A personalized mRNA vaccine tested at UC San Francisco has become the first to successfully prevent the return and spread of cancer in late-stage clinical trials. The results could signal a new era of vaccines to treat a range of cancers, says UCSF Professor of Medicine Adil Daud, MD, who led the university’s trial site.
Bay Area tennis pro Mark Orwig, 73, was diagnosed with melanoma in 2023. After physicians removed a tumor from his cheek, Orwig feared the cancer would return. His physician thought a clinical trial at UCSF might offer hope and referred him to Daud.
Daud is a UCSF Health melanoma specialist and directs the UCSF Melanoma Program, where he researches how tumors outsmart the immune system in hopes of developing better, more personalized medicines for the hardest-to-treat cancers.
Daud, Orwig remembers, offered him three different trials to choose from. But one, Daud told him, was groundbreaking enough that it just might revolutionize the way medicine treats cancer.
Orwig became one of about 1,140 patients to participate in a late-stage clinical trial that found that adding a personalized mRNA vaccine to existing melanoma treatment reduced patients’ risks of the skin cancer returning or spreading. The trial's results, led by pharmaceutical companies Merck and Moderna, are not yet publicly available. Still, the firms’ previously reported findings from an earlier phase trial showed that the combination treatment reduced the chance of recurrence by nearly half compared with patients who received standard treatment alone. The dual treatment also reduced the risk of the cancer spreading by nearly 60%.
“Cancer vaccines have been in testing for decades, and this is the first cancer vaccine that’s shown proof of efficacy in a randomized controlled clinical trial,” Daud says. “It’s amazing news — if this works for melanoma, it could work for other cancers too.”