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

AIM 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. PATIENTS AND METHODS 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. RESULTS 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. CONCLUSION A 7-peptide vaccine used with UFT/LV is safe and is recommended for further trials in patients with metastatic colorectal cancer.