What Doctors Want You to Know About the New “Personalized” Cancer Vaccine Making Headlines

4 min readNew clinical trial results suggest a new vaccine could dramatically improve survival rates for people with melanoma. Intismeran is still in development. Doctors say it can likely be used for other forms of cancer in the future. Cancer is the second leading cause of death in the U.S. and a major source of fear and anxiety for plenty of Americans. With that, it’s fair to want to do what you can to lower the risk of developing cancer, now and in the future. While there already is an anti-cancer vaccine (Gardasil 9, which protects against HPV that can later turn into cervical cancer) there’s not yet a shot that targets a range of cancers.But now, there’s a “personalized” cancer vaccine that’s getting plenty of buzz. It’s called intismeran and, while it’s still in development, it’s racking up some impressive numbers in clinical trials when it comes to preventing melanoma, a deadly form of skin cancer, from recurring. What’s getting even more attention is that intismeran is a customizable mRNA vaccine that’s tailored to each individual—and there’s already some thought that this could be used to target other forms of cancer in the future.To be fair, we’re not there right now. But things are looking really good for intismeran and the future of cancer care. Here’s what we know so far.Meet the experts: Philip Felgner, PhD, a DNA and mRNA-based vaccine development expert and founder of the Felgner Lab at the University of California, Irvine; Emily Nadelmann, MD, a clinical assistant professor of dermatology at George Washington School of Medicine and Health Sciences; and Gary Goldenberg, MD, an assistant clinical professor of dermatology at Icahn School of Medicine at Mount Sinai.What did the latest clinical trial results find?The information we have on clinical trial results comes courtesy of pharmaceutical companies Moderna and Merck and hasn’t been officially published yet. However, the two companies recently issued a joint press release, sharing information on their phase 3 results for intismeran. According to the release, the mRNA vaccine “met endpoints of recurrence-free survival,” although the companies didn’t share specific numbers.That said, results from a phase 2b trial of intismeran were shared earlier this year at the American Society of Clinical Oncology’s annual meeting. According to the researchers, a combo of intismeran and the immunotherapy medication Keytruda lowered the risk of melanoma recurrence (i.e., the cancer coming back) by 49 percent after five years. It also reduced the risk of the cancer spreading and patients dying from melanoma within five years by 59 percent.Why are people so excited about this vaccine?There are a few reasons why this vaccine is getting so much attention, even while it’s still in clinical trials. “Melanoma is one of the deadliest types of skin cancer. If not detected early, it can spread throughout the body,” says Gary Goldenberg, MD, an assistant clinical professor of dermatology at Icahn School of Medicine at Mount Sinai. But while immunotherapy has helped with outcomes for patients with melanoma, the vaccine seems to help even more when the two are used together. “This is very exciting,” Dr. Goldenberg says.Philip Felgner, PhD, a DNA and mRNA-based vaccine development expert and founder of the Felgner Lab at the University of California, Irvine, agrees. “This is the first large phase 3 study to demonstrate meaningful clinical benefit from an individualized mRNA cancer vaccine,” he says.The customizable part is important, too. “It's built for one patient at a time,” says Emily Nadelmann, MD, clinical assistant professor of dermatology at George Washington School of Medicine and Health Science. “It relies on the same mRNA technology behind the COVID-19 vaccines, now directed against cancer.”Could this be used against non-melanoma cancers?This is “very likely,” according to Dr. Nadelmann. “This is central to the enthusiasm,” she says. “Because the vaccine is reprogrammed with whatever mutations a given tumor carries, the same platform can in principle be directed at nearly any cancer,” she says.In fact, clinical trials are already happening with pancreatic, lung, and triple-negative breast cancers, Dr. Nadelmann points out. “Most notably, a personalized mRNA vaccine in pancreatic cancer, long among the most difficult to treat, produced durable immune responses and delayed recurrence in the patients who responded,” she says. “The approach appears broadly applicable, though each cancer presents its own obstacles.”Why start with melanoma?The researchers didn’t just pick melanoma to work with randomly. Melanoma has “long been the testing ground for immune-based therapy,” according to Dr. Nadelmann. “Years of sun exposure leave it densely mutated, giving the immune system an unusually rich set of targets and making it one of the most immune-visible cancers known,” she says. Some other forms of cancer are “more subtle” and have fewer mutations, Dr. Felgner says.What happens now?It’s not entirely clear. Merck and Moderna said in their joint press release that they will present the latest data soon and then “shared with regulatory authorities.” From there, it would need approval from the Food and Drug Administration (FDA) before it can be made available to the public.Carina Hsieh, MPH, is the deputy features editor of Women’s Health. She has more than a decade’s worth of experience working in media and has covered everything from beauty, fashion, travel, lifestyle, pets, to health. She began her career as an intern in the fashion closet at Cosmopolitan where she worked her way up to Senior Sex & Relationships Editor. While covering women’s health there, she discovered her passion for health service journalism and took a break to get her Masters in Public Health. Post-grad school, she worked as a freelance writer and as The Daily Beast’s first Beauty, Health, and Wellness Reporter. Carina is an alum of the Fashion Institute of Technology and the Yale School of Public Health. She and her French Bulldog, Bao Bao, split their time between Brooklyn and Connecticut. She enjoys reformer Pilates, (slow) running, and smelling the fancy toiletries in boutique fitness class locker rooms.