Neoantigens are ideal targets for dendritic cell (DC)
vaccines. So far, only a few neoantigen-based DC
vaccines have been investigated in clinical trials. Here, we reported a case of a patient with metastatic
gastric cancer who received personalized neoantigen-loaded monocyte-derived dendritic cell (Neo-MoDC)
vaccines followed by combination
therapy of the Neo-MoDC and
immune checkpoint inhibitor (ICI). The patient developed T cell responses against neoantigens after receiving the Neo-MoDC
vaccine alone. The following combination
therapy triggered a stronger immune response and mediated complete regression of all
tumors for over 25 months till October, 2021. Peripheral blood mononuclear cells recognized seven of the eight
vaccine neoantigens. And the frequency of neoantigen-specific T cell clones increased obviously after vaccination. Overall, this report describing a complete
tumor regression in a
gastric cancer patient mediated by Neo-MoDC
vaccine in combination with ICI, and suggesting a promising treatment for patients with metastatic
gastric cancer.