Clinical trial of a 7-peptide cocktail vaccine with oral chemotherapy for patients with metastatic colorectal cancer.

Abstract

The combination of a peptide vaccine and tegafur-uracil plus leucovorin (UFT/LV) were evaluated in patients with metastatic colorectal cancer refractory to standard chemotherapy.Thirty human leukocyte antigen (HLA)-A2402-positive patients were enrolled in the study. In a cycle of treatment, a vaccine comprising of seven synthetic peptides (five tumor antigen-derived and two vascular endothelial growth factor receptor-derived) was injected weekly, and oral chemotherapy, UFT/LV was given daily for four weeks followed by one week of rest. The immunological and clinical responses were evaluated at the end of every five weeks.Notable adverse events included grade 1 injection site redness/induration in 25 patients. Tumor imaging showed partial response in three patients, stable disease in 15, and progressive disease in 12. Survival analysis indicated that patients who exhibited positive cytotoxic T lymphocyte responses to all seven peptides had longer overall survival compared to other patients.A 7-peptide vaccine used with UFT/LV is safe and is recommended for further trials in patients with metastatic colorectal cancer.