Skin cancer vaccine cuts risk nearly in half
Archived — this story has rotated out of today’s deck. It is kept here in full.
The gist
Moderna and Merck's mRNA vaccine plus Keytruda cut melanoma recurrence or death risk by 42% in a late-stage trial.
The result is near a record for melanoma, but shares fell and approval is still pending.
Background
Moderna, a Cambridge, Mass. drugmaker, and Merck & Co. are testing intismeran autogene, an mRNA vaccine built on the technology used in coronavirus shots and designed to train the immune system on proteins unique to a patient's tumor. It is given with Merck's immunotherapy Keytruda to patients after surgery to remove melanoma lesions, a setting called adjuvant treatment. The companies reported the Phase 3 results early after screenshots leaked on social media, and the data were to be presented at the European Society for Medical Oncology Congress in Madrid.
How it unfolded
- 2026 -08Moderna and Merck said the vaccine-plus-Keytruda combination beat Keytruda alone in a late-stage trial, meeting its main goal at an early, pre-planned data check; Moderna's stock rose more than four-fold afterwards.
- Oct 22, 2026The companies announced full results: patients who got the vaccine after surgery were 42% less likely to have a recurrence or die within two years, and the risk of the cancer spreading fell 38%.
- Oct 22, 2026Screenshots of the findings leaked on social media, prompting ESMO to release the study details before the Madrid meeting; the companies lifted their embargo.
- Oct 22, 2026Shares fell on the news, with Moderna down nearly 25% and Merck around 1%.
Who’s saying what
- Official
- Moderna CEO Stephane Bancel called the data a new chapter in cancer treatment and said the companies are preparing to file for US approval, expecting a launch in 2027.
- Expert
- Robert Vonderheide of the American Association for Cancer Research said the results are on par with the field's biggest breakthroughs and that everyone is hopeful about a new way to treat melanoma.
- Analysts
- TD Cowen's Tyler Van Buren said the efficacy profile substantially clears the bar for a practice-changing dataset in adjuvant melanoma.
- Bears
- RBC's Trung Huynh said the data makes him less optimistic on pricing, since melanoma was supposed to be the best case, and William Blair's Myles Minter described a sell-the-news reaction.
Still unverified
Screenshots of the findings were leaked on social media before the Madrid meeting, prompting ESMO to release the study details early. Some are skeptical that the vaccine's success in melanoma, a cancer that responds well to immunotherapy, will extend to other cancers that respond less well.