Personalized peptide and DNA vaccines in pancreatic cancer: no grade 3 or higher adverse events and a non-significant survival trend in two phase 1 trials

Two phase 1 trials (NCT03956056 and NCT03122106) gave patients with resected pancreatic ductal adenocarcinoma personalized cancer vaccines — synthetic long peptide or DNA — after surgery and adjuvant chemotherapy, with neoantigens selected from tumour and normal exome and RNA sequencing. The vaccines caused no adverse events of grade 3 or higher and elicited polyclonal neoantigen-specific T cell responses, confirmed by transducing the expanded T cell receptor clonotypes into the patients' own blood cells. Against a propensity-matched institutional cohort, median overall survival was 4.4 versus 3.5 years — a trend that did not reach statistical significance (log-rank P = 0.23). These are early-phase, non-randomised safety and immunogenicity studies in a cancer that has resisted immunotherapy; the survival comparison is exploratory and cannot establish benefit.