A groundbreaking personalized mRNA vaccine for melanoma has shown promising results in a late-stage clinical trial, reducing the risk of cancer recurrence and death by 42% compared to standard treatment. The experimental vaccine, called intismeran, was developed by Moderna and Merck and is tailored to each patient using genomic data from their tumor. The trial included 1,137 Stage 3 melanoma patients who had undergone surgery and were treated with Merck’s immunotherapy drug Keytruda. Two years later, 82% of patients who received both the vaccine and Keytruda had no recurrence, compared to 70% in the placebo group.
Dr. Robert Vonderheide, director of Penn Medicine’s Abramson Cancer Center, called the results a “game changer,” noting that the vaccine could be a significant step toward realizing the full potential of cancer vaccines. The vaccine works by training the immune system to recognize and target abnormal proteins called neoantigens, similar to how standard vaccines work. Each patient’s vaccine was created in about nine weeks on average, demonstrating the feasibility of personalized treatment.
While the results are promising, some experts caution that the difference between the vaccine plus Keytruda and Keytruda alone is relatively modest. Dr. Shirin Bajaj, incoming director of Head and Neck Melanoma at Mount Sinai, noted that the treatment’s scalability may present challenges, as 17% of screened patients did not have sufficient tumor samples for vaccine creation. Despite this, the trial’s success has renewed optimism in the field of cancer vaccines, particularly for preventing recurrence rather than treating advanced disease.
The full data from the trial is yet to be published in a peer-reviewed journal, and patients will need to be monitored for several more years to assess long-term benefits. The vaccine is also being studied in advanced melanoma cases, with researchers hopeful that the concept could be applied to other cancers, including bladder, kidney, and lung cancer.