Moderna-merck Mrna Shot Cuts Melanoma Recurrence Risk 42%
WHO:
CNN - Merck and Moderna developed the experimental personalized mRNA cancer vaccine.
CNN - Dr. Michael Postow is chief of the melanoma service at Memorial Sloan Kettering Cancer Center.
STAT - Adam Feuerstein is a senior writer and biotech columnist; he covers drug development, business, Wall Street, and biotechnology, co-hosts the weekly biotech podcast *The Readout Loud*, and writes *Adam’s Biotech Scorecard*.
STAT - Andrew Joseph, a STAT colleague of Feuerstein, joined him to report from the European Society for Medical Oncology Congress.
WHAT:
The Washington Post - The vaccine reduced the risk of melanoma recurrence or death by almost half.
BBC - A study participant did not know whether he received the experimental vaccine or a placebo alongside immunotherapy.
The Washington Post - The vaccine is seeking federal approval.
NY Post - Moderna and Merck released the study results.
CNN - In a late-stage clinical trial involving melanoma patients, the experimental vaccine combined with the approved drug Keytruda reduced the risk of cancer recurrence after surgery or death by 42% compared with Keytruda alone.
CNN - Postow said: “This new vaccine is something that we’ve never really seen before in terms of the efficacy that it has demonstrated and the way that it works.”
CNN - The vaccine was described as potentially the first personalized mRNA cancer vaccine to succeed in a late-stage melanoma clinical trial.
CNN - Merck released the data early after reports that the results had been published online and then taken down.
STAT - Feuerstein’s newsletter said its coverage would provide updates from the ESMO Congress through the *ESMO in 30* newsletter.
WHERE:
CNN - The results were to be presented at a European Society for Medical Oncology meeting in Madrid.
STAT - Feuerstein reported from Madrid at the European Society for Medical Oncology Congress.
WHY:
CNN - The vaccine was tested with Keytruda to evaluate whether the combination could reduce the risk of melanoma returning or patients dying after surgery, compared with Keytruda alone.
HOW:
CNN - The vaccine is an experimental personalized mRNA treatment developed by Merck and Moderna and was evaluated in combination with Keytruda.
(UPDATED October 23, 2026 16:15 UTC)
Merck and Moderna say their experimental personalized mRNA vaccine, given with the immunotherapy drug Keytruda, cut the risk of melanoma returning or a patient dying by 42% compared with Keytruda alone. The late-stage trial involved people with melanoma after surgery, and the results suggest the approach could become the first personalized mRNA cancer vaccine to succeed in a late-stage melanoma trial. A participant said he did not know whether he had received the vaccine or a placebo alongside immunotherapy. The companies released the results ahead of their presentation at a European Society for Medical Oncology meeting in Madrid, after reports that the data had briefly appeared online and been taken down. The vaccine is seeking federal approval. Dr. Michael Postow, who leads melanoma care at Memorial Sloan Kettering Cancer Center, called the findings unprecedented in both efficacy and how the treatment works.
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(UPDATED October 23, 2026 15:20 UTC)
Merck and Moderna report that their experimental personalized mRNA cancer vaccine reduced the risk of melanoma returning or patients dying after surgery. In a late-stage trial, patients who received the vaccine alongside Keytruda had a 42 percent lower risk of recurrence or death than those given Keytruda alone. The companies released the results early after reports that the data had appeared online and then been taken down. The findings were due to be presented at the European Society for Medical Oncology meeting in Madrid. If approved, the vaccine could become the first personalized mRNA cancer vaccine to succeed in a late-stage melanoma trial. Dr. Michael Postow, who leads the melanoma service at Memorial Sloan Kettering Cancer Center, called the results unprecedented in their demonstrated effectiveness and approach. The vaccine is seeking federal approval.
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(UPDATED October 22, 2026 22:15 UTC)
An experimental personalized mRNA cancer vaccine developed by Merck and Moderna reduced the risk of melanoma returning or patients dying by 42% when combined with Keytruda, compared with Keytruda alone. The finding comes from a late-stage clinical trial involving melanoma patients who had undergone surgery. The results could mark the first success for a personalized mRNA cancer vaccine in a late-stage melanoma trial. Merck released the data early after reports that the results had been published online and then taken down. Dr. Michael Postow, chief of the melanoma service at Memorial Sloan Kettering Cancer Center, said the vaccine’s effectiveness and how it works are unlike anything seen before. The results were set to be presented at the European Society for Medical Oncology meeting in Madrid. STAT biotech writers Adam Feuerstein and Andrew Joseph reported from the congress, with further coverage planned through the ESMO in 30 newsletter.