August 19, 2026, Moderna and Merck’s personalized mRNA cancer vaccine had a positive outcome for phase 3 trial results. Though it’s not fully approved or officially out the market, it is highly possible that cancer vaccines will soon come out. The vaccine is called ‘intismeran autogene’. The trial focused on patients with high risk melanoma ( skin cancer ) whose tumors had already been surgically removed. The vaccine was said to be used together with Keytruda which is an existing cancer immunotherapy.
The vaccine is a personalized treatment. When a patient’s tumor is removed, scientists analyze the tumor’s DNA and identify mutations that are unique to that cancer. They select 34 tumor-specific mutations which are called neoantigens. A personalized mRNA vaccine is created based on these mutations. Because the mRNA teaches the patient’s immune system to recognize those cancer-specific markers which can identify and attack the remaining cancer cell without damaging other cells that benefit our body. So the vaccine basically gives the immune system a mark to identify the patient’s cancer cells. The phase 3 trial included more than 1,100 patients. Patients receiving both the vaccine and keytruda had lower recurrence free survival rate ( possibility of cancer to form again ) and distant metastasis free survival rate ( possibility of cancer to spread through to body) than patients just receiving Keytruda alone. Moderna announced that phase 3 trial met its major endpoints, although detailed data were still awaiting presentation.
Cancer is one of the most difficult diseases to treat because tumors can have different mutations even among patients who have the same type of cancer. Personalized vaccines allow treatment to be designed for specific patient’s tumors. It is significant because it’s the first mRNA based cancer vaccine to have a positive outcome in phase 3 trial.
Moderna and Merck have developed a personalized mRNA cancer vaccine that uses mutations from an individual patient’s tumor to train the immune system to recognize and attack cancer cells. Phase 3 trials showed a possibility of preventing melanoma from spreading or returning cancer cells and helping people who suffer from those.
By. Madison Yi
Citations
https://www.nature.com/articles/d41586-026-02612-3
https://edition.cnn.com/2026/08/21/health/mrna-cancer-vaccines-wave
https://trials.modernatx.com/study/?id=mRNA-4157-P201