Survivin 2b peptide vaccine(Sapporo Medical University)

Immune checkpoint inhibitors (ICIs) have revolutionized the treatment of cancer by providing new options in addition to existing therapies. However, peptide vaccination therapies still represent an attractive approach, because of the antigen specificity. We identified survivin 2B peptide (SVN‐2B), a 9‐mer antigenic peptide encoded by survivin, and an SVN‐2B peptide vaccine‐based phase II randomized clinical trial targeting unresectable and refractory pancreatic carcinoma was undertaken. The SVN‐2B peptide vaccine did not have any statistically significant clinical benefits in that study. Therefore, we undertook an autopsy study to analyze the immune status of the pancreatic cancer lesions at the histological level. Autopsies were carried out in 13 patients who had died of pancreatic cancer, including 7 who had received SVN‐2B peptide vaccination and 6 who had not, as negative controls. The expression of immune‐related molecules was analyzed by immunohistochemical staining. Cytotoxic T lymphocytes were analyzed by tetramer staining and enzyme‐linked immunospot assay. Histological analysis revealed dense infiltration of CD8+ T cells in some lesions in patients who had received the SVN‐2B peptide vaccine. A high rate of programmed cell death ligand 1 expression in cancer cells was observed in these cases, indicating that CTLs were induced by SVN‐2B peptide vaccination and had infiltrated the lesions. The lack of a significant antitumor effect was most likely attributable to the expression of immune checkpoint molecules. These findings suggest that the combination of a tumor‐specific peptide vaccine and an ICI might be a promising approach to the treatment of pancreatic carcinoma in the future.

The prognosis of advanced pancreatic adenocarcinoma is still extremely poor. This study sought to determine the efficacy of, and immunological response to, peptide vaccination therapy in patients with this disease. In this multicenter randomized phase II study, patients with advanced pancreatic adenocarcinoma after gemcitabine and/or tegafur/gimeracil/oteracil were randomly assigned to 3 groups that each received a 2‐step treatment course. In Step 1, the groups received treatments of: (i) survivin 2B peptide (SVN‐2B) plus interferon‐β (IFNβ); (ii) SVN‐2B only; or (iii) placebo until the patients show progression. In Step 2, all patients who consented to participate received 4 treatments with SVN‐2B plus IFNβ. The primary endpoint was progression‐free survival (PFS) after initiation of Step 1 treatment. Secondary endpoints included immunological effects assessed by analysis of PBMCs after Step 1. Eighty‐three patients were randomly assigned to receive SVN‐2B plus IFNβ (n = 30), SVN‐2B (n = 34), or placebo (n = 19). No significant improvement in PFS was observed. Survivin 2B‐specific CTLs were found to be increased in the SVN‐2B plus IFNβ group by tetramer assay. Among patients who participated in Step 2, those who had received SVN‐2B plus IFNβ in Step 1 showed better overall survival compared with those who had received placebo in Step 1. Patients vaccinated with SVN‐2B plus IFNβ did not have improved PFS, but showed significant immunological reaction after vaccination. Subgroup analysis suggested that a longer SVN‐2B plus IFNβ vaccination protocol might confer survival benefit. (Clinical trial registration number: UMIN 000012146).