mRNA melanoma vaccine cuts recurrence
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The gist
Moderna and Merck's personalized mRNA vaccine cut melanoma death or recurrence risk by 42% in a late-stage trial.
It is the first such win for a vaccine tailored to each patient's tumor.
Background
Moderna and Merck are pharmaceutical partners that developed the vaccine, called intismeran, using the same mRNA technology behind COVID-19 vaccines. The Phase 3 trial enrolled 1,137 patients with stage IIB–IV melanoma that had been surgically removed, randomized 2-1 to the vaccine plus standard treatment (Merck's Keytruda) or standard treatment alone. It is the first trial to show a vaccine based on mutations unique to each patient's tumor, combined with an immune-boosting drug, can keep the disease at bay. Results drew attention partly because they were released early, after an oncology news site broke the embargo ahead of a scheduled presentation in Madrid.
How it unfolded
- 2024Tony Hout joined the vaccine trial at MD Anderson after a spot on his ear that had been bleeding intermittently and wouldn't fully heal; surgery revealed it had started to spread.
- Aug 2026Moderna and Merck announced the vaccine had succeeded in the trial but did not provide details.
- Oct 22, 2026The companies announced the personalized mRNA vaccine reduced the risk of death or recurrence by 42% versus standard treatment, releasing top-line results after an oncology news site broke the embargo.
- Oct 23, 2026MedPage Today reported the results were released early after an online data leak; the data had been scheduled for presentation Saturday at ESMO in Madrid.
- Oct 24, 2026Data scheduled for presentation by Georgina Long at the European Society for Medical Oncology congress in Madrid.
Who’s saying what
- Official
- Moderna CEO Stéphane Bancel said the results mark a defining moment for the belief that mRNA could enable treatments uniquely matched to each patient's tumor.
- Expert
- Georgina Long of the University of Sydney said the findings could make a foundational shift in treating earlier-stage melanoma in the adjuvant setting.
- Caution
- Alan Melcher of the Institute of Cancer Research said the trial gives stronger evidence a personalized cancer vaccine can help patients, but the approach can't be assumed to work across all cancers and longer follow-up is needed on overall survival.
- Analysts
- Before the meeting, Wall Street investors were looking for the combination to cut recurrence risk by 40% or more.
Still unverified
The results were released early after an online data leak, with an oncology news site reported to have broken the embargo; the companies then issued a full release ahead of the scheduled scientific presentation.