A first-in-human study reported that a mutant KRAS peptide vaccine (mKRAS-VAX) was safe and induced KRAS-specific T-cell responses in 90% of high-risk participants. After a median 16.5 months of follow-up, none of the 20 patients developed pancreatic ductal adenocarcinoma, and some precursor lesions reportedly shrank or stopped progressing. The trial enrolled individuals with hereditary PDAC predisposition or concerning pancreatic abnormalities (NCT05013216). The paper in Cancer Discovery reported grade 1–2 adverse events, immunogenicity, and persistence of vaccine-induced clonotypes for up to two years using longitudinal TCR sequencing. The work is framed as proof of concept for vaccine-based interception—an approach designed to intervene before imaging detects cancer—while reinforcing that immune durability is a core clinical question for pancreatic cancer prevention strategies.