Melanoma, the most dangerous of common skin cancers, has long carried the shadow of returning after surgery has seemingly removed it. In a trial led from Australia, researchers have now shown that a vaccine built uniquely for each patient, made with the same messenger RNA technology that carried the world through COVID-19, can lower that risk when added to standard immunotherapy. The result, reported on a Friday in late 2026, rests on two years of follow-up among more than 1,100 people, and its meaning will only fully unfold as those participants are watched over the years ahead.
Australian-led trial shows personalised mRNA melanoma vaccine cut recurrence risk by 42 per cent
Over 1,100 people with surgically removed high-risk melanoma took part in the trial, with the vaccine group showing fewer recurrences.
A vaccine built individually for each patient, using Nobel Prize-winning mRNA technology
Mark
Start with the number. Forty-two per cent. What does that actually mean for a patient?
Mimi
It's a reduction in the risk of melanoma returning at two years. The plainer figures are 82 per cent still recurrence-free with the vaccine, against 70 per cent on Keytruda alone.
Luke
Worth noting those are two different framings of the same result. The 42 per cent is relative; the twelve-point gap is the absolute difference. Both are in the report, but they feel very different.
Mark
And who was in the trial?
Mimi
More than 1100 people whose high-risk melanoma had been surgically removed. Everyone got Keytruda, and then half, effectively, were randomised to the vaccine or a placebo.
Luke
I'd be careful with 'half'. The source says randomly assigned, but doesn't give the split. I wouldn't assume it.
Mark
Why is Georgina Long's reaction so strong?
Mimi
She called it a foundational shift and compared it to a moon landing. She also said she isn't prone to exaggeration, which is her way of saying she means it.
Luke
That's an investigator describing her own trial, and the study was funded by Moderna and Merck, who also make the drug involved. It doesn't invalidate anything, but it's context for the language.
Mark
So what's still unknown?
Mimi
Longer-term outcomes. The trial is still tracking people, so we don't yet know how long the benefit lasts.
Luke
Right. Two years is the data we have. Side effects, regulatory approval and cost aren't covered in this report at all.
The Pulse
- A cancer that has already been cut away still threatens to come back, and more than 1,100 high-risk patients lived with that uncertainty.
- A personalised vaccine, intismeran, was layered onto Keytruda, shifting the familiar treatment path for people fighting relapse.
- Two years on, 82 percent of vaccine recipients remained cancer-free, against 70 percent of those given Keytruda alone.
- The 42 percent drop in recurrence has opened a new frontier, yet the question of how long the benefit lasts and whether regulators will adopt it is still unresolved.
Melanoma, the most dangerous of common skin cancers, has long carried the shadow of returning after surgery has seemingly removed it. In a trial led from Australia, researchers have now shown that a vaccine built uniquely for each patient, made with the same messenger RNA technology that carried the world through COVID-19, can lower that risk when added to standard immunotherapy. The result, reported on a Friday in late 2026, rests on two years of follow-up among more than 1,100 people, and its meaning will only fully unfold as those participants are watched over the years ahead.
On Friday, an Australian-led clinical trial reported what its researchers describe as a world-first vaccine against melanoma. The vaccine, called intismeran, is made individually for each patient, and it uses the same mRNA technology that powered the COVID-19 vaccines, now turned toward a very different purpose.
The study was led by Professor Georgina Long, medical director at the Melanoma Institute Australia. Long, a former Australian of the Year, is widely seen as the driving force behind the work. More than 1,100 people with high-risk melanoma, a cancer whose removal by surgery still leaves a real chance of return, took part. All of them received Keytruda, the standard follow-up immunotherapy, and were then randomly assigned either to add the tailor-made vaccine or to receive a placebo.
The headline is a 42 percent reduction in the risk of melanoma returning at two years for those who had the vaccine. In plain terms, 82 percent of the vaccine group were alive and free of recurrence at that point, compared with 70 percent of those on Keytruda alone. Long said she was overwhelmed, insisting she was not prone to exaggeration yet calling it a very big leap forward in cancer.
The trial is still running, and researchers continue to follow participants over the longer term. Whether the benefit endures, and whether regulators and health systems will bring the vaccine into wider use, remain open questions. The trial was funded by Moderna and Merck.
On Friday, an Australian-led clinical trial reported results for what it describes as a world-first vaccine against melanoma, a skin cancer. The vaccine, called intismeran, is built individually for each patient who receives it.
The study was led by Professor Georgina Long, medical director at the Melanoma Institute Australia, which is affiliated with the University of Sydney. Long is a former Australian of the Year. She shared the 2024 award with the late Professor Richard Scolyer, a pioneering cancer scientist and her colleague. The source describes her as a driving force behind the treatment.
The trial enrolled more than 1100 people with high-risk melanoma that had been surgically removed. Every participant received the standard follow-up therapy, Merck's immunotherapy drug Keytruda. Participants were then randomly assigned either to receive tailor-made vaccine doses in addition, or to receive a placebo. Moderna and Merck funded the study.
The vaccine uses mRNA, the same Nobel Prize-winning technology behind the COVID-19 vaccines. Here it is applied differently, as a treatment customised for each patient taking part.
The headline result is a 42 per cent reduction in the risk of melanoma returning two years later among those who had the vaccine on top of standard treatment. In absolute terms, 82 per cent of people in the vaccine group were alive and living without a recurrence at two years. In the group that received Keytruda alone, the figure was 70 per cent.
Long told The Sydney Morning Herald she was overwhelmed by the findings. "I'm not one prone to exaggeration, but this really is a very, very big leap forward in cancer," she said. She went on to reach for the familiar comparisons: a landmark moment, a moon landing, a first flight. In her words, it is a foundational shift.
The results come from a two-year follow-up, and the trial is not finished. Researchers are continuing to track participants' longer-term outcomes. How durable the benefit proves to be, and whether regulators and health systems take the vaccine up more widely, are questions the current reporting does not answer. The source material is a wire-based report and does not detail the trial's full data or any side effects.
Notable Quotes
I'm not one prone to exaggeration, but this really is a very, very big leap forward in cancer.— Professor Georgina Long, Melanoma Institute Australia
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