Personalized mRNA vaccine cuts melanoma recurrence risk by 42% in late-stage trial
In a phase III study, the Moderna-Merck personalized mRNA vaccine intismeran reduced melanoma recurrence and death by 42% when added to Keytruda, compared with Keytruda alone.
A late-stage trial involving 1,137 patients with stage 3 melanoma showed that adding the personalized mRNA vaccine intismeran to Merck’s immunotherapy drug Keytruda lowered the two-year risk of cancer recurrence and death by 42% relative to Keytruda plus placebo. The vaccine, which is tailored to each patient using genomic sequencing of the excised tumor, was administered about nine weeks after surgery.
Patients receiving both treatments had an 82% recurrence-free rate after two years, versus 70% for those receiving Keytruda alone. Researchers said the vaccine trains the immune system to recognize tumor-specific neoantigens, complementing Keytruda’s T-cell activation.
"It will be seen as the first step toward using cancer vaccines to their full potential," said Dr. Robert Vonderheide, director of Penn Medicine’s Abramson Cancer Center.
"This treatment is about mopping up the cancer cells we can’t see," said Dr. Georgina Long, co-medical director of the Melanoma Institute Australia and trial lead.
"It essentially creates an army of killer T cells that are meant to recognize the tumor," said Dr. Shirin Bajaj, incoming director of head and neck melanoma at Mount Sinai.
Side effects were limited to mild injection-site pain and low-grade fever, similar to those observed with COVID-19 mRNA vaccines. The trial’s full data have not yet undergone peer review, and longer follow-up is needed to assess durability of benefit and overall survival impact.
The study’s findings will be presented at the European Society for Medical Oncology meeting in Madrid. Researchers plan to test intismeran in patients with advanced melanoma and are exploring the approach in other cancer types.