Application of E75 peptide vaccine in breast cancer patients: A systematic review and meta-analysis

The E75 peptide vaccine, derived from tumor-associated antigen HER2, is the most frequently studied anti-HER2 vaccination strategy for the treatment of breast cancer patients. It has been investigated in the several phases Ι/Π of the clinical trials and is currently being evaluated in a randomized multicenter phase III clinical trial. We conducted a systematic review and meta-analysis to clarify the outcomes of the E75 peptide vaccine including the therapeutic efficacy, the disease recurrence, the survival rate, and the side effects. Three peer-reviewed literature databases including the PubMed, Web of Science, and Scopus were sought. Of 29 trials assessed for eligibility, 16 were considered based on our inclusion criteria. Statistical analyses were performed by The Excel and STATA v.11.0. Meta-analysis of delayed-type hypersensitivity)DTH( reactions and CD8⁺-T cell levels, as immune responses, displayed the significant differences in the vaccinated groups compared to their non-vaccinated counterparts. In addition, the recurrence, and the overall and the disease-free survival were significantly different in the vaccinated subjects versus the control. Evaluation of the local and systemic toxicity of the E75 peptide vaccine demonstrated the minimal side effects. It seems that the E75 peptide vaccine is safe and effective, and can be used for further randomized clinical trials.