Late-stage clinical trials have demonstrated that a tailored mRNA vaccine evaluated at UCSF is the first to successfully block the recurrence and dissemination of cancer.
Modern oncology is standing on the edge of a fundamental shift. For decades, traditional cancer treatments like chemotherapy and radiation have attacked tumors directly while taking a heavy toll on healthy tissue along the way. Therapeutic cancer vaccines operate on an entirely different principle. Instead of scorched-earth tactics, these injections teach the body’s immune system to recognize and destroy cancer cells on its own, building a lasting defense capable of preventing relapse years down the line.
That long-held vision is finally turning into clinical reality. In August, pharmaceutical companies Merck and Moderna announced that their personalized cancer vaccine succeeded in Phase 3 trials, marking the final phase before moving to the FDA for approval and landing on the market.
Clinical Trial Results and Patient Impact at UCSF
The implications of this breakthrough are already visible in clinical settings. At UC San Francisco, Professor of Medicine Adil Daud led the university’s trial site for the experimental treatment. UCSF Health melanoma specialist Adil Daud directs the UCSF Melanoma Program, bringing experimental hope to patients facing aggressive skin cancers.
Among them was Mark Orwig, a 73-year-old Bay Area tennis pro diagnosed with melanoma in 2023. After surgeons removed a tumor from his cheek, Orwig turned to Daud for a clinical trial that might keep the disease from coming back. He joined about 1,140 patients enrolled in the late-stage evaluation.
Cancer vaccines have been tested for decades, yet this marks the initial instance of one demonstrating verifiable efficacy within a randomized controlled clinical trial. It’s amazing news — if this works for melanoma, it could work for other cancers too.
While complete trial data remains under wraps, earlier-phase findings released by the manufacturers showed that pairing the personalized vaccine with standard care reduced the chance of recurrence by nearly half compared with standard treatment alone. The dual therapy also cut the risk of the cancer spreading by nearly 60 percent.
Personalized mRNA Technology Versus Off-the-Shelf Treatments
The rapid evolution of mRNA technology during the COVID-19 pandemic provided the exact manufacturing bridge researchers needed to customize vaccines for individual tumors. Older cancer vaccines largely failed because they relied on a one-size-fits-all, off-the-shelf approach.
As Adil Daud explains, standard vaccines generated immune responses, but those responses missed the exact mutations driving a specific patient’s tumor. Because tumors accumulate distinct mutations as they evolve, no two tumors are exactly alike.
Personalized vaccines solve this by sequencing a patient’s cancer DNA to build a custom injection that targets those specific cellular errors. That high level of individual tailoring comes with a steep financial hurdle, as each vaccine costs over $100,000 to manufacture.
Not every malignancy requires a bespoke formulation, however. Certain rare cancers produce uniform genetic abnormalities across different patients, allowing for off-the-shelf vaccines. Molly Hones, a 31-year-old liver cancer patient treated at Johns Hopkins, received an off-the-shelf experimental vaccine in April 2024 for fibrolamellar carcinoma. Within five months, her stage 4 cancer reached full remission.
Broadening Cancer Applications and Future Treatment Access
The success in melanoma has opened the floodgates for broader clinical testing. Researchers are currently evaluating personalized mRNA vaccines in clinical trials targeting cancers of the lung, bladder, kidney, pancreas, and stomach.
Kristen Dahlgren, a breast cancer survivor and chief external affairs officer at the Parker Institute for Cancer Immunotherapy, highlighted the magnitude of this paradigm shift.
Dr. Cathy Wu, a cancer vaccine researcher at the Dana-Farber Cancer Institute, noted that current therapeutic applications focus heavily on guarding against recurrence. We’re using the vaccines to prevent relapse in those patients at high risk of relapse,
Wu stated.
With Moderna’s melanoma vaccine moving toward FDA review, the treatment could become available as early as next year. Meanwhile, patients like Mark Orwig remain in remission, looking forward to the future.
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