In August 2026, Merck and Moderna announced that the cancer vaccine, intismeran autogene, combined with the standard immunotherapy drug Keytruda, reduced melanoma recurrence and distant metastasis in high-risk melanoma patients compared with Keytruda alone. This is an important milestone for the mRNA-based cancer vaccine field, since this clinical trial (INTerpath-001) is the first large, late-stage, randomized trial to report positive results for an mRNA-based cancer therapy. Just as importantly, it is the first positive phase 3 trial of an individualized neoantigen therapy.
It is a treatment vaccine, not a prevention vaccine
Most people think of prevention rather than therapy when they hear “vaccine,” because they are most familiar with vaccines against infectious agents that prevent disease from occurring, like COVID, influenza, polio, etc. In cancer, HPV (human papilloma virus) vaccine is a highly successful example of a prevention vaccine; it prevents HPV infections, which can lead to cervical and other cancers.
Intismeran autogene is different. It is a treatment used in the adjuvant setting. It is given after melanoma has been surgically removed (resected), to reduce the risk of residual cancer cells causing the disease to come back or spread.
It is a personalized neoantigen vaccine.
Neoantigens are abnormal protein fragments produced by mutations in the tumor. Because these are not found in normal cells, they can help the immune system identify cancer cells. The vaccine carries mRNA containing the instructions for making the neoantigens. Once injected, the body generates the neoantigens, stimulating the immune system to recognize and attack the tumor cells displaying them. The mRNA technology used in the vaccine is the same basic technology used in Moderna’s COVID-19 vaccine. But the goal is different, instead of training the immune system to recognize a pathogen before infection occurs, the vaccine trains it to identify tumor-specific markers. Since each patient’s tumor has a unique neoantigen repertoire, each vaccine is custom made.
Immunoprevention as a potential next frontier
The intismeran autogene vaccine strategy is designed for people who have already developed cancer and undergone surgery. The next potential frontier is cancer immunoprevention – giving vaccines before cancer develops, in order to prevent cancer development, particularly to people at high risk.
Several of the scientists funded by CPI are pursuing this approach. Unlike personalized vaccines, these vaccines are not individually designed for each patient. Instead, they target proteins and peptides shared by tumors across cancers and could be given to high-risk patients before the disease develops. Follow the links below to learn more about these projects.