Phase II trial of HER-Vaxx, a B cell peptide-based vaccine, in HER2-overexpressing advanced gastric cancer patients under platinum-based chemotherapy (HERIZON).

HER-Vaxx plus standard chemotherapy exhibits an excellent safety profile and improves OS. Furthermore, vaccine-induced immune response was significantly associated with reduced tumor size compared to standard-of-care chemotherapy. The presented vaccination approach may substitute for treatment with trastuzumab, upon unavailability or toxicity, based on further evidence of equivalent treatment efficacy.