A Johns Hopkins University team reported early clinical evidence for a KRAS-mutant peptide vaccine aimed at preventing progression in people at high risk for pancreatic ductal adenocarcinoma (PDAC). In a Phase 1 trial described in *Cancer Discovery*, researchers tested a peptide-based vaccine incorporating six common mutant KRAS (mKRAS) variations in 20 participants with genetic predisposition and confirmed pancreatic lesions. The study reported protective, antigen-specific T-cell responses and a slower progression from lesions toward cancer. Participants experienced only mild, self-resolving side effects such as fatigue and flu-like symptoms. The investigators said the immunology signals support continued development in larger trials. While the results are early and limited to a small cohort, the approach targets a defined at-risk population rather than treating PDAC after diagnosis.