Vaccines are the original immunotherapy, in the view of Ryan Sullivan, a cancer immunotherapy researcher and oncologist at Mass General Cancer Center. But many other modes of immunotherapy for cancer were approved first — checkpoint blockade drugs like Keytruda and engineered immune cell therapies like Yescarta. Shadowed by the successes of other therapies, the field of cancer vaccines was “seemingly dying,” Sullivan said.
Then, at the American Association for Cancer Research annual meeting in 2023, the late New York University immunologist Jeffrey Weber presented a Phase 2 clinical trial on a personalized cancer vaccine for melanoma developed by Moderna and Merck. That “lit the field on fire,” said Sullivan, who was involved with the research. The data showed the vaccine, when combined with Keytruda, greatly diminished the odds of a relapse, and was a turning point for the floundering field.
The result — along with later early phase clinical successes with cancer vaccines — opened the world’s eyes to the possibilities of cancer vaccines. Personalized vaccines, crafted from unique mutations from each individual patient’s cancer, seem to have few side effects on their own. This means they can probably be given on top of practically any other therapy program to enhance efficacy. Broader-based vaccines have already shown some promise in boosting CAR-T therapy for solid tumors. Cancer vaccines may also be able to help train the immune system to recognize and kill cancers related to viruses like HPV.
