A phase I study of a 5-peptide vaccine with immune modulators for patients with refractory metastatic colorectal cancer

Interventions: 1)Immune modulators, composed of cyclophosphamide, metformin, celecoxib and cimetidine are administered orally for 1 week 2)Induction phase: 5-peptide cocktail vaccine weekly in combination with immune modulators are administered for 8 weeks 3)Maintenance phase: 5-peptide cocktail vaccine biweekly in combination with immune modulators are administered for 8 weeks 4)Extension phase: maintenance therapy is allowed depending on patient condition Primary outcome(s): The safety of the immune modulators with/without 5-peptide cocktail vaccine Study Design: Single arm Non-randomized