Australia has opened the Paedneo‑Vax trial, the first multisite pediatric study testing individualized mRNA vaccines tailored to each child’s tumor. Funded by Providence Therapeutics, the Australian government and philanthropists, the study enrolls children with aggressive brain tumors to evaluate safety, immunogenicity and early signals of efficacy. The trial applies personalized neoantigen mRNA technology in a pediatric oncology setting, where immunotherapy options are limited and tumor antigen landscapes differ from adults. Results could accelerate development of individualized cancer vaccines for hard‑to‑treat pediatric indications and inform global pediatric cancer vaccine strategies.