 | 407 | 79% |
| NCT03047928, Nature Communications 2025 | 48 | 9% |
| NCT03047928, ClinicalTrials.gov, Copenhagen University Hospital 2018 | 48 | 9% |
| European Archives of Oto-Rhino-Laryngology 2025 | 15 | 3% |
One study holds 79% of these people, so the total rests more on one study than its size suggests. Counts are the number of people each study on this page says it signed up. That includes studies that only watched people and gave nobody the compound. 2 more studies in people give no headcount and are not counted here. Studies still signing people up are left out, and only studies cited on this page are counted.
Fig. 1b · evidence mix
All 6 sources here are studies in people.
- Study in people · done in people6100%
Counted from the list of sources on this page. It counts only what we cite, so there may be more studies out there. A review counts once, however many studies it sums up.
Fig. 2 · evidence over time
The studies cover 5 different years, 2018 to 2026, counted from the list of sources on this page.
Fig. 3 · legal status at a glance
US
Not approved
UK
Not approved
AU
Not approved
CA
Not approved
Not approved in any of the four countries shown. This is what the law says, not a verdict on the science. See Legal status below for the full text and any notes.
Fig. 4 · how much does what
Nobody has tested different amounts in people
This chart would show how the effect changes as the amount goes up. For this compound, nobody has measured that in people. So we leave it empty. We will not borrow an animal chart and pretend it works the same in people.
Fig. 5 · what the molecule is
- Kind of compound
- Peptide
- Molecule weight
- Not on file
- Half-life
- None on file
- Chain length
- None on file
No amino acid sequence is on file for IO102-IO103, so none is drawn rather than guessed from a name.
The studies we cite
- Study in people2026IO102-IO103 immune-modulatory cancer vaccine and pembrolizumab in melanoma
The vaccine looked like it was helping, and the trial still counts as a failure. Four hundred and seven people with advanced melanoma got a standard immune drug, half of them with the vaccine added, and everyone knew which. Cancer took much longer to worsen in the vaccine group, close to nineteen months against eleven. The gap fell just short of the bar the trial had set in advance, so the result does not stand. More than half had a reaction where the shot went in. The maker paid.
Open label phase 3, 407 patients with untreated advanced melanoma randomised 1:1 to IO102-IO103 (85 mcg each) plus pembrolizumab or pembrolizumab alone for up to 2 years. Median progression free survival 19.4 versus 11.0 months, HR 0.77 (95% CI 0.58 to 1.00), p = 0.0558; the prespecified threshold of p at most 0.045 was missed. Grade 3 or worse treatment related adverse events 14.5 versus 15.6 percent; injection site reactions in 56 percent. Sponsored by IO Biotech; the authors declare extensive industry relationships.
- Study in people2022IO102-IO103 in Combination With Pembrolizumab Versus Pembrolizumab Alone in Advanced Melanoma, IOB-013 / KN-D18 (NCT05155254)
This is the registry entry for the melanoma trial reported above. It confirms four hundred and seven people enrolled and that the main measurement point passed in May 2025. The study is listed as still running but no longer taking new people. The entry itself carries no results, which is what a registry record looks like. The maker paid for it.
Registry record for the phase 3: 407 enrolled, primary completion 30 May 2025, status active, not recruiting, as of September 2026. Sponsor funded.
- Study in people2025Five-year clinical outcome and immune biomarkers of durable response from the MM1636 trial on IDO/PD-L1 vaccination and PD-1 blockade in first line metastatic melanoma
Everyone in this study got the vaccine, so the striking number has nothing to stand against. Forty eight people whose melanoma had spread were given the vaccine alongside a standard immune drug, then followed for five years. Cancer stayed stable for about two years on average. People whose immune signals rose tended to do better for longer. There was no group that went without the vaccine, so nobody can say what it added. The authors include the maker's founder and staff.
