The Next Chapter of mRNA

Even while being diverted to produce billions of doses of the COVID vaccine, the cancer-vaccine program continued to enroll patients. This October, almost a decade after starting development on an mRNA cancer vaccine, Moderna and Merck reported the “whopping effect” that Zaks had hoped for. Intismeran, combined with pembrolizumab, reduced the recurrence of cancer by 42% in people with mid- to late-stage melanoma. And the benefit, as Zaks had predicted, started to emerge after six months of treatment. “The immune system takes time to be activated,” says Dr. David Berman, chief development officer at Moderna.

Beth Ryzyk heard the promising results while watching the news. In 2024, after being diagnosed with Stage IIIC melanoma, Ryzyk had decided to join the study of intismeran at Memorial Sloan Kettering Cancer Center (MSK). Surgeons removed her tumor as well as the lymph nodes under her arms, and after genetic sequencing, she learned she had 80 tumor markers. In the study, Moderna and Merck focused on the markers they thought would trigger the strongest immune response and designed a personalized vaccine for each of the patients in the treatment group. “It’s pretty amazing that they can individualize it to me and teach my body what to fight,” she says. The treatment is straight-forward enough that she received the intismeran and Keytruda near her home at MSK’s location in Westchester, New York. She still doesn’t know if she received the vaccine or a placebo, since the study has not been published yet, but she gets scans four times a year. Two years later, “so far so good—nothing has popped up, and it’s the best I can ask for,” she says. “The hard thing about melanoma is that it can come back to any part of your body, and it’s always in the back of your mind. So if it prevents 42% [of recurrence], I’ll take that.”