Moderna and Merck announced that their mRNA cancer vaccine, intismeran, succeeded in a Phase 3 melanoma trial, marking a significant milestone in personalized cancer treatment. The vaccine uses the same mRNA platform as Moderna's COVID-19 shot to deliver genetic code for cancer mutations to healthy cells, which then present these proteins as antigens to immune cells. The companies refer to the treatment as "neoantigen therapy" to avoid controversy surrounding mRNA and vaccine terminology, particularly amid criticism from Health Secretary Robert F. Kennedy Jr., who has reduced federal funding for mRNA research.

Georgina Long, who led the clinical trial, called the results "a landmark moment" with the potential to establish a new treatment paradigm. Dean Li, president of Merck Research Laboratories, emphasized the findings support personalized cancer care. Moderna CEO Stéphane Bancel described it as a pivotal moment for cancer research, noting that creating individualized mRNA treatments was once aspirational.

External experts, including University of Oxford's Lennard Lee, expressed optimism, calling it the first positive Phase 3 trial of an individualized neoantigen therapy. However, Lee cautioned that details on the magnitude of benefit, subgroup analyses, and long-term survival data are still needed to fully assess the treatment's impact and role in routine melanoma care.