Single arm phase 1/2 (NCT03047928), 48 patients with metastatic melanoma given the vaccine with nivolumab. Median progression free survival 25.5 months at five year follow up. Rises in serum CCL3, CCL4 and TNF-alpha tracked long progression free survival and were not seen in a matched anti-PD-1 monotherapy cohort. No randomised comparator. Investigator initiated at Copenhagen University Hospital; authors include IO Biotech's founder and employees.
- Study in people2025Translational investigations in the HN1901 phase II window-of-opportunity study of IDO1 (IO102) and PD-L1 (IO103) peptide vaccines in squamous cell carcinoma of the head and neck
Fifteen people is too few to learn anything about whether this works. They had head and neck cancer and were given the vaccine, or nothing, for three weeks before surgery. One person showed the immune response the vaccine is meant to produce. Two had tumours shrink. Nothing serious was blamed on the vaccine. The study was built to describe what happened, not to answer a question. Read it as a first look and nothing more.
15 patients: 10 randomised to IO102 or no preoperative treatment, 5 more given IO103, for three weeks before curative surgery. A peptide specific T cell response was detected in one IO103 vaccinated patient; two IO103 patients had tumour shrinkage. No grade 3 or 4 events attributed to the vaccine. Very small, largely descriptive.
- Study in people2020Activity and Safety of Peptide-based Immunotherapy in Patients With Squamous Cell Carcinoma of the Head and Neck (NCT04445064)
This trial was stopped because the vaccine did not do what it was meant to. Seventeen people with head and neck cancer had enrolled. The sponsor recorded the reason for stopping as the study failing to hit its target. A university hospital ran it, not the maker. No results have been published. The record shows a trial halted for lack of effect, which is a result in itself.
Academic phase 2 in head and neck cancer, 17 enrolled, terminated. Reason recorded by the sponsor: unmet primary endpoint.
- Study in people2018Combination Therapy With Nivolumab and PD-L1/IDO Peptide Vaccine to Patients With Metastatic Melanoma, MM1636 (NCT03047928)
This is the registry entry for the forty eight person melanoma study described above. It confirms the trial finished at the end of 2022 and that results were posted in February 2025. A hospital researcher sponsored it rather than the company. The entry reports no comparison group, because the study had none.
Phase 1/2, 48 enrolled, completed December 2022, results posted February 2025. Investigator sponsored (Inge Marie Svane).
Where to buy IO102-IO103
No seller we track lists IO102-IO103 yet. We read sellers’ public product lists every week, and this section fills in as soon as one does. Every seller, graded
Common questions
Has IO102-IO103 been tested in people?
Yes. 470 people given it across 3 completed trials cited here, 0 of which found nothing. IO102-IO103 is a cancer vaccine made of two peptides, given as a shot along with the immune drug pembrolizumab for advanced melanoma.
What is the IO102-IO103 dosage?
No human dose established. Amounts that were given in studies sit in Human evidence on this page. None of them is a personal dose. 3 completed trials, 470 people given it
Is IO102-IO103 FDA-approved?
Not FDA approved. A final-stage study in advanced melanoma, given as the first treatment (407 people), missed its main goal. It came close but fell just short of the bar the study had set (Annals of Oncology, 2026).
Did the IO102-IO103 phase 3 succeed?
No, by its own rule. In 407 people, the typical time before the cancer got worse was 19.4 months with the vaccine plus pembrolizumab. It was 11.0 months with pembrolizumab alone. The trial had set a bar in advance for calling that gap real, and the result fell just short. The authors say the bar was missed.
Was the vaccine toxic?
Not beyond the shot site, on the published numbers. Serious drug related side effects were 14.5 percent with the vaccine and 15.6 percent without. All serious problems were 32.0 against 32.3 percent. 56 percent of vaccinated people had a reaction where the shot went in, mostly mild.
What about the PD-L1 negative result?
In people whose tumours made no PD-L1, the typical time before the cancer got worse was 16.6 months with the vaccine and 3.0 months without. That is a side look at a smaller group, from a trial that missed its main goal. It would need a trial of its own to prove it.
Is IO102-IO103 approved or available?
No. It is a test drug. It has only ever been given in hospital trials alongside a PD-1 drug, and it does not exist outside them.